This new horn design was introduced in 1934. It is attached direct to the 207 six cylinder engine and was so successful there was almost no changes through 1953.
As shown in these photos this 1934-36 horn was attached to a flat foot that secured it to the center of the intake manifold. A long nose directs the sound to the area very close to the radiator cooling fan.
A slight change to the exterior appearance occurred with the new 1937 216 cubic inch engine. Possibly to keep it away from the high temperatures of the exhaust manifold, the horn was relocated. It now was attached to the forward leg of the intake away from engine heat.
The “bell” part of the horn was shortened to keep it the same distance from the fan. There, it remained on cars and trucks until the 216 engine was discontinued in late 1953.
It was so well designed it rarely required attention. A single screw secures the rear half circle cover. When removed the inner workings are exposed for an occasional tone adjustment.
The revised Chevrolet 235 and 261 high pressure inline six cylinder engine (1955 through 1962) was given a much better cooling system than prior years. This was due to a big change in the water pump and how it attached the front of the engine block.
The prior 216 and early 235 design pulled coolant out of the engine block through two quarter size holes, into an exterior pump, then forced it through the lower radiator hose and back into the engine block. This system worked well for millions of Chevrolet cars and trucks for at least 16 years.
One of the difficulties began to develop as these vehicles became older and were exposed to faster speeds of more modern roads and radiator coolant water contained a high calcium content.
Calcium started to slowly accumulate inside the block but even more in the radiator cooling tubes. The coolant temperature would rise in the block due to slower water circulation.
This was first noticed in the low geared 1 ½ and 2 tons, even with their extra row of radiator cooling tubes. Local radiator shops would remove the top radiator tank and “rod out” the cooling tubes to restore most of the original radiators ability.
With the introduction of 2 new Chevy six cylinder in 1955, General Motors made a change in the water pump that would at least postpone this over-heating problem for many more years than the earlier engines.
Now, the water pump propeller actually was inside a 4” hole in the front of the block. It could move a higher volume of coolant through the block. Chevrolet cars and trucks could now be used so many more miles before this rodding of the tubes was necessary.
With General Motors wisdom, they designed their new high pressure 235 and 261 engine to easily fit in the place of a failing earlier 216 engine. The main problem with this engine exchange was the longer length of the new water pump shaft.
Local mechanics would then either cut some metal from the upper and lower air dam to move this radiator forward a few inches or shorten the pump shaft to provide radiator clearance for the fan on a new 7” pulley.
The word spread quickly that the shaft could be cut and the 4” diameter pulley from a 1953-1954 would press in the proper position. (Most shops could find one of these pulleys on a nearby used engine)
All fit well but the rotating RPM speed of this small 4” pulley turned the fan and pump 20% faster at the same vehicle speed. Because of the low engine gearing of the larger 1 ½ – 2 ton trucks we have heard owners feel their water pump experienced “cavitation” (the fan is turning so fast water flow will almost come to a stop). It may not boil the coolant but it just might! At slower road speeds the water temperature returns close to normal. A small 18” fan from an early 216 donor engine was also required to prevent contacting the lower radiator tank.
NOW enters another modified water pump that has a much flatter 7” diameter pulley. This lowers the fan speed to the correct RPM that GM intended to be used on ½ ton up to the 2 tons. It was a one size fits all!
It is the other short shaft pump design! You can easily install this modified 235 and 261 engine in the 1953 and older truck (and cars). It is strongly recommended that you use this pulley pump for Chevy trucks rated over ½ tons!
It requires the correct wider four blade 235 fan, however the blades must be bent slightly forward to miss the lower radiator tank.
Therefore, if you want to operate your 235 and 261 engines water pump at a slower speed as GM intended, the 7 inch pulley design is the way to proceed. It will cool ¾ to 2 tons with lower differential gearing at high speeds with no boiling, just as the vehicles were designed. Yes, Jim Carter Truck Parts has the new updated pump assemblies available at a price of $159.00 (a used original wide blade fan is by another order).
A small 4 inch diameter pulley water pump have been placed on a 235 or 261 engine since they were first introduced. They usually work well with vehicles with clean radiators on cars and ½ ton light vehicles that have been given a higher speed differential. Not recommended for larger trucks as water temperature will raise at higher speeds! We have these that operate well (without add-on air conditioning) at our company at $130.00.
As the owner of Jim Carters Truck Parts, I can assure you we have sold over 500 short shaft water pumps with 4 inch pulleys in the last 10 years. Return rate is about 4%. I suspect it is rarely due to an inefficient pump but rather the new customer not aware of the difference between a 216 and later 235 six cylinder. Maybe a few were using them on a low differential ratio ¾ to 2 ton truck.
Does the 4 inch pulley cool as well as the 7 inch design? Probably not on larger trucks! In some situations, if your radiator has calcium build-up, the coolant flow can be so restricted, your temperature gauge will show an increase at highway speeds. The 4 inch pulley turns the water pump much faster than GM intended!
With the low differential gearing (as in the ¾ ton to a 2 ton) plus driving higher speeds, the increase engine RPM will definitely cause temperature increase. It can go so far at very high speeds causing the water to cavitate and the coolant circulation will almost come to a stop! It may not boil the coolant but it just might!
4 inch pulley
7 inch pulley
COMING MARCH 2014!
The set of 12 mirror polished stainless trims used on the 1947-54 deluxe Chevrolet panel truck. Includes the needed attaching clips. Show quality Part Number TRT400 – set $1,550.00.
AVAILABLE APRIL 2014
The long mirror polished stainless trim that secures to the upper front fender of the 1947-54 Chevrolet deluxe panel truck. Securing clips are built into strip. Show quality Part Number TRT402 – Pair $195.00.
NOW IN STOCK!
Rear door light switch. For rear left double door and door post on 1937-54 panel truck. Factory indentions are in the body and door. Many new parts make this switch fit just right.
Part Number EL409 – Pair $69.50.
The Korean War has ended and copper used in quality chrome plating is now readily available at an acceptable price to commercial buyers. General Motors loses no time introducing a deluxe pickup in both their Chevrolet and GMC lines. Quality chrome plating was required for this project and was now in stock. Other metals have also dropped in price including stainless steel.
The new deluxe GMC pickup was far above the appearance of earlier years even though the mechanics were virtually unchanged. With more disposable income in the US, General Motors gambled that many buyers would purchase a new upscale truck even if they did not have immediate hauling needs.
Actually GM invested very little to make their top of the line pickup stand out above the crowd. Using their base model, the following made up much of this special pickup:
- Grille, bumper, grille surround and hub caps are chrome plated.
- The exterior side window and new one piece “panoramic” windshield is surrounded with high polished stainless steel.
- Wing vents assemblies are combination chrome and polished stainless.
- The end of the rolls in the bed sides have plastic reflectors (actually from a 1953 Buick) and held in place with a GMC only stainless ring. A small screw hole was in only the deluxe pickup bed side to secure this assembly. Not on Chevrolet.
- Chrome tail light ring.
- The interior upholstery consisted of cloth covered cushions rather than traditional vinyl material on trucks of all prior years.
- The pleated door panels matched the material in the seats.
- The unusual metal interior was painted the reverse of the deluxe Chevrolet colors. Thus, dark being the primary color. A lighter shade was the dash, steering column and steering wheel.
- Driver’s side are rest.
- Yes, like the deluxe Chevrolet, the running boards were the lower body color.M
- A different contrasting color, not necessarily the body, is placed on the wheels.
A few items in the attached GMC advertisement, placed in a major magazine. Were extra cost factory options:
- Hydra-Matic transmission.
- White top, to reflect sun.
- Jet plane hood ornament.
- Factory Clock.
Note: A rear bumper was always an option in 1954. Their problem: They prevented a pickup from backing close to a loading dock. When carrying merchandise or walking livestock into the pickup the gap caused dangerous falling problems for some owners. The beginning attached factory photo of this article shows the tailgate totally open and thus down vertically to eliminate the gap. This can only happen with no rear bumper.
To add better night visibility to all trucks, Suburbans and panel trucks, General Motors offered a 4 inch diameter reflector as a dealer installed accessory. With the single small factory taillight, seeing of these vehicles on the road could be difficult especially if their one bulb burned out. To help correct this problem GM offered a larger reflector that could be attached to the rear license plate bracket. It greatly improved visibility to others at the rear during night driving.
This was a time when town street lights were limited. Of course, on the open road these were no lighting along the highways! This simple GM reflector was offered by the dealers to prevent rear end accidents. The customer could buy this dealer accessory from about 1940 through 1953. One of the attached photos is taken from a 1949 Chevrolet Truck Data Book. The 4 inch lens is a Stimsonite # 24 and the metal Guide ring has a stamping of X-19.
Jim Winters of Rochester, Minnesota has both a restored 1946 panel truck and ½ ton pickup. He found these reflectors for both his vehicles at local swap meets. Few people recognize what these reflectors were used for. Jim found his in a box of miscellaneous unmarked parts.
We recently had a local radiator repair shop clean the rust from an older used gas tank. They submerged it in a cleaning acid tank overnight. The price was $65.00. WOW! Several months later we discovered an “old school” method that would have cost about $1.00. Oh well, we live and learn.
Back in the days of the Great Depression money was a scarce commodity and economical methods in life were used or otherwise things probably did not get done. It was discovered that agricultural molasses (not what you buy in the grocery store) mixed with four parts water removed rust. Fill your tank with this combination and wait about a week. Surprise! Your gas tank is shiny clean inside.
You can even put a lid on a five gallon bucket from a hardware store and small parts covered with this formula will have all the rust removed in less than a week.
Agricultural molasses is used to mix with livestock feed. It causes farm animals to eat otherwise less desirable feeds because of its attractive sweet taste.
Retail price at a livestock feed store is about $2.00 for 10 pounds.
This data is provided by MIKE RUSSELL of COLUMBIA, MISSOURI.
Another cleaning Technique!
Several years ago, we heard of a gas tank cleaning method that cleans most tanks every time and its FREE!
Attach the gas tank to a farm tractor large rear wheel before a day in the field. Add about a pint of ¼” gravel. The slow rotation of the large wheel will move the gravel continually inside the old tank. Sometimes by noon, the rust is all removed as the gravel continually moves inside the tanks.
The first year of the Chevrolet pickup with a Hydramatic transmission was 1954. Though it did not find a large percentage of buyers, this truck did open the door for an increasing number of this transmission in the coming years.
When sitting in the 1954 Chevrolet truck cab with this new option, some changes are immediately noted. To operate the starter motor on the original six cylinder, a button is pushed with the driver’s thumb just above the headlight switch. The ignition switch still has 2 positions as earlier years.
The truck with a Hydramatic has an automatic choke on the carburetor, there is no need for manual pull choke. Thus, GM installed a small blank out plug in the hole where the choke lever is usually found (at the left of the radio position). At the right is another plugged hole which is usually for a throttle lever.
