Distributor Seal Is Leaking, Help...

[terd ferguson]

I posted this on the hamb, but no suggestions have worked yet. Here's the deal. I swapped intake manifolds and valve covers. I had old factory ('80) valve covers and a newer Edelbrock Torker. These came off in favor of finned Corvette valve covers and an older Edelbrock Torker intake manifold. I drilled the manifold for a PCV valve.

When I put it back together, I used the old distributor seal. It leaked. I got a new seal and used some silicone, I think I ran it before it fully set. It leaked again. I got a new gasket and cleaned everything with brake cleaner and installed the new gasket dry. It still leaked. I had the suggestion of using two gaskets, so I tried that using gasket adhesive to hold the two together. It still leaked. That's where I am now.

Here's what I know. It didn't leak before the swap. It is not leaking at the valve covers. It is not leaking at the oil pressure sending unit. It is not leaking at the pcv valve or grommet at the back of the intake manifold. I am nearly positive it's not leaking at the rear of the intake manifold (RTV was used for the ends). The distributor is factory HEI from 1980. The mounting surfaces of the intake and dizzy seem fine.

Here's what I plan to do tomorrow. I got a new hold down bracket and another gasket. I'm going to see if that makes a difference. I thought maybe the hold down bolt hole was a teeny bit further away not allowing the hold down to put enough pressure on the dizzy to stop a leak. I also plan to check the distributor seating with no gasket to make sure it is fully seating.

Beyond that, I'm at a loss. The only other thing I know to do is to remove and reinstall the intake just in case the end seal didn't seal. I just don't think that's it because I don't really see oil being blown out the back and up then forward to around the distributor mounting hole. The leak is what I'd call pretty heavy. It will have a saucer sized drip on the pavement in a short time and after a short drive.

So help me out please. I'm almost at wits end. I'm open to any suggestion. If you suggest RTV on the gasket, tell me how I can set the timing without ruining the RTV seal. Anything else? Let's hear it.

And thanks in "advance" for the help. I hope this question isn't "retarded".

[Big Fenders]

Never heard of a distributor seal leaking before. Have you checked out where the oil sender screws into the block...just about same area.
Bob

[Eagar1]

It may be possible that your rear main seal is leaking.
the distributor slides down into the top of the oil pump which is bolted to the rear main cap. The old rope seals are very good if they arent touched, but once you disturb them, they can leak. When you put your distributor back in, it is possible that youdisturbed the rear main cap, and that is what is causing your leak. I know it sounds odd, but its the only thing you didnt check.

[protrash64]

The dizzy must not be seated for some reason. I would pull it and check the hite against the engine/manifold combo. It doesnt have an adjustable collar does it?

I would check that sending unit again, also.

[terd ferguson]

Originally Posted by Big Fenders

Never heard of a distributor seal leaking before. Have you checked out where the oil sender screws into the block...just about same area.
Bob

I checked this. It's tight and not leaking here.

Originally Posted by Eager1

It may be possible that your rear main seal is leaking.
the distributor slides down into the top of the oil pump which is bolted to the rear main cap. The old rope seals are very good if they arent touched, but once you disturb them, they can leak. When you put your distributor back in, it is possible that youdisturbed the rear main cap, and that is what is causing your leak. I know it sounds odd, but its the only thing you didnt check.

I don't think it's the rear main. The oil is around the distributor mounting hole. Oil would have to blow up and forward to get up there from the rear main. I'm not saying it's not possible though.

Originally Posted by protrash64

The dizzy must not be seated for some reason. I would pull it and check the hite against the engine/manifold combo. It doesnt have an adjustable collar does it?

I would check that sending unit again, also.

I'll check the hieght with no gasket tomorrow. There's no adjustable collar. The oil pressure sending unit is good.

[chevyguys]

Had this problem along time ago on a motor that was building up to much crankcase pressure. My PCV was not working correctly and the motor would wistle through the distributer gasket. Oil was also seaping out the distributer gasket. I was using the old style corvette covers with no breathers.

Are you sure your PCV system is working correctly?

[terd ferguson]

Originally Posted by chevyguys

Had this problem along time ago on a motor that was building up to much crankcase pressure. My PCV was not working correctly and the motor would wistle through the distributer gasket. Oil was also seaping out the distributer gasket. I was using the old style corvette covers with no breathers.

Are you sure your PCV system is working correctly?

This sounds plausible. I have a brand new breather cap on the filler tube. Maybe a new pcv valve wouldn't be a terrible idea either. They're only a couple of bucks.

[terd ferguson]

How tight should the hold down bolt be?

[70k52wd]

What did you do to fix the dist leak? What was the cause of the leak?
Glad you got it fixed.

[terd ferguson]

Originally Posted by 70k52wd

What did you do to fix the dist leak? What was the cause of the leak?
Glad you got it fixed.

I tightened the hold down bolt properly and got a new hold down (cheap and just in case). I had been way over tightening the bolt before. The leak is much smaller now and no more oil is pooling on the intake around the dizzy. No more oil is leaking at idle either, only on the throttle. I can kind of see where it's coming from with a mirror, I just can't tell if it's the sending unit or the intake seal just below it. I figured I'd do the sending unit first as it's easier and since it's plastic line is so fragile it would've been easy to break without noticing.