Oil in Distributor

This is the second distributor to do this to me. I have oil all over the underside of my hood, the rear of the engine, firewall, and puddled at the back of my intake. I pull the cap off the distributor and there is a lake of oil in there.

I'm running a (SBC 355) Performer intake, and a Summit HEI distributor. Also have an ASCD Ram Air hood (SS style), and a Melling high volume oil pump cycling 20W-50 synthetic.

My theory: High oil pressure forces its way up the distributor shaft (blowing seals?) and floods the distributor. It leaks down onto the intake and when the car is at speed, the air rushing over the intake via the scoop in the hood is spraying the puddled oil onto the previously mentioned surfaces.

I've double- and triple- checked for additional leaks, and the only other possible leak locations would be where the distributor meets the intake (can't tell if it's really leaking because of the oil dripping down from inside the cap). Yes there is a gasket there and it's about 4 months old.

When the engine is cold (lately, morning oil temps are approx 60*F) I'll see about 70 psi around 2500 rpm. By the time I get to work my oil psi is around 55 at same rpm.

Does this oil intrusion of my distributor indicate a serious problem inside the engine? If not and assuming the source of the problem is the distributor itself I'm sure oil coming up into the distributor isn't desired, so it has to be defective now(?). Can anyone recommend a stout distributor that can handle higher oil pressures?

Thanks for your time.

If you are truly seeing oil inside the distributor, it would be due to bad distributor shaft seals. I'd try an MSD distributor for your application (HEI, Late model, etc they should have something that will work for you). They are stout and I've never seen one leak.

One more place to check for leaks (if the oil is not inside the distributor) is the rear of the intake manifold. This is a common place to have a leak. It either doesn't get enough RTV, or if you use the rubber gasket and it moves, or you try to use RTV with the rubber "end gasket" that the intake gasket set sends, you will usually have a leak. Not saying this is what you did, just thought I'd mention that it is a common place for trouble.

Good luck!

High volume pump? 20w-50? Your problem is that the oil can't get through the bearings fast enough....it has to go somewhere so it blew the shaft seals in the distrib. You'll have to do something about the seals (either replace them or change the whole distributor) but if you keep running 20w-50 you'll have the same problem again.

The engine is a crate engine built with nitrous oxide in mind. I assume the ring clearances were backed off a bit for that, I say this because at about 2000-2500 miles into an oil change I start burning oil and notice the oil is diluted by fuel (I switched to synthetic and no longer have that problem).

20w-50 was the recommended grade (by the engine builder) to use in the engine, maybe for that reason as well.

Originally posted by TheGreatJ
High volume pump? 20w-50? Your problem is that the oil can't get through the bearings fast enough....it has to go somewhere so it blew the shaft seals in the distrib. You'll have to do something about the seals (either replace them or change the whole distributor) but if you keep running 20w-50 you'll have the same problem again.

I ran 20W-50 for a long time in mine with no problems. I don't think that is the cause of the leak. Now, a distributor with "junk seals" in it may not like that oil weight, bolume and pressure, but I can't see placing the blame on the oil.

My thoughts