Oil leak

[37 truck]

Completely rebuilt 1940 flathead, bored 20 thousand over a 239 cubic inch. Egge four ring pistons, Max 1 cam, Edelbrock slingshot with two 97's. Engine runs really strong and sounds fantastic. Has about 50 break in miles, and has started leaking oil out of the hole in the flywheel pan. I figured oil could only come from the slinger, the oil pump to cam cover, or the plug from the oil line in the block, so eliminated the oil pump to cam cover and the plug by putting a shop vac to the road draft tube, which stopped the oil flow immediately. My Dilemma is how to stop this leak without pulling the engine and changing over to a newer type rope seal. Vacuum pump, or PCV? Could it be blow by from the rings not fully seated yet?

[petehoovie]

Originally Posted by 37 truck

Completely rebuilt 1940 flathead, bored 20 thousand over a 239 cubic inch. Egge four ring pistons, Max 1 cam, Edelbrock slingshot with two 97's. Engine runs really strong and sounds fantastic. Has about 50 break in miles, and has started leaking oil out of the hole in the flywheel pan. I figured oil could only come from the slinger, the oil pump to cam cover, or the plug from the oil line in the block, so eliminated the oil pump to cam cover and the plug by putting a shop vac to the road draft tube, which stopped the oil flow immediately. My Dilemma is how to stop this leak without pulling the engine and changing over to a newer type rope seal. Vacuum pump, or PCV? Could it be blow by from the rings not fully seated yet?

[37 truck]

Thanks Pete, much nicer to see, hope some has some ideas.

[Bored&Stroked]

I believe in order to change to the newer type seal, the crankshaft has to be replaced any/or modified? I'm thinking that the 'slinger' cannot be used with a rope type seal? I believe it can be ground off . . . but obviously that is taking the whole engine apart. I don't know of an easy solution . . . but I also am not sure exactly what is causing the issue?

What oil pump is in the engine - how much PSI?

[cadillac512]

Silly question, but does it only leak when running? I ask because the pan's pretty ugly and might have a crack at the divider wall at the bottom rear.

[alanwoodieman]

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what about the rear cover for oil pump/cam gear or the plug not sealed--way more oil than a leaky rear rope seal. take the starter off, push start the car and get an inspection camera into the starter hole and look for the leak. we actually did this on a fresh merc rebuild only to discover the rear main had been ground with a taper that allowed the oil to flow

[37 truck]

The oil only runs when the engine is running. I don't think the cover over the oil pump to cam gear is a contributor sense the flow stops when I add a vacuum to the road draft tube. If that was the source of the oil it would not be affected by vacuum. I will check on the oil pump that was installed and let you know. Pressure reads about 30 at idle and goes to 50 at higher rpm.

[37 truck]

The oil pump is a standard flathead pump from Melling, purchased at Speedway.

[Kube]

For that much oil to be getting there, methinks the cork gasket between the
"bell housing" and the oil pan proper has been installed incorrectly.

[alanwoodieman]

Cube--only leaks there when the car is moving and the oil runs up rear of pan-you can ask me how I know about this!

[Bored&Stroked]

Your issue may be the Speedway pump . . . which is most likely a clone of the 49-53 pump. Due to its helical teeth, it puts out more volume than the original pump and maybe the volume is overcoming the ability of the stock slinger system to handle the oil that naturally comes out the backside of the rear main. Did your rear main cap have the little "pipe" installed that helps oil drain from the slinger?

[Kurt in NJ]

How full is the oil, try lowering it to just above add

[Kube]

Originally Posted by alanwoodieman

Cube--only leaks there when the car is moving and the oil runs up rear of pan-you can ask me how I know about this!

Am I looking at this incorrectly? It appears to me the oil is coming out of the hole in the pan where the cotter pin should be. Yes?

[37 truck]

Kube, the oil is coming out of the hole in the in the flywheel cover. Where the cotter pin would be. I do have the pipe coming out of the rear main cap, although I have read that Ford stopped installing those at some point. I have made a diaper of sorts to allow driving it on a limited basis. I will put a few miles on it and see what happens. Can't hurt at this point.

[Kube]

Originally Posted by 37 truck

Kube, the oil is coming out of the hole in the in the flywheel cover. Where the cotter pin would be. I do have the pipe coming out of the rear main cap, although I have read that Ford stopped installing those at some point. I have made a diaper of sorts to allow driving it on a limited basis. I will put a few miles on it and see what happens. Can't hurt at this point.

It'll be interesting to find out the cause. Probably not so much fun to repair. My money remains on that pesky gasket I'd mentioned in a previous post.

High volume pump? I suppose that could be the cause but given the fact a zillion have been installed without this issue leads me elsewhere.

Just a thought... are you 100% certain the plugs were installed at the rear of the block???
I have repaired freshly rebuilt engines for clients wherein the rebuilder did not install these.
However, those engines were not drivable as the oil was coming out way too quickly. So, I'm back to that cork seal...

[Bored&Stroked]

Yeah - in my mind you'll need to pull the pan and maybe see if that cork seal is an issue - that would be by far the easiest fix. If it is related to the crank and main bearings . . . things get a lot more complex and expensive.

[Kube]

Originally Posted by Bored&Stroked

Yeah - in my mind you'll need to pull the pan and maybe see if that cork seal is an issue - that would be by far the easiest fix. If it is related to the crank and main bearings . . . things get a lot more complex and expensive.

I agree that the pan should come off sooner rather than later. This bad of a leak and the clutch will soon become contaminated and need replacing as well.

[37 truck]

Third generation shows they have rebuilt original style oil pumps, I could drop the pan, check the cork seal at the back for a cause, replace the pump and install all new gaskets. That is about as far as I can go with this with the engine still installed.

[Bored&Stroked]

Originally Posted by 37 truck

Third generation shows they have rebuilt original style oil pumps, I could drop the pan, check the cork seal at the back for a cause, replace the pump and install all new gaskets. That is about as far as I can go with this with the engine still installed.

That sounds like a good "next steps" plan to me. If that doesn't work out, then you'll have to pull the engine and get into it deeper.

[37 truck]

Would you keep the pipe on the rear main cap, or delete it? The flywheel is the deep dished type so the pressure plate and disc are inside a little bit, maybe some protection from oil.