VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Engine Rear Seal

Its behind the fly wheel housing.

Finally found some time to work on the 38 Chevy again.

I pulled down the pan and the rear main bearing cap. I know the 37-39 Chevys don't have rear main seals, but what is the rope, cloth, seal thing that it does have?



What is this seal called? And where do I get a replacement?



How do I replace the part that is still in the engine block?

After I replace the seal, where do I cut the groove in the bearing?



Is there a check ball in the bottom of the bearing?

It appears that somebody put a seal in there which is not supposed to be there. I believe that groove is there to drain the oil coming off the bearing. That seal is blocking the drainage. Also, although I haven't seen it on mine yet, you appear to have a photo of the check ball arrangement.

Yes, that "seal" is not supposed to be there. You have to get that junk out of there and make sure the check ball is clean and free, then adjust the bearing clearance. Like old216 said, that seal is blocking the drain and forcing the oil out past the bearing.

I've never had a my 38 216 bottom end opened up. The picture appears to show a rope seal put in a groove for the oil slinger washer that appears to be showing in the groove towards the fly wheel. It looks like the oil slinger has shreaded the rope gasket. Is this what I'm seeing in the photos?

So that is what the oil slinger looks like on a '38.

I think the FelPro gasket kits come with the rear bearing rope seals for all 216's, so maybe the previous mechanic assumed it was required, as I also assumed when I looked in the manuals.

Another good reason to find someone who really knows the Chevy 216 and its history before having the engine rebuilt or repaired.

I've only seen the slinger out of the engine and it looks like a thick washer with slanted radial slots that I believe are designed to catch the oil oil as it leaks by the rear main bearing and then sling it back into the drain passage to the pan. Is that right Gene?

If I cut a groove in the bearing, should I cut it from both oil passages? or just the first one?

Make the grove just in the front surface of the bearing about 1" from bottom center. That is to the front of the large oil passage.
Make sure the check ball is free and get all the old seal debris out of the return oil passage.

I would not put a large groove in the bearing, more like a deep scratch than a cut. The larger you cut the more oil can flow reducing oil pressure.
Tony

would estimate about .020" is enough.
The 216 gasket set comes with several gaskets that are NOT used on all 216 engines.

I removed the seal from the bearing cap, and above the crankshaft. I cleaned out the return hole and made sure the check ball moved freely. I don't know if I needed to, but I went ahead and cut a groove in the bearing. I cut it about the thickness of two hacksaw blades. After putting it back together, I filled it with some 10/40 oil and let it run for a little bit. The oil pressure stayed high, and that nasty leak is gone.

I don't know how I would have figured this out without the help of the members of this website. Thank you everyone.

Great, glad to hear that you were successful at stopping the oil leak!

They usually leak worse when cold due to higher oil pressure and slower return of the oil.

Great to hear your repair went well. Thanks for posting the good pictures of the rear main. It really helps to see what is being discussed. Some on us aren't familiar enough with all the innards of the mechanicals to follow along without being able to see the assemblies in pictures. I hope your 216 keeps turning for years to come without needing to open the bottom up again.

Gene,

Would the same size and location cut groove be helpful on a 31 194?

Thanks

Dave

While the rear main on a 1931 is fed by gravity I thing a grove would help. If it were mine I would limit the width to one hack saw blade rather than two.

Thanks

Mark,

I'll try to answer your question from a non-machinist point of view, so my terminology might not be correct.

Prior to the machining process for the one-piece seal the block is set-up with shims set to correct specs for all bearings with the crank in place. Then the crank is removed and shims put back in place. During the machining process, I think the term is "line bore", the block is set up for a line bore but only the rear main seal is machined to accept the one-piece seal while maintaning the specs needed on all bearings.

Sorry if this doesn't make any sense but this is what I witnessed during the machining process for my one-piece seal and my seal is doesn't leak at all.

Fleetboy,

Thanks for the response. I understand the process for boring the rear seal cavity, as you described it. What happens after 30,000 miles or so when you need to remove a couple shims from the rear main bearing to account for wear? When you reinstall the bearing cap,the seal bore will be slightly oval shaped, which would squeeze the one piece seal into a corresponding oval shape. Perhaps the small amount of ovality would not be significant enough to cause leakage at the seal.

Did you use a Timken 3893V seal? Did you have to polish the OD of the flange that the seal rides on?

Mark