Of course, the main focal point is the Hydramatic shift selector attached on the column below the steering wheel.
For the new owner not acquainted with a Hydramatic, a paper sheet is slid over the sunvisor pad. It lists the instructions for successfully operating those types of transmissions.
An interesting feature on the Hydramatic: Turn off the engine while stopped in reverse and the transmission is in park!
A problem when installed was that it lessened the visibility of the front license plate. Therefore, another change was made during the installation. The license was moved to the center of the front splash apron from the factory position on the right side. In the kit were two small rubber plugs. These filled the factory license bracket holes that existed when the factory license bracket was removed.
One of the rarest Chevrolet dealer installed truck accessories of the 1950′s. Charles Callis of Union City, Tennessee recently found this original radiator cover that he installs for shows on his 1953 1/2 ton.
Note the Chevrolet logo on the lower right side to prove it’s the real thing!
It is pictured in the 1949 Chevrolet Salesman’s Data Book on the Truck Accessory page. Chevrolet describes it as:
“For all models of trucks. Adjustable; constructed of Fabrikold. Aids engine warm-up.
Protects engine from cold blasts. Improves efficiency in stop-and-go operations.”
The thin oil cloth type material did not last long either on the truck or during off season in storage. No doubt the dealer discarded his unsold stock in a few years.
You can contact Charles by email at: email@example.com
What an unusual idea! If you have clear coated your bedwood, replace the metal bed strips with dark stained wood.
Of course, this is for a pickup not used for hauling, however as the owner said “If you clear coated your bedwood instead of painting it as original, you were not planning to work with it anyway”.
The full rear quarter panels for the 1947-55 Chevy/GMC Suburban were made all the same at the metal stamping manufacturer. To save money these panels were not made different if the Suburban was to have the double doors or the tailgate style opening in the rear.
Thus, when the Suburban was provided with a lift and tailgate combination the 4 holes for the “double barn door” hinges in the quarter panels were filled with rectangular rubber plugs. This was not just for appearance but prevent rain water from reaching the body interior.
These photos show the plugs painted in body color; however it is questioned if this is correct. By 1950, Suburban buyers had the choice of the 12 pickup colors. It would have been more economical for all to have black rubber plugs instead of 12 boxes with the optional color prepainted plugs on the assembly line.
The other thought: These plugs were painted when the full body was given its final color. This would mean GM planned on the enamel body paint being of the quality that would successfully adhere to rubber over the years. We don’t usually see this combination in other GM vehicles. Special paint for rubber only is used!
Comments on how it really occurred: Email us at firstname.lastname@example.org
On an early Monday morning a customer, Mike Riley of Kansas City stopped by our shop to obtain some older Chevy truck parts needed during the past weekend. As I followed him to his mid-1980’s Chevrolet pickup he brought my attention to his new white paint job. He read about a home garage procedure on the internet and decided to try it.
He certainly was proud of how nice the paint looked. The project began with the usual fine sanding, taping trim, and covering windows. Next came the surprise that has generated this article. Mike bought 2 ½ quarts of industrial grade Rustoleum paint from a local hardware store. He also purchase 2 ½ quarts of Acetone to be used as the thinner.
Spraying the 1 to 1 mixture with his small home compressor was adequate. If the small compressor needed to occasionally build up pressure, no problem. It takes 20 minutes for the paint to dry to the touch, so it easily blends together. One coat does it all!
I was amazed at how nice it looked in our driveway that morning. Mike said the rules were to not polish the drying paint for 60 days. He had just polished the two month old paint on the nose of the hood that morning and I must admit it had a great smooth shine.
This procedure is probably not for the show truck but for the fun daily driver it may be just the way to go for the “do- it yourself” restorer. Mike says the industrial Rustoleum colors are limited so you must pick a more common choice when deciding.
Another important tip while using this painting method; Mike didn’t want to get paint overspray throughout his garage so he did the procedure outside in his driveway. A garden hose used by a friend kept the concrete wet during the spraying. This helped eliminate dust in the painted surface but equally important stopped overspray from settling on his driveway.
Before 1954 on 1/2 tons, the frame rails were given a large arch as they passed over the rear axle housing. With a broken leaf spring or overloading the bed with too much weight, the frame rails will lower many inches before contacting an axle bumper. It was a system that worked for over 20 years on 1/2 tons when the frame rails were forced down toward the rear axle. A hard rubber axle bumper was placed under the hump in the frame to prevent metal to metal contact when this occurred.
For 1954 a totally redesigned pickup bed resulted in a three inch increased depth of the bed for more load volume. Some of this increase required a lower arch in the frame rail over the axle. There would be less space here so the rubber axle bumper was changed in length and was moved to the side of the frame. See photo!
Therefore, this prevents a correct interchange between the 1949-53 1/2 ton frame and the 1954 and newer frame. If this is done the beds will not have the correct relationship to the height of the cab.
1947 to 1953
1947 to 1953
1954 to 1955
1954 to 1955
Warning: When installing an updated duel chambered master cylinder under the floor of an older GM truck, a brake line modification may be necessary.
It is not acceptable to allow the modified brake line to touch or be very close to the exhaust pipe. During long trips, the exhaust heat can cause a rise in the brake fluid temperature to near boiling level. Modern master cylinders do not have a vented cap to release line pressure so fluid will be forced out through wheel cylinders. The early single chambered caps are vented to prevent this.
Check your brake lines on non-original trucks. Do not allow a safer system to leave you without brakes.
Needed are some logs without bark and a table saw. Cut in half and add tongue and groove. You have a truck flat bed!
Though they have been recovered with cloth instead of factory “leatherette”, they are correct in all other ways. What is interesting is how GM made the optional right side seat to fold up against the dash. This was necessary to allow easier access to merchandise up front. No need to unload freight to get to the front storage area.
It appears the seat frame and floor is painted the original grey color. A thin sheet of insulation is placed between each of the body supports. This was to lessen road noise and slow some heat from entering the cab on hot days.
Another interesting feature on panel trucks; the single horizontal oak board on each side of the interior helps prevent damage to the exterior sheet metal walls. If a stack of transported items tipped while the panel truck was making a corner, there was less chance of dents being placed on the sides.
Note the long metal lid over the tool box which is under the factory optional right seat. This is only provided in the panel truck and canopy express bodies.
What an ingenious way to keep a tail light in view! General Motors realized that with the tail gate in the lowered position the center tail light still had to be seen by the following traffic. At times the gate will stay lowered when longer freight is carried.
Therefore, the 5” round light is attached to a swing bracket. This bracket is moved by a ¼” vertical rod inside the tailgate. As the gate is lowered, the rod is moved by a hidden attachment on the edge of the body. Thus, the light is always visible!
These photos are of a 1953 Canopy Express owned by John Dunkirk of Southaven, New York.
Leaving your truck, car, or most all gasoline operated equipment in storage is asking for trouble! Many of us, as hobbyists, collect more cars and trucks than we will drive a least monthly. They sit in the back of your garage or are stored across town in a friend’s garage, barn, etc.
Three to five years later when it is time to move them, they usually won’t start. You find in some cases, you cannot even get fuel to the carburetor.
After placing the blame on the carb, fuel pump, or filter, you finally (after hours of work) it comes down to bad gasoline. How did this happen?
The answer is simple. In today’s world ethanol is added to some gasoline as much as 10%. It gives more fire power to the gasoline that has been reduced in octane partially with additives that help lower air pollution.
This ethanol (alcohol) is damaging to many rubber and neoprene seals in your fuel system. Even worse, with the formula of modern gasoline plus ethanol, it will even change to sludge in your fuel system including the tank during long storage. Additives placed in ethanol gas to prevent fuel deterioration is said to be effective not more than about 1 ½ years.
All this spells “Big Money” to clean your fuel system. Just taking your fuel tank out of your vehicle, having it cleaned at a radiator repair shop (there aren’t many of these businesses anymore) will cost a minimum of $300.00.
We recently visited a small engine repair shop where 30 hedge trimmers, chain saws, and weed whackers were waiting to be repaired. The shop owner said 95% were there because of using gasoline with ethanol.
The answer to prevent this problem may be easier than you think. If possible STOP using gasoline with ethanol in your vehicles that are rarely driven or started. In our state, Missouri, there is no ethanol in the premium grade gasoline http://e0pc.com/MO.php. This maybe the answer in your area. Check with your state and see if your premium gas is ethanol free.
Some of you may remember the days prior to the 1970’s when you bought a vehicle that had been sitting 5 to 10 years. The gasoline smelled terrible but the motor would start. If it had brakes, you could even drive around the block. There was no alcohol in the gasoline.
Use premium gasoline in your stored vehicles or any yard equipment with limited use if it is without ethanol.
In Missouri, the approximately .20¢ extra per gallon for premium fuel far outweighs the headaches later!!
We ask our readers: What is the correct color for the letters and numbers for the 1947-53 Chevrolet truck dash gauges? Were they white? Have they slightly yellowed after 50 years and now have a more cream color?
Our company has made the decals both with white and slight yellow hue. We had assumed the originals have slightly yellowed with age. See photo.
I welcome your opinions at email@example.com
Surprise! The well known GMC grilles from 1949 through early 1955 use the same bars. This includes the more popular ½ ton through the very large over the road and quarry trucks. Chrome or painted, the four horizontal stamped metal bars are identical. Look at the following photos. The grille bars interchange!
In the days when car and truck owners as well as mechanics did maintenance, GM made these responsibilities much less complicated. An excellent example was the screen below the engine oil pump.
Due to no oil filters and no detergent additive in the motor oil (to keep dirt in suspension), the oil pump screen was necessary. Tiny dirt particles settled to the bottom of the oil pan as was expected. The small dirt particles finally became dirt chunks stuck to the bottom of the oil pan.
GM wanted no chance that a chunk or clot of dirt might be drawn to the pump. Thus, oil pulled into the pump had to pass through this screen.
These photos show several early screens used by various Chevrolet six cylinder engines. Note the used screen on the 1937-53 216 engine. Its rounded screen is held in place by a single wire. The wire can easily be unhooked from the housing. The screen then drops out for easy cleaning.
|1937-53 wire holding screen||1937-53 wire unhooked to remove screen|
An Inner-Line oil filter from Long Island, New York! Rarely seen today but a popular early aftermarket option. It secures to the engine block after removing the oil distribution cover. No oil lines. No moving the horn forward to make room for the intake manifold mounted oil canister.
Rebuilt Speedometers for Chevy Trucks & GMC Trucks
When your older truck needs a rebuilt speedometer, think of us! Our company, in combination with a local specialized shop, provides a quality product that you will be proud to place in your vehicle.
With most new repair parts, no longer available, we obtain used speedometers from across the country. Only the best parts are removed. These are combined with available new components to create a quality finished product. The following photos show various stages in the repair process.
