More questions of fixing a rear main oil leak

[George Miller]

I had bad luck with the Burtz seal, and the cork seal for pressure. You need a real lip seal like a chev rear main seal. But that takes a lot of rework to crank and block alum seal. Also a lot of cranks have run out on the seal area. Sum grinders do not dial in the crank. In that case it will leak any way. I always check for run out.

[spinelll]

Originally Posted by AL in NY

spinelll, I put the pressure regulator valve in the valve chamber along with the other plumbing.

.

Al
Do you have a picture of that?

[AL in NY]

spinelll, here's a couple close up photos.

[AL in NY]

george miller, could you expand on what type of rework needs to be done to the crankshaft and seal/cap areas. Right now the slicker on my counter-weighted crankshaft has been completely removed to a diameter of 2.090". Can the crankshaft still be modified to take the Chevy lip seal?

[spinelll]

Perfect pics.
Thanks Al

[George Miller]

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Originally Posted by AL in NY

george miller, could you expand on what type of rework needs to be done to the crankshaft and seal/cap areas. Right now the slicker on my counter-weighted crankshaft has been completely removed to a diameter of 2.090". Can the crankshaft still be modified to take the Chevy lip seal?

You have to build up the seal dia on the crank shaft. You have to make a piece to hold the seal in the block and rear main cap.

[DaveB]

Al and George ... I have an identical situation as spinelll and would appreciate any pics and information on how to change over to a chevy two piece seal.

[RayS]

Originally Posted by abennett

Al
I have had the same problem as you. B engine using the cork/neoprene seal, no leaks. I pulled all the bearing caps to check clearances when doing some other engine work and installed same seal since it still looked good. Installed engine, oil leaked. Pulled engine, seal was leaking where the 2 haves meet, fixed that, installed engine, oil leaked. Pulled engine, pressure checked as you did through the oil return pipe, oil was leaking around crank as the seal was not seating tight enough around crank. I then shimmed the seal for a tighter fit and pressure checked, no leak. Installed engine, after 75 miles oil was leaking BAD. Pulled engine, (getting good at pulling engine HA!) I had tightened the seal to much which then burned the seal. I have gone to the graphite rope seal from EGGE in Whittier, CA. part NO. 6382S, I am running 25 lbs. pressure and no leaks after approx. 200. I am a happy camper now. Wish you luck with yours.

Are you sure you used 1/4 tubing? I seems to be way too much. I have played around with 1/8" which seems to more in line. Do you remember if ended up flattening the tubing some?

[James Rogers]

Originally Posted by AL in NY

spinelll, here's a couple close up photos.

How is the valve train lubricated?

[RayS]

Originally Posted by abennett

Al:
The seal is listed for Pontiac and is smaller than the cavity that the seal goes in. I fabricated a filler from 1/4" copper tubing to take up the space needed to make the seal a proper fit to the crankshaft. Give EGGE a call, they may have a seal now that is better fit. It has been some time since I got mine. I wished I had taken pictures of the spacer I made, but that is hindsight now. Any more questions, I'll try to answer.
Al Bennett

Sorry about that earlier question. I was referring to this post. I have a normally oiled rear main. I tried to use a 1/4" tube to use as a shim, but it seems too big to use, so I am asking if it was really an 1/8" tube that was being used and if it was flattened or left as a tube.

[Chris in CT]

Originally Posted by Kurt in NJ

Have you checked the seal surface for runout and roughness---if the seal surface was cut on a different centerline and it moves the seal enough that it bounces it can become a pump instead of a seal ---a new seal can be compliant and tight enough at first to not leak, if the seal surface is rough it will chew some off the seal--wear it out quick.

Al, You cannot make any assumptions. Given what you have tried, you are going to have to go back and find out whether the seal surface is revolving on center with the center of the crankshaft. Testing the on-center is simple: put the crankshaft on two Vee blocks, front and rear main journals. Dial indicate the center main; that will give you crank runnout. Dial indicate the rear main seal surface, that will give you the runnout of the seal surface. Although there could be a difference of opinion here, I think that anything more than 0.0002 on a seal surface intended for a cork seal would be the cause of your problem. I'll keep my fingers crossed for you. Happy Motoring!

[Dave in MN]

Al, I am reworking an engine with the same problem you have. I studied the crankshaft, as Chris suggests, and I found the seal contact area of the crankshaft to be machined .0012" off center with the rear journal. Further complicating the issue, the contact area is machined to about the same diameter you have...near the lower limit. The engine is not pressurized. The engine will perform well on my test stand and run leak free for a couple hours and then the leak shows again. I have given up on this crankshaft and have a replacement being machined with the specific request that the seal surface be, as close as possible, concentric to the journal and right at the upper limit of diameter range. I should know mid next week if this solves the problem. FWIW: I have had the pan on and off this engine so many times; I am considering using Velcro in place of the bolts when I put it back together.

[AL in NY]

James, the valve train is lubricated three ways. First, there is a .055" hole drill in the base of the pressure relief valve to continually spray oil to the rear of the valve chamber. Second, any oil with pressure over 35 PSI is released into the valve chamber by the pressure relief valve. Since I am running the Stipe oil pump which produces in excess of 45 PSI with engine speeds over 1000 RPM's, there's plenty of oil in the valve chamber. The third source of oil is another .055" oil spray hole, but this one is directed at the rear of the camshaft timing gear (see photo). The hole sizes were arrived at by trial and error to achieve an idle oil of 20 PSI. The holes started out with 5/32"with less then 5 lbs idle oil pressure.....................now both are .055" and 25 lbs idle pressure.