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2 piece rear main seal
#1
1982 Ford Mustang GT 5.0L
Mild performance rebuild including align bored block replaced factory rope type rear main seal with new split lip 2 piece Felpro seal.  Removed the factory pin for rope seal of course and filled with RTV sealant.  Have done this on several rebuilds with good results but this engine leaks badly at the rear main.  Suspect when the machine shop decked the main caps and align bored the block's main journals the sealing area of the rear main cap is now elliptical or out of round and the new split lip cannot seal.  Looking for solution.  Would switching back to a rope type rear main seal be the best course?
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#2
Hi,

Align boring should have created a round RMB seal area.

When the new RMB seal was installed, did the ends of the RMB seal stick up just slightly past the RMB cap & block? Say around 0.010” to 0.020”. This creates the crush necessary to keep the seal in place and from spinning. Not enough or too much can create a problem.

Look over the old seal at removal to help determine what went wrong.

Going back to a rope seal is possible but it is more of a "controlled leak" as there will be some seepage/leakage with a rope seal.

We would recommend staying with a rubber seal if you can determine what caused the first one to leak and correct it. Check the rear main cap with a bore gauge to verify roundness of the sealing area.
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#3
I have a ford 460 with a 2 piece rear main. I guess I may have received the wrong part. The seal sticks out of the journal about a half inch in each side. there should be some sticking out about maybe a fingernail thickness.
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#4
(05-29-2017, 08:58 PM)Guest Wrote: I have a ford 460 with a 2 piece rear main. I guess I may have received the wrong part. The seal sticks out of the journal about a half inch in each side. there should be some sticking out about maybe a fingernail thickness.

Hi,

What is the part number of the seal you installed?
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