It is very unusual that we are asked to create a 1954-55 GMC gauge panel. Our customer had lost his due to an un-professional rebuilder and was in a panic. We finally were able to create this set after an involved hunt in our various storage locations. What a job! All needed complete rebuilding and appearance upgrading.
We thought this should be on our Tech page to show their original new appearance. After all, we may never find parts to rebuild another.
This new steel center hub extension includes eight long bolts to reach the original wheel studs. This holds the factory wheel in place and then provides a threaded end for the original eight lug nuts which are holding another matching wheel.
The buyer of this aftermarket kit just had to be sure his new outer tire was the same height as the original inner tire.
Pictures and data from Scott Golding, Stratton, NE.
It is very important where to drill the hole for the new radio antenna. The results of making a slight mistake will stay in your mind for many years to come!
Radios during these 1947-54 Advance Design years were never installed at the factory. This was done by the authorized GM Dealer. In the box that contained the new radio was a paper template that prevented mistakes when drilling the antenna hole. This hole in the cowl was so close to the belt line that the body to the antenna seal gasket even lacked an edge where it touched this body belt. Even with GM moving the antenna so close to the belt line there is still only about 1/2″ clearance to the hood when it is open. See photo.
The sad realization occurs later when a new radio antenna is installed by an amateur. He drills the hole in the cowl (correctly on the driver’s side) about another 3/4′ forward. He smiles as the radio works great. He doesn’t smile a week later when he tries to raise the hood to check the oil. It won’t raise! The rear hood edge hits the antenna. A rubber plug later put in the new hole is always a reminder of what a 1/2′ can do.
|Hood Closed||Hood Open||Hood Open|
Over the many years we have collected a wealth of knowledge working with Chevrolet and GMC trucks from the years 1934 – 1972. We have gathered our Tech Articles, write-ups and how to’s and divided them into categories. You will find a list of helpful Articles that will help you get your old truck looking and running like new again.
Jim Carter Truck Parts….
Your #1 Source for 1934 – 1972 Chevy & GMC Truck Parts!
One of the most unique GM body styles is the famous COE (Cab Over Engine) design. By placing the cab over the engine of a large truck the wheel base could be shorter. This allowed the same maximum payload to be carried in a shorter truck.
These became quite popular in crowded downtown deliveries. The COE truck could turn in a shorter radius, on tight corners, iin narrow alleys, and still carry the same payload.
- rougher ride for drivers
- engine maintenance more difficult
- cab interior was hotter in summer with engine under the cab
- The driver and a passenger did not slide on the seat to get into the cab. They used two steps and a special hand grip to climb up and gain access to the cab interior
Click images to enlarge
|1946 Chevrolet COE||Owned by: Jim Cadorette 1946 with 2000 6.5 turbo diesel with 4 speed Over Drive|
|1951 COE||1940 COE||1940 GMC COE||1947-1955 Fender Pad|
|Owner: Koos Diedel from the Netherlands…1950 Red, 3 years to make it more “Freeway” friendly. Buick V-8, Air ride & so much more…”1951 Black – Bone Stock”||1939-1946 COE grab handles (to pull yourself up into the cab)||1939-1946 The left 2-leg mirror arm attached to the door.||1941-1946 Close Up – COE Grill|
|1947 – 1950 GMC COE
9 foot 1 ton 1947- 1953 pick up bed on a modern chassis.
|1947 – 1953 COE||1941-1946 COE Steps, To get into the Cab…|
|Starting a COE restoration from the ground up.|
1940 Chevrolet COE
The Restoration Begins 1950 COE
Bet you never saw one of these! A 2 ton truck you can park alongside all the automobiles in a shopping center parking lot.
This one of a kind 1952 COE truck is owned by Tim Tawney of Emmett, Idaho. He found it for sale three years ago and it was love at first sight. Its frame had been shorted to an unbelievable 91”. This is about the size of an early Volkswagen Beetle. Though 60 years old, it still has its correct wheels and 235 low pressure six cylinder engine. The paint, believed to be about 30 years old has the aged patina look that only time can create.
One of the trucks most unique features is the tow rig secured to the small frame extension behind the cab. It was manufactured by the Weaver Tow Company in 1918. This is a “2 speed hand crank” unit so the driver must manually operate the lever to lift the auto before it is pulled. Those were the days!
Tim is only the fourth owner. Fortunately, the 12’ door on his home garage allows for a place it can be kept in very bad weather. Where does he use this COE? Of course, Tim drives it to work every day at a local auto parts store. It must attract more attention than the sign on the building.
The Tawney Family has a name for most of their vehicles and this COE is referred to as “Stubby Gus”. You can contact Tim by email at: Tims70@hotmail.com or Facebook at: Stubbygus@facebook.com.
One of the most unique GM body styles is the famous COE (Cab Over Engine) design. By placing the cab over the engine of a large truck the wheel base could be shorter. This allowed the same maximum payload to be carried in a shorter truck.
These became quite popular in crowded downtown deliveries. The COE truck could turn in a shorter radius, on tight corners, in narrow alleys, and still carry the same payload.
- rougher ride for drivers
- engine maintenance more difficult
- cab interior was hotter in summer with engine under the cab
- The driver and a passenger did not slide on the seat to get
into the cab. They used two steps and a special hand grip to climb up and gain
access to the cab interior
Go To – Page 2 COE Trucks
1946 Chevrolet COE, Billy Marlow (all above) Read Billy’s Story..click here
|1948 Owner Ken Wedelaar, Midland Park, NJ||
1954 Owner George Coe
|1951 …Owner Jim Carter, Independence, MO|
1940 Owner, Unkown
|I found this 1946 COE in Fall City, WA and it is now in Soldotna, Alaska. I shipped the truck From Tacoma Wa to Anchorage Alaska on Totem Ocean Trailer Express (TOTE). I have driven it about 500 miles since I bought it.
COE Salvage Yard
1941 – 1946 for Parts
1946 for Parts
1940 Unknown Owner
|Three clear seal beams on a 1946! What could have been the purpose?||1941-1946 GMC owner unkown||1938 GMC COE…
Owner Jim Raeder
1954 Chevy COE
Cab Over Engine….Chevrolet Ugly Truck
If you would like your Chevrolet or GMC Cab Over Engine featured on our website, please send us an email along with your name, year, make, and model of your truck along with your photos. You can email your information by using our contact email form…click here
We don’t care if they are Ugly!!!
Another fine example of an old
Article courtesy of Rob English (firstname.lastname@example.org)
The issue of multiple piece rims and safety comes up frequently. There seems to be a quick rush to judgment about any rim that has more than one piece, and while certain types of multiple piece rims have indeed been outlawed and are no longer made, many others are not only still in service, they are still made new.
1947-1954 light duty trucks offered split rims in 1/2 ton (optional only) up to 1 ton trucks. Many people are unaware that there was a 1/2 ton two piece 15″ six lug rim option available in GMCs and I presume Chevy too. More often than not, we run into eight lug two and three piece rims on 3/4 ton and one ton trucks and these are the subject of most of the misinformation.
There were two types of split rims offered originally a 3/4 ton GMC; 15″ TWO piece split rims (Kelsey-Hayes type WK-3), and optional 17″ THREE piece split rims (Kelsey-Hayes type WK-4)
The two piece split rim uses a lock ring that is fixed and is one solid piece. There’s a notch in the rim where you can remove and reinstall the bead retainer ring while mounting and breaking down tires. To remove, you tip the ring at an angle and then slip it by the notch. To mount, do the opposite. This type DOES NOT require prying apart the ring and if you try to pry it off, you’ll ruin ix
The 17″ split rims originally would have been the Kelsey-Hayes type WK-4 and are three pieces; the rim, the bead ring, and the lock ring. They are put together pretty much the same way they do now-a-days on big truck rims. The tire goes on the rim, then the ring slips on and then the third ring is “zipped” on/off using a sledge hammer and pry bar.
The safety of these rims is directly dependent upon their overall condition. I have split rims on all three of my vintage GMCs. You will find knowledgeable truck tire places will work on them without hesitation and car tire places will go screaming in circles with their hair on fire spewing misinformation about “suicide” rims which may or may not be applicable, but does more to spook people than inform them with facts.
I have many many miles on my original split rims and find them to be great for my purposes. Others may have different views of what works for them. See the illustration below to understand the three basic types of original stock rims you’ll find on the old GMC trucks.
View PDF Chart of 1947-1954 Split Rims Click Here
Jim Carter follow- up on this article by Rob English:
I have three 1 to 1 ½ ton Chevy’s that were restored at least 10 years ago. They all have the correct split rim wheels. There has been absolutely no problem with any of them.
The tire quality in today’s world is so superior to that of 50 years ago! In the 1950’s I would see someone on the road changing a flat tire almost every two weeks. Now, it has changed to about once in 6 months.
Suggestion: To improve the appearance of your split rims, zinc plate (like GM did when new) or paint the small lock ring silver. This will nicely contrast with the painted wheel. You might say they even look a little like white walls! It really helps the appearance! See photos.
|1 ½ and 2 Ton||¾ and 1 Ton|
Purchasing a 1947-1953 optional cigarette lighter assembly from some vendors provides reproduction that is far from original in appearance. A manufacturer recently offered the optional lighter assembly but used a knob from the headlight of a 1947-1953. There is no similarity to the real lighter!
Don’t be embarrassed at a show where your vehicle is being judged.
Image of original (above)
Prices of more valuable metals such as copper and nickel reached their height during mid 1951 through 1953. Though U.S. shortages were much less than in WWII, there were price increases in the market that affected the financial bottom line of auto and truck manufacturers.
America almost demanded chrome on cars even if it raised prices. Decorative shiny trim was almost necessary to get buyers into the showroom.
Trucks were a different story! They were work vehicles. Eliminating the chrome extras did nothing to lessen the load capacity or operations off road. To keep the price down GM and other truck manufacturers removed much of the chrome and replaced it with paint. The steel stampings were the same, they were just painted. It was very necessary for GM’s base model to be priced low. City, county, federal, and many companies bought fleet trucks that offered the lowest price. Purchases had little to do with appearance. Even a $10.00 savings could make a sale.
The noticeable changes on GM light trucks is the lack of chrome on hub caps, grill bars, bumpers, and even the wiper knob. Stainless steel also felt the Korean War shortages. The deluxe five window pickup cab no longer had the stainless around the windshield and side windows. The glove box as well as the radio speaker horizontal trim was now painted steel. The deluxe panel truck with all its extra stainless side trim was now history.
By 1954 the chrome and stainless was back stronger than ever though some base models were kept in paint to hold their price low.
The following photos show just a few examples of GM’s Korean War era trucks. Considering their uses it doesn’t look too bad.
The 1955 year put Chevrolet on top! All stops were removed in announcing and continual advertising of the totally redesigned passenger car and their first V-8 engine. Television, radio, news papers and dealers regularly told the public that Chevrolets best year had arrived.
