VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Oakie bushing

Thanks to all who contributed advice and photos to the search feature on replacing the bushing.I replaced the bushing on my '41 Coupe with the V102 bushing from FS.Knocked the old bush out with a pin punch and installed the new oakie with a 5lb hammer using the old universal joint to drive it in.

sounds like it was easy to fit has it made a difference to the car thanks

Tony, I will need to go on the freeway to see if the vibration has improved. I still have an engine vibration when i speed up the motor in neutral.I will have to remove the flywheel and pressure plate combo for balancing but my right arm is sore from all the activity. My pressure plate has no O or X mark on it to line up with flywheel mark.Since the front bushing on the torque tube was worn and this car has had at least 2 engine overhauls and one engine swap i tackled the oakie first to stop the vibration problem.

Tony, I removed the flywheel and pressure plate for balancing. Saw the x marks on flywheel and plate after cleaning parts in the sun.They were not aligned correctly.Will let you know how it goes. Gene said that vibration could damage the bearings so i dont want to use the car until this vibration is sorted.

seems like you are on top of it I get a small vibration when I'm slowing down from 50 to 55 mph not bad goes away pretty quick so I will need to do my bearing sometime but at this stage I have bigger problems to fix as my motor cracked so I'm having to do another one up id only done 4500 miles on the last one
just missed out on a 58 235 motor as well which was a runner bugger they don't come up for sale very much over here

Tony, I got the pressure plate and flywheel back from balancing. They welded a 1"by 1/16 th disc to the pressure plate and drilled a hole in the pressure plate on the opposite side. In neutral the low and middle speed vibration has gone.When I rev up the motor it still sounds like a bucket of bolts. At cruising speed ( 50mph) the car is very smooth.The vibration has gone.Feels like another car. I still have a vibration at low speed, feels like a drive shaft vibration.I think my next move is to replace the front engine mountings.I need to remove the radiator without damaging my new honeycomb core.

Sounds like there was a balance problem in that area. If the remaining issue is only while travelling it could well be the oakie though you could try wheel swap (front to rear to front) and wheel balance (cheaper and easier.
Tony

Motor mounts are best replaced with the engine transmission out of the car, or at least all the front sheet metal (fenders, grill, radiator) removed. It can be done with the engine/transmission still installed but this will take a lot of patience and finesse. There is no way to remove the front motor mounts without lifting the engine at least an inch.

To do this you will need to remove the bolts fastening the transmission mount to the frame. next disconnect all linkage to the transmission, and remove the bolt holding each rear motor mount from the frame. The front grill will also need to be removed to access the front mounts. At this point you can decide to remove the radiator. It may be possible to leave it in? Any work I do on the radiator or near it I protect the radiator honeycomb core with a piece of cardboard. It also doesn't hurt to remove the fan blades on the water pump to improve access.

You will need an engine hoist or a floor jack to raise the engine. If you use a floor jack you will need to build a frame out of wood/metal that you can use to jack up the engine. The wood needs to rest on the oil pan where it is bolted to the engine block. Your design of the lift must take into concern your needing to place your fingers safely between the engine block and frame. The oil pan is not strong enough to hold the weight of the engine.

Good luck, Mike

P.S. Do you have any idea the age of your motor mounts? It is common to have them deteriorate through oil leakage and driving conditions. After 20 years one could assume they need replacing.





Each front mount has two bolts holding it. One bolt is on the bottom of the frame cross member. Here is a link to what the mount looks like Front Motor Mount.



Rear motor mount.

I agree with Mike's approach. I replaced all 3 sets of mounts in my '37 Master Coupe with the engine and transmission in the car. I did have the radiator removed but did not remove the front sheet metal. Just take your time and think about how you are supporting things as well as what wrenches and sockets are needed to access the hardware. Also check the bolts that hold the transmission to the flywheel housing and the those that hold the flywheel housing to the block.

I strongly agree with Mike's assessment that if the mounts are 20 years old they all need to be replaced. Due to oil, heat, and time they deteriorate significantly.

Replace the front mounts and the transmission mount before replacing the side mounts. As Gene has often reminded us the side mounts are not intended to support much if any weight. Their purpose is to control the torque reaction of the engine. In the shop manual there are instructions about how to set the clearance for the side mounts.

Admittedly nitpicking here.

The parts book calls the mounts at the bell housing, "Cushions."

There are two types for 1935-48.

The "W" or "m" thpe for all passenger model, except Cabriolets. Part numbers 756056 fort the left side and 756057 for the right.

The retangular type for the Cabriolets. Part number 377928.

The "W" type is threaded so that they fit only left or right. The after-market ones had two extra threaded holes so that they would fit either side.

I don't want to see no stinkin 377928s on anything but 1935-48 cabriolets.

You're welcome.

Charlie

BTW: Most of you already know the above information. I know that Gene does.

he retangular mounts were used on ALL 1935-1946 cars. That was the only choice. In 1947 the new Z mount was used on every thing except convertibles. The GM ones came is left and right due to bolt hole location. Gyps had double holes and fit both side. This mount was also specified for REPLACEMENT on previos models but are correct (for judging) on 1947-1948 models (except cab.) only.

The Z mount is softer and was designed to eleminate torque vibration at low soeeds. In other words you could accelerate from 10 MPH in high gear with no (or less) vibration.

I had Z mounts in my '39 for years and judges never noticed.

I'm pretty sure that the option of replacing a rectangular rear engine mount with a Z mount requires a different engine bracket? I ordered a set for my 41, from Chevs of the 40's, and either the frame design was a compatibility problem or my engine bracket did not accommodate the Z design?

Good luck, Mike

P.S. The Z/M Motor mount requires the use of 48 engine brackets. The rectangular shaped mount fits all 35-47 cars and the 48 Cabriolet according to the Chevs of the 40"s catalog.

I have read that also but never had a problem switching from one to to the other.

The information I quoted above was from my 1929-1950 Chevrolet Parts book. Nothing more.

Owing to the fact that I was not present at each and every installation of the chusions from 1935 thru 1948, I have no clue as to what was actually installed at the factory. Could have been a block of wood as far as I know.

Charlie

This is a comment about the side mounts and their capability to hold weight. If you remove the transmission, those mounts hold the weight of the engine at the rear. The shop manual for my 38 does not talk about adding extra support for the engine when removing the transmission.

Sorry for any confusion I might have created.

I agree that the side mounts will support the static weight of the engine just sitting in the chassis.

My comments were based the instructions on page 170 of the 1941 shop manual. I followed a similar process when I replaced the mounts in my '37 Master Coupe.

These steps ensure that the side mounts are properly positioned to control engine movement without being overloaded while operating. If the clearance is too great the engine will move more than it should. If it is too small the extra weight will shorten the life of the side mounts as well as more vibration will be transmitted to the frame.

I don't understand why the retangular cushions continued to be used on the cabriolets after the Z type came out.

Chevrolet must have had a bundle of them left over. Could it have been that the cabriolet frame was more rigid and thus didn't need the cushions as much as did the chassis without the "X" box.

Charlie.

It was a space problem due to the X type frame used in a cabroilet.

What then was the space that was invaded by the use of the "Z?" Seems to me thare is plenty of space where the cushion goes.

Of course, I accept your explanation, Gene, but I'm not convinced.

Charlie

Thanks Mike for your photos and all the advice