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

ok, looks like I sprung a leak from the rear of the oil pan.



I dropped the pan to get to the rear main seal, but could it just be that the oil pan gasket is old and dried. I don't know how long the engine sat before I bought it.



Should I just go ahead and drop the rear main cap and cut the grove in the bearing since I already got the pan down?

With te good impression the pan left in the cork I doubt if it is the gasket/cork.

Looks like the last person that put the pan on new what they were doing. As Gene mentions good impression on the cork. It even looks like it was tightened right because the gasket is not distorted around the bolt holes.

What year is the engine?

The engine is a 1938 Chevy 216.

If the cork appears to be in good condition, do you have any other suggestions why it would be leaking?

Ha Guys,

I thought we already discussed that a 1938 216 doesn't have a rear seal, and that the solution for a leak in the area is to cut a small groove in the rear main bearing?

Modoil, please check out the link in my above post 1948 rear main seal. There is a picture of the rear main bearing and where to cut the groove.

Gene stated above that, "If the bearing is too looose to much oil can pass by and the system can't handle the volumn.....that plus some other things can cause a leak."

Hopefully, Gene will jump in and tell us what are the "other things."

Good morning,
Mike

The clearance for the rear main bearings could be on the loose side and in need of shimming.

OK, so that is why I asked that question. I haven't had my 38 engine apart yet but I understand there is a check ball in there that stops the oil from running out when the car is parked on a severe grade. If that ball gets stuck, it will cause a leak.

I have never seen a "stuck" check ball....not says it couldn't happen.
If it were mine I would adjust the bearing (by removing shims).
Cut the grove, and install the pan gasket in the correct sequence (sides first, end corks last) and say a prayer.

If the pan gaskets are good, is it possible that the oil is coming from around the cam seal?

While anything is possible that is highly unlikely.

I have seen lots of them! On the 1929-32 engines for example, it is fairly common for the check ball to be stuck in the up position allowing the return oil to run onto the ground instead of into the oil pan. Many dudes remove the check ball to eliminate the problem.

I agree it happens on the older models.

Chevgene, I ask, with tongue in cheek, what do you say if you are an atheist? And JYD, how about the Dudettes? Remember, we live in an age of -------- and other bulls***. Beamer

I had thought of that and they would just have to forgive me.

In the photo above, the motor is not running as seen by the flywheel but there appears to be oil pouring out. If that is so, wouldn't that be caused by more than just oil leaking from the bearing under pressure?

The engine is running. I think it was just luck how the camera made it look like it's standing still.

My concern is is, if I cut the the grove in he bearing, won't that scratch the crank shaft jurnol? Do I use the same shims that are currently under the bearing cap? And what do I torque the cap bolts to?

Wow, you must have a fast shutter function going on your camera. So that is quite a flowing leak that you have. Did this come on all of the sudden?

I wonder if the rear cam plug could have popped out? Looking again at the picture knowing it was running you have a sizable leak going on.

I don't see the oil running out....what am I missing?
see a drop hanging on the end cork which is normal.

In the first photo, there appears to be a stream of oil falling fom the rear edge of the crossmember. It is yellow and contrasts against the black pipe.

I hope this link works. It is a bad leak. The car is some what new to me. I assume it was an older restore that has been siting around for years. I knew it leaked some, but not this bad. I had just changed the oil, 10-30 weight. Maybe it was thinner oil than what was in there originally.

That works...looks like more tha just the rear main.
Perhaps some one put a timing gear in with out removing the camshaft and knocked out the freeze plug behind the cam.

Before you go any farther drop the rear main bearing cap for inspection.

I just went out and looked at my 38. The transmission cover is off and there is good access to the housing inspection panel. However, I don't know if the cam plug in the block is visable from there.