It was not good timing to also begin an equal advertising campaign for the totally new truck that was ready for manufacturing. A good business decision by GM was to wait about six months until the car ads had slowed, then advertising could begin again for their redesigned trucks. This would hit the customers twice in one year on major changes in the Chevrolet market.
It was unheard of for GM to not introduce a new Chevy vehicle each year, therefore at least something had to happen with trucks at the beginning of the 1955 model year. The answer was later called a “First Series 1955″. Chevrolet would introduce the 1955 truck by making several changes to their pre-existing 1954. With the new “Second Series” only months away, little investment was made to the early 1955 trucks.
First Open Drive Shaft
The most noticeable change on the popular 1/2 ton was the first open drive shaft in Chevy’s truck history. This was actually created for the later 1955 trucks but with dealer demand it was moved up to be in the early body style. This major drive line change required a different 3 speed transmission, rear leaf springs, shift linkage and shift box.
1955 Hood Side Emblem
The outside visual changes were minimum. During the about 5 months production, the 1955 early truck was given totally different hood side emblems. However, to reduce costs the number portion of the emblem could be changed depending on the size of trucks. Example: 3100 on 1/2 ton, 3600 on 3/4 ton and 3800 on the 1 ton.
A no cost difference was changing the vertical stripes on the front hood emblem from red on the 1954 to white on the 1955
The paint arrangement on the non-chrome grill was also a non cost change for Chevrolet. The grill bars were changed from body color to white.
Interior paint (again a no cost change) was slightly modified from a pearl beige color 1954 to a light metallic brown.
Thus, with little extra investment Chevrolet had a new truck for the beginning of 1955. This was the final offering of this body style that began in 1947. GM referred to it as the “Advance Design”. It has become one of Chevrolet’s all time greats. It’s popularity today is as strong with hobbyists as it was with new buyers 50 years ago.
Then came the totally re-designed trucks in mid-year 1955. That will be another story!
This was one of the most unique years for General Motors trucks. The Korean War and some resulting material shortages were now history. The economy was growing and the average worker brought home more wages than ever before. Sales of luxury options on automobiles were showing definite increases.
To capitalize on this trend for transportation improvements, GM was fast working on total new automobile and truck models for the coming year. When introduced, the result would be record sales which put General Motors even further above it’s competitors.
But what about the 1954 year for GM trucks? Waiting buyers had the demand for a new updated truck but the tooling was not yet complete. Other competitive truck manufacturers were beginning to offer many deluxe features.
Therefore, General Motor’s 1954 answer to temporarily satisfy new truck buyers was a major facelift of the prior models. To keep costs down, GM continued to use the basic cab introduced in mid-1947. To update this seven year old design, an enterprising engineering department added items such as a one piece curved windshield, completely redesigned dash board, and created a totally different grill. All this while keeping almost identical hood, fenders, bumpers, running boards, seats, doors, etc.
Another big first for 1954 Chevrolet truck cabs was the optional color coordinated interior and the two tone exterior. This had never been offered before by GM on truck cabs. Advertisements defined it as “The Bold New Look”. For an extra cost (only on cabs with rear quarter windows), the customer could order interior color combinations including two tone blue, gray and maroon, two tone green, plus dark and light brown. Each of these four base color combinations were harmonized with the headliner, floor mat, door panels, windlace, and interior sheet metal. Pearl beige was the standard color on non optioned cabs.
This deluxe two tone interior package was introduced in mid year. Therefore, it is not shown in early 1954 Chevrolet truck brochures and many perfectionists do not know it was available later.
The two tone exterior paint option included a white top only (shell white) and only on the deluxe cab. For the short run in 1955 of this body design (first series), the two tone was still with only a white top but the shade was changed to Bombay Ivory.
With fears of Korean War shortages now over, chrome and stainless steel could now be offered again as part of a long option list. On the deluxe model this included stainless exterior window trim plus chrome hub caps, grill and bumpers.
The option list also increased greatly for the 1954 year with new items available not offered during previous years. Examples were full wheel covers, electric wiper motor, automatic 4 speed transmission, ride control seat, day-night inside rear view mirror, etc.
It is also important to remember that for 1954, Chevrolet chose to introduce two major items and not wait for the totally new later 1955 models. This was the high pressure insert bearing six cylinder engines and the deeper restructured pickup bed. Thus, the 1954 shares both the early and late features and is a true “transition truck”.
At present, the 1954 GM light pickups, particularly the deluxe models are showing a fast increase in popularity among restorers. They stand out as a unique transition truck having various characteristics not associated in total with any GM commercial vehicle. It is felt their future pricing will also stay higher than either 1947 to 1953 or the 1955 to 1959 models in equal condition. Of course, all older GM trucks are on their way to the top in popularity and value. They are to restorers “the Model A’s of a New Generation”.
Tech Tip from Ron Hansen
Alignment Solution for Installing a Late Model Rear End in a 1947-1954 Pick Up
On the original rear end, the spring centerbolt is offset to the front of the spring by 2″to 3″. If you install a modern rear end (with an open driveshaft) and retain the original springs, the wheels will end up offset forward (inside) of the original wheel openings in the fenders. To correct this problem, remove the original springs and reverse them end to end (front to back) as they are the same on both ends. This will bring the spring centerbolt to the rear of the axle and place the new rear end in the center of the fender wheel openings.
Click to enlarge
GM trucks titled prior to the mid-1950′s were usually registered using the stamped engine number not the body digits pressed in the door ID plate. This practice has created many problems in later years as states became stricter in titling.
Unfortunately, many older vehicles outlast their engine and owners rarely rebuild the originals. To save time and certainly expense, a rebuilt unit or a used one from another vehicle would often be installed. This worked great until years later when state safety inspections began or the vehicle was sold out of state. With a prior engine transplant, there was no ID numbers that would match the title.
Even today, this problem occurs as older trucks with different engines are pulled out of barns and from the property line of a farmer’s back field.
On 1937-55 1/2 and 3/4 ton rear bumpers there exists an unused center square bumper bolt hole that sometimes brings up questions from restorers. “Why does this hole exist and what is it purpose?” The answer relates to the attitude toward trucks during those years. They were for work and keeping their production cost low was a priority.
The bumpers during 1937-47 were the same front and rear. The center hole at the front held a vertical steel bracket which was needed if the truck was hand cranked. Rather than make a 4 hole rear bumper, GM simply used their front on the rear. Even in 1947-55 with a slightly different horizontal shape, the factory 5 hole punch was used on front and rear. Therefore, the rear bumper hole has no purpose. To cover this hole, GM produced a special bumper bolt that has become very rare. To save costs (it is a surprise that anything was used) GM created a one inch long stud held in place with a sheet metal speed nut. It has no threads and its head is covered with a stainless cap so it looks like the other bumper bolts from a distance.
Most of these original rare filler bolts will have dents and scrapes on the stainless cap. A skilled person can place a new stainless cover from a more common replacement bolt and make this rare unit look like new.
Of the many differences between the Chevrolet and GMC 1/2 ton during the early years (1936-54), the GMC offering of a long bed pickup box was one of the more noticeable. Only GMC provided this option. To obtain this extra bed length on a Chevrolet, the buyer ordered a 3/4 ton.
This difference existed with the first GMC pickup in 1936 and continued through the end of the Advance Design series in 1955. Possibly the reasoning for this was the horsepower difference between these two marquis. The base 216 six cylinder Chevrolet engine provided 92 hp. The standard 228 GMC six boasted 100 hp.
To get the approximately nine inch extra GMC chassis length not only were the two frame rails longer but the drive shaft was extended. GMC engineers did this by developing an extension which was the connecting length between the standard short bed closed drive shaft and the rear of the transmission. None of this interchanges with a Chevrolet and both makes use a totally different drive shaft design on their 3/4 ton series.
The adjacent photo shows this unique connector link installed in its GMC. A 7 3/8 inch steel jack-shaft is surrounded by a cast iron housing (it is still a closed drive shaft) and includes an extra u-joint, bearing, and seal. Though, a strongly built drive shaft system, this portion becomes the long bed 1/2 ton’s weak link after 50 years of use and abuse. Without a doubt this link has performed almost flawlessly beyond the miles expected by its designers. However, it does have its long term limitations. The many prior miles, lack of regular maintenance, and occasionally overloading the truck makes the failure of an original in today’s world a definite possibility. Watch for sources for the rare replacement parts in this connector link just in case. Otherwise surprise damage in this area can keep your GMC 1/2 ton long bed out of service for quite some time.
When you would like to restore your truck and no workshop is available, there is a solution. Most all the repairs can occur in a temporary shop and at a very low cost.
Jim Valano of Marion, Indiana is a true example of ‘American Ingenuity.’ He purchased a ‘canvas storage tent’ and assembled it at a convenient location. He even made the floor using the backside of used carpet on top of sheet plastic. Its roll-up sides are adjusted for the weather.
Jim’s 1957 Chevrolet ½ ton is now almost restored and most of the work occurred in this canvas enclosure. It can later be removed and stored in the original box.
If you need a building for your restoration, this may be your answer. Just check with your city for possible zoning restrictions!
The body I.D. plate – every GM truck had one attached at the factory. Basically it states the vehicle’s gross weight limit (weight of truck plus its maximum allowed load) plus stamped digits that give the assembly plant year, size of truck, month built, and sequential numbers as it came off the production line. These plates are necessary for positive vehicle identification.
A unique characteristic of the 1950 and older GM truck is that the I.D. plate was not riveted at the factory but rather held in place by two small clutch head screws with a hexagon perimeter. Thus a wrench or a clutch driver can tighten or remove them.
Over the years if the two screws begin to loosen, the owner would either retighten them from time to time or often remove the plate for safe keeping. Usually this plate stayed in the glove box or at home and just never got reattached. Thus we find some of these pre-1951 GM trucks with no I.D. plates. In the early years this was often of little concern as most trucks were titled on the engine number.
After 1950 these I.D. Plates were riveted to the door post. Probably not so much to prevent vehicle theft (we lived in a different era) but just to keep them from being lost.
In today’s world this can cause big problems in registering particularly if the transfer is to another state and an I.D. number verification is necessary. Even if the I.D. plate remains secure with screws as it left the factory, a problem may still exist. Unfortunately most inspectors today weren’t even born when these trucks were built. Sometimes an officer refuses to OK the truck, saying that I.D. plates do not come with attaching screws and it is not legal. You now have an uphill battle with an inspector that really believes he is correct.
Yes, you can attach this original scratched and painted-over I.D. plate with rivets. However, what is this inspector going to say when he sees this worn and painted on I.D. plate attached with two new shinny pop rivets? Have you ever been accused of car theft? It is then you wish the truck was titled to the engine!
Remember, on a left hand drive truck (1947-55) the I.D. plate attached to the left door post. It is attached to the opposite side on the right hand drive truck. The two holes for the plate screws or rivets are punched at the factory in both door posts.
To keep the 1947-1955 GM trucks base price low, their 6 volt cigarette lighter was a dealer accessory. The vehicle always came from the factory with a round blank out plug at the lower center of the dash.
To save tooling costs both the Chevrolet and GMC truck divisions used the same lighter as was found in Chevrolet’s passenger car. It did not match other knobs in the cab. Its double ring chrome head is exclusive to General Motors though it does not carry their logo. They are often seen at swap meets and flea markets mixed with lighter accumulations from all makes. The chrome head is easily unscrewed when a replacement heating element is needed. It will attach to either a 6 or 12 volt element. The in dash receiver also must be changed. GM made a slight difference in element diameters so 6 and 12 volt units could not be accidentally mixed.
1954-1955 Example (above)
In contrast to 1954-1955 Chevrolet trucks, the same year GMC had a position in the dash for an optional gauge. It was here that larger GMC’s had a tachometer or vacuum gauge installed. The 1/2, 3/4 and 1 ton GMC’s usually did not require these engine gauges and a blank-out plate is normally found there. An option here in these smaller trucks is a spring wind clock. It was produced by General Motors and installed at their GMC dealerships.
1954 GMC dash with clock installed (above)
To save production costs, GMC used the clock that was already on the 1953-1954
Chevrolet car. In this way, their investment was limited to a chrome adapter ring that fit in the opening that held the blank-out plate.
This chrome ring has recently been reproduced and is available from most full stocking dealers including Jim Carters Truck Parts. Restorable 1953-1954 Chevrolet car clocks are found at most any medium size automotive swap meet.
There couldn’t be an easier place for a tree to grow. If you don’t move your truck for a few years, trees will find it. As they grow wider, the truck bends to fit!
Here no one steps on a tree at the beginning. Lawn mowers can’t reach it.
It’s free to grow.
With the introduction of the Advance Design Cab in 1947, a new dealer installed heater also became available. When used together this new body was referred to as The Cab That Breathes.
All U.S. manufactured Advance Design Cabs had a row of louvers on the right outer cowl which allowed air to enter the cab interior with the help of the new optional fresh air heater. It was a great improvement over prior years!
As air was brought in from the outside it passed through the heater core. This warmed air usually held less humidity than air inside the cab due to the breath of passengers. The fresh, dryer, air helped prevent the inside of the windows from fogging during very cold days, thus GM said the cab breathed.
This excellent heating system was made even better in 1953 with the introduction of the revised airflow heater. By pulling a knob, at the left of the steering column, a door inside the heater would cover the outside air intake. Now the heater was of the recirculator design. It pulled air from inside the cab so that inside air was re-warmed. Yes, humidity did accumulate quicker and windows could fog but heating the air inside was faster on a cold morning.
Note these pictures of the improved 1953-55 fresh air heater. The driver operated cable was pulled and a door inside the heater shut off outside air. At the same time, a one inch wide door on the case opened to allow recirculation of air to occur. A non-related lever on the case directs the heated air to the floor or above through the defroster ducts.
This ingenious idea by GM engineers now allowed the driver to have a cab that breathed or one that did not.
Hand operated defroster lever, cable for intake door, and the water flow adjusting knob (above)
The knob at the left of the steering column for pulling the cable (above)
The main heater attached to the right inner cowl panel (above)
Side view of heater with water control rod in foreground (above)
A close up of the one inch intake cable operated door on the heater case (above)
Marty Bozek, Lutz FL.email@example.com
Pat Jackson, Johnstown, OHredchevy38@embarqmail.com
By the mid 1950′s extra income in the U.S. was creating an increased demand for accessories on both cars and trucks. To take advantage of this, the Chevrolet Truck Division introduced one item as a first. It would not appear again on Chevrolet trucks until the mid 1970′s.
The new accessory was the 1954-55 dash mounted clock. To offer the most with the least investment, only the die cast housing was new. The clock was already an accessory on the 1953-1954 Chevrolet car. By combining the two, dealers could market a clock accessory to new Chevrolet truck buyers. The housing was even painted pearl beige to match the 1954-1955 Chevrolet truck interior color.
It fit between the two dash bezels. A paper template was in the box so the dealer’s mechanic or the owner would drill the mounting holes in just the right place.
The housings are not being reproduced. They are in high demand among 1954-1955 Chevrolet truck restorers so the retail prices just keep rising. If you do locate this housing, the correct clock is not difficult to locate. They were on most 1953-1954 Chevrolet cars.
Prior to the 1960′s, trucks were used as work vehicles. On Friday nights, most were parked for the weekend and the family sedan was the transportation vehicle.
It was a conservative era when you bought only basic necessities. A $5.00 grocery purchase was more than most could carry. Finding white wall tires on a truck would have been a rare sight, indeed. Very few cars, except for most luxurious models, would have had white walls even as an option. It should be remembered, that most roads, except highways and those in the main part of town were gravel, dirt, or sprayed annually with tar.
Of course, a dealer would have been happy to install aftermarket white wall tires, if the customer made a specific request. For a price, the dealer would provide any option to keep a satisfied customer and make a few dollars.
On GM trucks, white walls became a factory option in mid-1955, partially because of the introduction of the Chevrolet Cameo and GMC Suburban carrier and also due to more roads becoming paved. These very deluxe pickups, as well as several of the other well appointed 1/2 tons justified a white wall tire for those wanting it all!
Almost none of these deluxe models would have been given their second set of white wall tires. By then, the pickup was older and being used more as a hauler, not for appearance.
The 1947-1955 Chevrolet and GMC came from the factory with left mirror arms on left hand drive trucks. This was particularly important if the truck was to have a large bed that covered the rear window.
To keep sale price low, the right mirror arm was an accessory (dealer installed). It was very important that the dealer place the mirror just right so the actual mirror was viewed by the driver through the lower right corner of the windshield.
To prevent dealer mistakes, GM placed an inner panel in all trucks covering the area were the two holes would be placed. This panel had factory holes, showing the mechanic where to drill. Thus, two exterior holes could always be in the proper place. Yes, the glove box liner would be removed to make room for the drilling.
Inner panel guide for drilling (above)
Outer panel before drilling (above)
It’s surprising that an item placed on almost every 1947-55 Chevrolet and GMC truck has become so impossible to locate. Most collectors have never seen one!
The product is the five inch GM round mirror head. It was originally bolted to the cowl mounted mirror arm on the driver’s side. They were always black and had the pivot on the outside (most round similar non-GM mirrors have the pivot inside the housing).
The pictured mirror head is New Old Stock. Even the zinc plating, which reduces rust, is perfect. The acorn nut can be tightened just right so the head is still hand adjustable yet will stay in place on rough roads.
If almost 500,000 Advance Design trucks were produced each year between 1947-55, where are the original mirrors? The answer relates to the use of the vehicle. These trucks were made for work! Few were garaged. After several years of weathering the mirrors were in need of replacement. This was an easy do-it-yourself exchange and most owners could pay less for aftermarkets at an auto parts store or service station. Few genuine GM replacement mirrors were bought and thus the dealer kept very few if any in stock.
The Chevrolet dealer installed recirculator heater was much different in 1947-48. In 1946 and older plus in 1949 through 1957, they sold the traditional round core design but for 1947 and 1948 it was all different.
The attached photos show the 1947-48 GM recirculator heater. Its rectangular core and vertical mounting studs are reserved for just these two years. To be sure the dealers mechanic installed these accessory heaters correctly, holes were placed in the firewall during the trucks construction.
In this photo of a 1948 firewall, arrows point to the factory holes to make sure the heater is installed just right.
An additional point of interest on this 1947-48 heater:
The defroster appears to be an extra cost item. Note the picture of the truck with the side mounted defroster. Also see the separate heater with a round factory plate covering the defroster position. It appears you could order a style of recirculator heater depending on the climate in your area.
No less than three different mirror arms were used on Advance Design Trucks (1947-1955). Though most vendor catalogs do not reflect these differences, the following should be of interest to those that want their truck restored correctly.
All left mirror arms attach to the same position on the cowl, however two designs were used. In the beginning years (1947-50) the arm pointed at an upward angle. This was much like earlier GM truck body styles between 1936 and 1946.
A change in design began in 1951 with the introduction of door wing vents. With the vent and door open together the mirror head could be hit and broken. Thus, a more horizontal arm was designed and it lowered the mirror. The rounded corner of the wing vent frame could no longer touch the mirror glass.
The right side cowl mounted mirror arm was a dealer installed accessory. Because of the limited space on the cowl (between the door and hood) it was necessary to place a curve in the arm. This brought the mirror head forward so that it could be seen through the lower right corner of the windshield.
1947-1950 Left (MI108) (above)
1951-1955 Left (MI109) (above)
1947-1955 Right (MI125) (above)
We often get requests for a formula to make the Advance Design pickups more freeway friendly. Their original ring and pinion gears were created to make the truck’s six cylinder work well with a load and also keep up with the 1950′s traffic on gravel roads and two lane paved highways.
Though a higher speed reproduction ring and pinion was introduced several years ago, some owners still ask for another alternative to get in the “fast lane”. One method has been used successfully for several years and requires most parts from local salvage yards. Obtain the Borg-Warner 5 speed overdrive transmission from an S-10 pickup. It must come from an earlier model with a mechanical speed sensor (on the side of the case). It can not have the more high tech electronic speed sensor as used on the later S-10 pickups with computers.
This transmission will bolt against the original bellhousing of a 1948 and newer (a nice surprise). The clutch shaft which extends out of the front of the transmission is usually too long to allow the ears to bolt flat and secure to the bellhousing face. Therefore, if this occurs, shorten the tip of the shaft about a half inch and all will fit together. This is a must. Otherwise you can even break off a transmission ear when you begin tightening the four attaching bolts.
The ears that attach the transmission to the bellhousing are usually drilled for a metric bolt. They will need to be enlarged for a standard 1/2 inch bolt as is threaded into the bellhousing.
The V-8 Camaro 5 speed transmission is also similar to the S-10. It is said to not be as low geared and this makes it more desirable. The Camaro shift lever is too far back for the 1948-59 pickup. The bench seat is in the way. To correct this, use the S-10 tail shaft housing and case top cover. This will allow the vertical lever to come through the original floor in the correct position.
The input shaft of the 5 speed will have either 14 or 26 splines. Therefore, the clutch disc must match the transmission and not the 10 splines from the original 1948-1959 truck.
The attractive S-10 boot is still available from GM and the shift knob of choice is from a late model 5-speed Jeep. It screws on perfectly and looks great! The S-10 shifter clears the seat cushion and looks like it was installed by GM.
The next step is the differential. An open drive shaft style will be necessary to match up with the 5-speed but this is a subject for an totally different technical article.
The result of this change is lower RPM’s and speed to keep up with traffic flow on most modern highways.
On the new 216 six cylinder engine, introduced in 1937, the vacuum advance was placed on Chevrolet trucks and cars at the right side of the engine below the distributor. A small metal vacuum line across the front of the engine connected to the carburetor base.
This vacuum advance design continued on trucks through the end of this family of six cylinder engines in 1962, however, on cars a change occurred in 1952. For cars, their engines began with new side motor mounts, not at the front of the block. For the vacuum line to get around this side mount the advance assembly changed position. See photo.
Note: When you see a parts book showing the vacuum advance changes in 1952, they are describing a car not a truck.
Using the 1952-1962 car vacuum advance on a truck will require modification on the vacuum line to a different bend. It will definitely not look correct!
1937-1951 Car and 1937-1962 Truck (left) | 1952 -1962 Car – (right)
The Trials and Tribulations of Installing a GMC 302 engine into a 1950 3/4 ton Chevrolet Pick Up
by Joel Baumbaugh
Background: About 5 years ago I “upgraded” the engine in my truck from a 216 to a 235. Lately I have felt that I wanted/needed a little more torque (especially while the bed is full of something heavy) and while one option was to rebuild and re-cam my 235 and another was to install a Chevy 350/400 (or 700R), the “popular” literature said that I could also install a GMC 270 or 302. Just to be “different”, I decided to go the latter route.
The Source: I wanted a “running” engine that I could just drop in with a minimum of trouble. The engine I found for my project was a 1959-1962 GMC engine from a School Bus. The bus had been converted into a “camper” and had then caught on fire and burned beyond repair. At first glance, the outside of the engine looked kind of rough. I checked the compression (all cyls. were at 160 lbs./sq.in), looked at the plugs (all light brown), listened to it run (no strange noises) ‘ the oil pressure was 55-60 lbs./sq.in. at idle and the rocker arms/valve area was pretty clean of sludge. Short of pulling the pan, this was as far as I could go. I bought it, brought it home and cleaned it up.
Problems/Solutions: The engine had a LOT of bus-type accessories that I did not want/need. The “massive” front Crank Pulley (the damper pulley assay) had a three-groove pulley ‘ “way” too long! After careful measurement I found that I was able to replace it with a single groove pulley off of a 235 (I replaced the front seal at this time). The water pump shaft was “very” long as well and sported a 2-groove pulley. I removed the pulley and ground/cut the pulley shaft back. The water pump on this engine did not seal against the block and/or head. This one was bolted to a thick steel plate which held a tensioner (for a double groove pulley) which weighed about 30 lbs. (weight I did NOT want) and was bolted to the front of the block. I found a rear plate (and gaskets) for the water pump from a place here in town that rebuilds water pumps. Bolting the water pump directly to the block saved me another ½ inch in engine length. The owner also sold me a flange to press on to the shaft so that I could bolt a new water pump pulley onto the pump (the original Chevy is shaft diameter is ½ inches and the 302 is 3/l8 inches). To find a pulley which would align with the bottom crankshaft pulley required a number of trips to local junk/wrecking yards. I finally found one that was the perfect depth (I’m not sure if it was originally from a Chevy or not). I had to enlarge the center hole to make it fit the GMC shaft.
The 302′s “bus” generator weighed about 80 lbs. I found that the 235′s generator mounting flange’s bolt-holes fit perfectly! However, I “did” need to reverse it and then elongate the mounting holes so that I could slide it forward to align the generator pulley groove with the crank and water pump pulleys.
The carburetor that came with the engine was a joke. It even had a governor on it. I had the option to purchase a better 2-barrel carburetor or to step up a little bit and buy a 4-barrel manifold. I did the latter. I had a (gasp) Ford ‘Autolite’ carburetor in my garage (about 400 CFM) from a ’289′ which I bolted up to the manifold and it works GREAT! – Especially with the stock low-performance camshaft. I also at this time “upgraded” my carburetor linkage. I went to an off-road dune buggy place and purchased a new accelerator pedal and a push-pull cable. Configuring the carburetor linkage from the stock pedal to the new manifold/carburetor would have been a nightmare otherwise.
Radiator: The 302 engine “is” 1 1/2 to two inches longer than the 325 (which is longer than the 216). This means that the radiator no longer fits into its original location. I tried to modify the radiator mount to put the radiator inside. Don’t even try. The radiator needs to mount on the front of the mount. This means that you will have to borrow your neighbor’s “Saws-All” with a metal cutting blade and cut away the top and front cross bracing on the radiator support, the lower front wind deflecting metalwork at the bottom (behind the grill) and drill 6 new holes in the mount for the radiator. The upper support that contains the hood latch will need to have a rectangle cut in it to fit the top of the radiator in it as well. I now have about 2 inches clearance between my water pump pulley and the radiator. I use an electric thermostatically controlled (pusher) fan in front of my radiator. It’s quieter, doesn’t rob the engine of power (better mileage) and the water pump may last longer without the fan blades. Note: My friend and neighbor has a 1951 GMC. I have measured his engine compartment. From his bellhousing to the radiator flange he had 4 more inches to play with, so I’d bet that he originally had a longer GMC engine (he runs a Chevy 235 now), and that he could make the conversion to a 270 or 302 without any cutting being necessary.
Front Mount Yes the 302 engine “is” 1 1/2 to 2 inches longer than the 235. The front mount on the Bus’ 302 was a weird set-up which caused the engine to sit at an angle (like a Chrysler slant 6). This saved some height in the bus’ engine compartment. However, after removing the bus setup spacers, I found that the two bolt holes on the mount (on the bottom of the timing cover/block) were at right angles to the block and aligned perfectly with my truck’s original 216 mount so I was able to exchange them and everything was level ‘ no oil pan removal required! I then drilled two (new) holes through the truck’s cross member, put in longer frame-mounting bolts and added some extra rubber padding (cut from a truck mud-flap) to keep the mount from rubbing on the frame and so far its worked ok.
Rear: The bus engine I purchased was coupled to an automatic transmission. That meant that it had a flex plate (that the converter bolted to) instead of a flywheel. The flex-plate (with the old ring-gear) was MUCH larger than the flywheel I would need. I found a flywheel from a GMC 270 that fit. Although the flywheel’s diameter and the number of teeth are the same as the 1955-1959 Chevrolet, the crankshaft bolt pattern is different between the GMC’s and the Chevrolet’s. The flywheel bolts are different as well (1/2 inch dia. instead of 3/8′s”). Although I tried using an impact wrench, a gorilla on steroids must have put on the old flywheel bolts. I broke a socket and finally had to remove 3 of them with a chisel. The 3/8″ GMC flywheel bolts are not available ANYWHERE. I went to an industrial bolt supply place and bought six more grade 10 bolts. I had the heads machined thinner (like the originals) as otherwise they protrude into the pressure plate/clutch plate area and will cause binding problems. I then carefully shortened the bolts (watch those threads ‘ I put a tap on the inside of the bolt and then backed it off to remove the burrs) to match the original length as they otherwise hit the block behind the flywheel (close tolerances here…).
The pressure and clutch plates and throw-out bearing match those of a Chevy 1955-1959 10- inch set. The 302 had a roller bearing pilot bearing instead of a oillite bronze bushing. I replaced it with another roller bearing and the transmission (its a Saginaw off of a 1969 Camaro) fit in just fine.
I used my original bellhousing off of the 1950 Chevy. The old GMC one was slanted to match the front motor mount. The starter location in the GMC bellhousing was for a larger diameter flexplate and would not work. The GMC starter had the wrong number of teeth to work on the 10″ flywheel. The starter which (I found) works, was a 12 volt 9 tooth (for a 164 tooth flywheel) from a 1955 Chevrolet and works great.
Oil and Water lines: There is an oil line on the front of the block up to the head. This supplies the oil to the rocker arms. Leave it alone. I tied (T’d) into it and put on a 100 PSI oil pressure gage as my Chevy gage only goes to 30 lbs. This engine NEEDS an oil filter. If you block off the oil supply line on the driver’s side of the block you will not get ANY oil pressure in the engine. I “T’d” into the pressure side and connected up my original oil pressure gage (it’s a stretch, but it reaches). Yes, it’s always pegged on 30 lbs., but gives me a warm fuzzy feeling when I look down. The head has an external water line that goes to the thermostat housing. Leave it alone. You can put a “T” in and hook up your temperature gage (with an adapter), but I put mine further down on the block (there’s a fitting there), because it was always showing “cold” on the gage. Be careful of that temperature gage line. It cost me close to $50.00 the last time I had to replace it. The radiator hoses clamped right up although the GMC diameter on the lower radiator hose is one step smaller.
The 302′s distributor had a governor on it and was centrifugal advance only. The bottom of the distributor was different than the Chevy, but my Chevy distributor “guts” bolted right in. I was able to put in a spring kit (the GMC centrifugal advance springs were so thick that they could have been used for front struts on a Honda) and I now have vacuum advance as well.
The GMC fuel pump leaked so I replaced it with a Pep Boys electric fuel pump. I couldn’t find a replacement anywhere locally, so I guess I’ll have this one rebuilt for a “spare”.
I had a split cast-iron exhaust manifold on the Chevy 235. I “may” get a header for this motor in the future, but in the mean time I had the muffler shop split the 302′s three-inch header pipe into the two existing exhaust pipes.
And, how is it?
Well, pretty good. I have a LOT more torque. This means that I can get up to freeway speeds without wishing for bike-pedals for a little more push. I have 36″ tires on 6″ Chevy rims on the back so I’m only turning 2,800 RPM at 60 mph. The larger tires had made the truck a little “logy” getting started with the 235 ‘ now it “steps right out” from a light. I haven’t checked the gas mileage yet. I was getting 17 mpg City and 20 mpg highway with the old 235. I’d guess that I’ve lost about 2 mpg with this engine/carburetor combination.
Future When this old engine is due for a rebuild, I’ll probably buy some “lighter” pistons and a little hotter (than stock) cam. The pistons will help the engine “rev” faster, be easier on the bottom end and will probably result in higher gas mileage due to their weight difference and the higher compression. The cam will help volumetric efficiency and give me a little more torque and higher end. Of course I’ll have everything balanced ‘ IMHO it’s worth the extra money.
I hope that this story helps someone else. Remember the 270 and 302 are “basically” the same engine so I imagine that your situation will be pretty similar to mine no matter what you find. It took “6 hours” using hand tools to remove the old engine and 4 days to put back in the new.
Since the project above, I decided to rebuild the 302 as it was burning a little oil. I bored the cylinders out .125 thousands (it’s now 320 cubic inches), put in a “Patrick’s” M4F camshaft, and put in “Venolia” 10.5×1 forged pistons. I had everything balanced of course. I had to find and purchase another head as the old one had a crack in it (hence the oil burning). When I got the new (used) head, I pulled out the valves and cleaned/smoothed up the intake and exhaust ports/passages which were pretty rough castings, and then put in new late-model exhaust valves (I went to 1.5″) and hardened seats for unleaded gas, and I’m using Chrysler “440″ valve springs. I’m now running a “Holley” 600 CFM carburetor (vacuum secondaries) with “Fenton” cast-iron headers. When first started up on a dyno (and not really broken in yet) it recorded 286 hp and 362 ft/lbs torque; not bad for a “street” engine; At this time I also put in a T-5 GM transmission from a ’91 V-8 Camaro (the V-8 transmission has better bearings to handle the torque) with a tail-shaft from a S-10 Pick-up (the shifter was almost in the same place) – so now I have a 0.74 overdrive. At 75mph (a fender-slapping speed for the old pick-up) I’m only turning 2,100 RPM; I had a new driveshaft made as the transmission yoke splines on my old one looked worn.
So far, I’m pretty happy with my set-up. Happy “wrenching” everyone;. ..jb
During the Advance Design Truck years, two air filters were available when an order was sent to the factory. The base air filter (no extra cost) was the oil-wetted design from earlier years. The owner was expected to place a thin layer of motor oil on the filter media. Dirt particles would be caught by the oil as it passed through the mesh material. This metal mesh looks much like the material in a kitchen pot and pan copper scraper. The owner was reminded to clean the mesh every 2000 miles for it to be effective.
For an extra $5.00 an improved oil bath air filter came with the new truck. Most everyone who used their GM truck for work duties chose this filter. It required less maintenance and was more forgiving if neglected. GM recommended cleaning in kerosene each 100 hours or 5,000 miles minimum. Part of the filter media actually sets in an oil reservoir that has a pint capacity. The oil is slowly drawn up into the filter material and collects dust particles as the air travels to the carb. * NOTE: For best results use non-detergent oil. Dirt is not held in suspension with non-detergent oil and it settles on the bottom of the reservoir. At the same time held particles slowly sink toward the oil reservoir and accumulate at the bottom. Thus, this filter is always effective due to the oil upward movement. When the oil is changed in the filter pan or reservoir the dirt is also removed.
As with other manufacture’s air filters, they will cause fuel mixture problems when not maintained. A very dirty air filter will restrict air flow into the carburetor and result in increased fuel consumption.
Oil Wetted (above)
Oil Bath (above)
Oil Bath (above)
By January 1949 GM realized there was an engine noise in the new late 1947 Advance Design cabs that needed correction. If a truck customer complained, the dealer was given a solution by modifying a part from a Chevrolet car.
The problem was engine noise entering the cab through the horizontal accelerator rod where it touched the floor hole. On many early Advance Design models there was not yet a pocket to hold a felt floor seal and insulate this rod. Metal to metal contact was inevitable.
The enclosed article is from a GM product service bulletin issued January 31, 1949. It was sent to all dealers.
Note: It is doubtful if all this work required of the dealer in the bulletin was ever very successful. The real noise problem was actually from attaching the back of the accelerator pedal to the accelerator rod. Metal contact here brought noise into the cab and then to the floor where the accelerator pedal made connection. By 1951 a new pedal to rod connection was used (like the car) and the problem was corrected.
Between 1954-1962, Chevrolet produced their famous full oil pressure 235 cubic inch six cylinder in trucks and it soon proved to be one of the greats among engines. However, at the same time a lesser known “big brother” to this base engine was being used. This was the quality built 261 cubic inch six cylinder! This 261 was available only in 2 ton (6000 or C60 series) trucks and school buses. During it’s early years (1954-1957) it was an extra cost option above the standard 235 six cylinder.
In 1958-6192 (the 261 now had a full flow remote oil filter) it became standard in the 2 ton chassis up to 19,000 pounds gross weight. Above that Chevrolet substituted a V-8.
This larger six was not offered in US cars, however there was an exception in Canadian built full size Pontiacs. Their base engine, also produced only in Canada, was the 261 not the V-8 as in the US. This provided basic power, great dependability, and better gas mileage.
Basically, this larger engine was a 235 with the same crankshaft but GM engineers made various modifications to give it extra strength and horsepower. It’s standard bore diameter increased from 3-9/16 inches to 3-3/4 inches. The connecting rods were heavier and attached to increased diameter piston wrist pins.
Its higher lift cam shaft, for better breathing, was shared only with the early 235 six cylinder Corvette. A modified larger Rochester carburetor was also a 261 only feature. Unfortunately most of these larger sixes have long since had their original Rochesters replaced with 235′s and therefore do not perform to their full potential.
In pure big truck form the 261 has a larger thermostat housing holding a double acting thermostat. This is designed to circulate water through the block and head before the thermostat opens to allow hot water into the radiator. Thus, no internal steam hot spots during warm ups, especially in winter. This is particularly important with very cold coolant. Vital engine spots can become very hot before the total coolant becomes hot enough to open a normal thermostat on the front of the block.
|6 Cylinder Engines||Jobmaster||Thriftmaster|
|Displacement||261 Cu.In.||235.5 Cu. In.|
|Bore||3 3/4″||3 9/16″|
|Stroke||3 15/16″||3 15/16″|
|Compression Ratio||7.8 to 1||8 to 1|
|Horsepower||33.7 (AMA) 148 (Rated)||30.4 (AMA) 140 (Rated)|
|No.of Main Bearings||4||4|
|Wrist Pin Diameter||.927 inches||.875 inches|
|Rod Shaft Thickness Front to Back||.595 inches||.595 inches|
|Rod Shaft Thickness Side to Side||.975 inches||.760 inches|
|Crankshaft Journel Diameter||2.435||2.435|
|Engine Color in trucks||Green -some later Yellow||Gray|
The block and head surface have three pair of matching small “steam holes” that allow any steam hot pockets to vent away from the open water cooled areas between the cylinders that are not solid metal. Of course, this means the 261 must have its own specialized head gasket.
After four years into production, the major quality feature was added to the 261 engine. For the first time a Chevrolet inline six cylinder came standard with a full flow oil filter system. This improvement, used only with the later 261, forced oil through a remote filter cartridge before it reached the engine. It was not like the optional by-pass oil filter system as found on 216 and 235 Chevrolet sixes. This extra helped insure longer life to this larger six cylinder that was often subjected to heavy commercial use.
A full flow oil system has been a characteristic of almost all automotive engines for over 40 years but it was just beginning in the mid 1950′s. With the 261, the disposable filter is remote and not built in as with later engines. It still resulted in a major design improvement.
As with the 235 light truck engine, the 261 came standard with solid valve lifters and an aluminum camshaft timing gear. The passenger car’s 235 was equipped with hydraulic valve lifters and a fiber timing gear for quieter operation.
During the 1955-1962 Canadian Pontiac application the lifters were the hydraulic type, the cam gear was fiber not aluminum, and it did not have the full flow oil filter. These Canadian made 261′s did not add the full flow filter in 1958 as in the U.S.
Visually the 261 looks almost identical to the 235. It perfectly replaces the smaller engine and in stock condition increases horsepower from 140 to 148.
Those planning on a major rebuild or adding performance options to their Chevrolet inline six should seriously consider locating a 261. Often there is no extra cost in purchasing a re-buildable unit, and the results will be rewarding. If you plan on adding additional carburetion, a higher lift cam, or just want additional performance and more lower end strength in your daily driver, the 261 is for you!
Locating and Identifying a 261
Though last placed in larger Chevrolet trucks almost 40 years ago, this now scarce engine can still be located and often at a price no higher than for the smaller 235. Many still remain in the original Chevrolet trucks and are now setting in salvage yards or behind farm buildings. In Canada, the big Pontiac cars are sometimes in the back rows of more isolated older wrecking yards.
Don’t overlook the wrecked and badly rusted Chevrolet cars of the 1940′s and 1950′s, particularly those showing signs of some past exterior customizing changes. The Chevrolet enthusiasts of that era knew about the 261 and its potential for added performance. Some of these will already have had extras added such as a higher lift cam shaft, extra carburetion, or dual exhausts.
When you have found what you suspect might be a 261, check a few specifies to verify you have the real thing and not the visual almost identical 235. Casting numbers, not stamped numbers, on the 261 head are very visible beside the rocker arm cover. A different set of numbers relate to the 261 block. These seven digits are located on the right side between the fuel pump and starter except for 1954 where it is located forward of the fuel pump. See chart below.
|YEAR||ENGINE SIZE||BLOCK NUMBER||HEAD NUMBER|
Watch for the “Captain’s Bars!” The 261 has two pairs of parallel raised 3/4 inch long bars cast in the block. This is not seen on a 235 except 1954. One pair is above the starter and the second pair is at the top middle of the left side of the block very close to the head. See photos below. The one exception is the early 261 produced in 1954 to mid 1955. It has only one “Captain Bar” above the starter but keeps the pair on the left side.
Most used 261 blocks are rebuildable, however often their cylinder heads will have a few very small cracks in the combustion chamber. This is typical due to occasional abuse of over heating in past years. If you choose not to add to your expense by having the cracks repaired, an alternative exists. The more common 235 head is the same except for the three pair of internal steam holes. These can be manually drilled to make the water flow just like in the 261! Sorry, but some 235 heads can be cracked even more than the 261 because they lack heat releasing steam holes.
“Warning” When Installing a 261!
The stock remote filter system has two very visible 3/4″ lines threaded into the block. One is from the pump to the filter and the other from the filter back to the block. Oil must leave and return to the engine by these lines (even if the filter is eliminated) or the engine will fail from lack of lubricant. Many 261 engines have been quickly seized after persons plugged the two oil line holes. They had many years experience on Chevrolet engines without the full flow oil system. Some thought it was an easy fix to just remove the 3/4″ lines if one was leaking and cap the holes. This procedure was acceptable on the older 216 and 235 but never on the 1958-1962 261 truck engine.
Occasionally we hear owners condemning the closed drive shaft system used in the 1/2 ton trucks prior to 1955. After questioning the negative comment, we almost always discover the real criticism is the low gearing of the ring and pinion in the differential. Yes, this lower gear ratio was created more for slower roads of year gone by, but it is by far not a poorly designed system. In fact, it is questioned if there has ever been drive shaft and u-joint combinations that exceed the durability of this GM quality engineered closed unit.
Over 50% of the surviving older 1/2 ton pickups continue to use their original closed systems. Of these, the majority have had little or no servicing other than keeping lubrications in the transmission and differential.
Consider this when you realize the last GM closed drive shaft system was produced in 1954. Many others have been in irregular service prior to the 1920′s. Also remember that many 1/2 ton pickups were often given abuse far in excess of the manufacturer’s recommendations.
What modern open drive shaft system has been able to compare with this unsurpassed record? None!! Sure, the newer open u-joints are easier to change. They better be. They require attention or replacement so much more frequently!
Another Example of GM Quality!!!
We recently received the following comment from John Berkeley Ball. He also confirms the quality of the General Motor’s 1/2 ton closed drive shaft and differential.
Dear Jim Carter
Thanks for your excellent articles. One very pertinent point I feel that you should mention about closed drive shafts is their absolute impervability to rear spring wind up. Used on the farm over soft ground with heavy loads, you could not afford to send your rear end into drive breaking pulsations every time you lost traction, whether the shocks were worn out or not (some were single action any way). What a huge advantage over the Hotchkiss rear end! this is an often unknown design attribute that Chevy engineers were unfoundedly maligned for – at least by today’s city slickers…
You may relate comments to this web site or Mr. Ball direct at firstname.lastname@example.org.
And now we’ve seen it all! A real example of American ingenuity.
Designed by an aftermarket company to keep an over tightened valve cover from leaking motor oil down the engine sides. A metal band is pushed over and around the base of the valve cover. Brass U-brackets are then secured by the two valve cover studs. This creates equal pressure around the valve cover perimeter to stop the leaks down the side of the engine.
Scott states he has seen these brackets on another 216 engine. Maybe a company in that area once offered them at local auto parts stores.
This photo was taken by Scott Golding, a resident of Western Nebraska.
E-mail email@example.com. Scott states he has seen these brackets on another 216 engine. Maybe a company in that area once offered them at local auto parts stores.
Your opinion is welcomed.
Chevrolet introduced their basic nine inch single disc clutch and corresponding diaphragm pressure plate in 1938. This pair was used in their cars and most 1/2 ton pickups with three speed transmissions through 1953. With about one million of these vehicles sold annually, one can quickly realize the high numbers of this clutch system that was at one time on the highway.
Even in 1954 with the introduction of the larger ten inch clutch disc and modified pressure plate on the new 235 six cylinder, the original design continued to sell very well as aftermarket replacements. Today, they still have a strong demand even though the majority of these over fifty year old vehicles are history. Most auto part stores now keep a pair in inventory for their walk-in customers.
To add even more validity to this clutch’s durability, GM reintroduced it in the late 1960′s. General Motors was a major producer of full size passenger buses and the demand for most having the optional air conditioning was becoming strong. Almost all new buses would now be equipped with the option. The original small nine inch clutch was combined with the newly engineered large bus AC compressor. Once again, this proven clutch was serving automotive needs!
Therefore, if you find a source for new or core clutch assemblies used from the late 1960′s to at least the mid 1970′s in GM buses, they will also fit 1938-53 cars and small trucks.
The door window is cranked up tight in the cloth channel and off you go on your daily errands. Suddenly, the glass begins to slowly lowers as you drive over side roads or contact a rough surface. In comes cold air, rain, and wind! Even the window handle turns. What’s this all about? Do you tape the window closed or wire the handle so it will not turn?
You have a window regulator spring problem! This large 2″ diameter round spring has either broken or become disconnected.
With no spring tension on the regulator, the weight of the glass creates the lowering of the support arm and window. Sorry, there is no good fix other than removing the regulator from inside the door. The picture below shows this circular Clock spring. It must be large to hold the weight of the glass panel.
Prior to the mid 1960′s, motor oil did not have the modern detergent additive. Therefore this type engine oil didn’t keep dirt particles in suspension. Foreign material would slowly settle to the bottom of the oil pan and on other flat surfaces such as the valley of the head.
If you ever removed an oil pan from a 50 year old engine that has been setting, chances are good there can be up to 1/4 inch of sludge in the bottom. This is not a bad thing! The non detergent oil has allowed the dirt to settle. As most 60 year old engines did not have an oil filter, this dirt settling was what should happen to increase the engine life.
The problem begins when a new owner wants to get his old vehicle running. He installs plugs, points, back-flushes the cooling system and changes oil. Oops, he probably adds detergent motor oil! The dirt deposits now begin to slowly go back into suspension. Unfortunately with no oil filter the dirt stays in the oil and shortens the remaining life of the engine.
Moral: Add non-detergent oil if the engine has no oil filter.
Prior to about 1962, Chevrolet trucks were equipped with round straight through mufflers. These units reduced back pressure and allowed the engine to breathe to its full potential. This caused a little extra exhaust noise in comparison to the larger more engineered oval car mufflers but trucks were for work and power.
About 1950 truck mufflers were given slightly larger inlet and outlet pipes. This allowed increased air flow which related to the slightly larger carburetor installed that year.
During the late 1960′s the Chevrolet truck Master Parts Catalog no longer listed mufflers. It appears they discontinued these units and left them to be provided by auto parts stores. By about 1995 the larger 1950′s straight through muffler was the one style available and any remaining older pipes were modified to fit 2″ inlet and 1 7/8″ outlets. Length is about 20 ½ inches.
The cars were lower to the ground and thus, required an oval muffler. This oval shape allowed it to be higher and less likely to hit an object on the road. Trucks were high and a round muffler was satisfactory.
Correct copies of these mufflers are available from Jim Carter’s Classic Truck Parts and a few other full stocking GM truck dealers.
During the 1940′s through 1950′s placing pin stripes on automobile wheels occurred on most all brands. It was an inexpensive touch that added a little flair to the appearance of a new wheel. The stripe could be added quickly with a machine on a rotating wheel. The factory didn’t need a human as on the body stripes.
GM was no exception. They had been striping most new car wheels for almost 10 years. Beginning with the 1947 Advance Design trucks, this striping even was used on ½ tons that had the deluxe package (not the standard models). This extra was continued through the 1947-1955 body style.
The attached photo shows a used original never repainted 16″ 1/2 ton deluxe wheel. Note how perfect the 3/4″ stripes are applied. With the addition of the small chrome hub cap, the wheel drew attention
The closed drive shaft ( on GM 1/2 ton, 1937-54) is supported at the front by two bushings. As these wear egg shaped over many miles, the drive shaft begins to move up and down. This ruins the grease seal and causes the u-joint to begin rubbing the “bell”. Thus noise and vibration!
Finally, with a bad seal, the differential fills with transmission grease running down the drive shaft starving the shifting gears. Then, the rear wheel seals leak, the brake shoes become oil soaked, and finally the u-joint flies apart from rubbing the bell.
Catch the developing problem early and save much expense and down time. Install what is sometimes called an “Okie Bushing”, an aftermarket, non-GM repair. This is a quick, permanent fix that does not require tearing down the differential!
Remove the u-joint bell retainer and slide this bell back, exposing the u-joint assembly. Disassemble the u-joint by removing the four bolts. The rear u-joint yolk can now be slid off the 17 drive shaft splines, exposing the grease seal in the drive shaft.
Pull out this seal and the front egg shaped bushing from the torque tube. Sometimes this bushing is difficult to remove and special pullers can be rented. Otherwise, call Jim Carter’s Truck Parts at (800) 842-1913. They have these pullers made.
Press in the long Okie bushing – seal first. Placing a wood block over the bushing end and tap into the drive shaft housing (torque tube) with a hammer. This action will then press the other original rear bushing back out of position. The new Okie bushing will now hold the drive shaft in perfect alignment, as when the vehicle was new.
They used to advertise this as a permanent half-hour fix. This is optimistic but so much easier than disassembling the differential as the Chevrolet dealers did 50 years ago.
Before the modern Positive Crankcase Ventilating System (PCV) most automotive engines breathed externally and removed their excess products of combustion into the atmosphere. It was a standard of the industry!
The lower end of the engine (below the pistons) had an attached draft tube that extended outside and below the block. It released blow-by from worn piston rings and other pollutants created from the crankshaft turning in hot motor oil.
The upper end of the overhead valve engine also must breathe. On early Chevrolet and GMC inline six cylinder engines, the venting is usually in the valve cover through factory slots. When an add-oil cap exists on this cover, it seals tight. It does no breathing.
On 1955-62 Chevrolet 235 six cylinders the valve cover slots were illuminated. It is assumed badly worn engines at high RPM leaked oil at these slots. The venting requirement was now moved to the oil cap. These redesigned caps have two features. They cover the add oil hole and vent the upper end of the engine. Their disadvantage is their internal filter can clog with oil vapors and dirt from a badly worn engine. This type venting cap must be kept clean!
The following photos show venting methods on early Chevrolet and GMC engines. Note the oil and breathing cap on the later six cylinder Chevrolet engines.
1937 through 1953 216 sealed oil cap (above)
216 valve cover vent slot (above)
1954 Chevrlot Vents (above)
1955-1962 non vented cover (above)
1955-1962 vented oil cap (above)
1963-1972… 230 and 250 with PVC system (above)
Problem: Slop in the shift pattern on 1937-47 Chevrolet 3 speed transmissions.
When shifting into 2nd gear finds your knuckles contacting the glove box door, repairs are needed
Chevrolet did not plan on these 3 speed transmissions to be in use over 50 years so repairs in this area were not often discussed by GM. You can fix it anyway!
Remove the flat plate with the shift lever from transmission by taking out the 4 retaining bolts. (Be sure to replace this plate with cloth or cardboard so no foreign object falls inside.) Take the shift tower from the flat plate top by removing four retaining bolts. The shift lever and its 2 1/4 inch tension spring can now be taken from the tower.
Inside the top of the tower is the worn brass bushing causing most of the shift lever slop. A replacement with tension spring can be obtained from Jim Carter’s Truck Parts and most of their full stocking dealers.
Sorry, exchanging the brass bushing will not solve all the problem. The long horizontal pin, through the shift lever ball, needs to be replaced. The pin will probably be worn on each end and needs replacement.
Using a drill bit is a good option for a new pin. If a 1/4 inch drill bit easily moves into the shift lever ball, move up to the next size. (Maybe as much as 9/32 inch drill bit). Use it to drill the hole oversize, then use this same drill bit as the new pin. After drilling, remove the drill portion on the bit, and you have a nice hardened pin! Note: do not cut the drill bit until you know the exact length needed. Get a correct size by turning the shift tower upside down and measuring the distance between the two notches to the tower walls.
The term artillery wheel is a nickname adapted from a scalloped type wheel often seen on US military vehicles in World War I. The similar appearance at a distance to GM’s scalloped steel wheels quickly gave them the name artillery.
On GM trucks, this style was first used during 1934-36 as a stock six bolt 1/2 ton 17 inch wheel. It was much stronger than the existing wire style wheels due to it being less susceptible to bending when hitting a large pot hole or sliding against a curb.
Though this 17 inch unit was discontinued on 1/2 tons for 1937, a redesigned 15 inch artillery began as GM’s stock wheel on that year’s 3/4 ton truck. It was stronger and wider but was still a non-split rim design. This remained the GM 3/4 ton wheel through 1945. By 1946, six bolt wheels on trucks were limited to 1/2 tons. The 3/4 ton would now have 15 inch 8 bolt split rims which remained stock into the 1960′s.
Today, we sometimes see 1947-59 GM 1/2 tons equipped with these early 15 inch artillery 3/4 ton wheels even though they were not placed on factory trucks after 1945. To many, they provide a unique appearance on the later 1/2 tons and will still hold the trucks current hub cap.
Regular 16″ Wheel (above)
1934-1936 17″ Artillery Wheel (above)
1937-1945 15″ Artillery Wheel (above)