1 Peice rear main seal

ou812545 · #1 (**permalink**) 03-09-2009, 10:14 PM

I recently had my 418w rebuilt. It's a 1971 block with the 1 piece seal.
The problem we ran into is the block was aligned bored a few times in it's life and the 1 piece seal did not want to stay in place. Due to the machine work, the location of the seal is no longer a perfect circle. The seal would actually work it's way out overnight as the engines sat on the engine stand. We tried some permanent cement and it seemed to work, Until!
We installed the engine over the weekend and after the first 100 miles, the seal is now leaking. We suspect it's coming from the out diameter. Between the seal and the block and bearing cap. No the seal and crank. We used the rigged steal stamped Fel-Pro rear main seal.

My question is?
Is there a rear main seal you recommend other than the Fel-Pro that may work better when the block has been align-bored a few times?

I can't be the first person to run across this problem.. Any suggestions?

Thanks,
Dan

Rick Parker · #2 (**permalink**) 03-09-2009, 10:48 PM

To late to do at this point but clocking up on the main bearing bore and remachining the seal bore in the Block/cap should have been done. There is probably too much crush on it now and the seal wants to squirt out of its register bore.

ou812545 · #3 (**permalink**) 03-10-2009, 07:41 AM

Rick,

That is exactly what is happening. Any ideas or different options on the rear main seal?

Dan

Jerry Clayton · #4 (**permalink**) 03-10-2009, 07:47 AM

You can measure across the seal hole top to bottom and side to side

Take the side to side as blue print specs( unless you have the specs)
Set up the main cap in a mill and with a boring tool set to bp specs, take a moon shaped cut which will move the hole back to a assembled round properly sized hole

vector1 · #5 (**permalink**) 03-10-2009, 02:12 PM

drill and tap for screws to hold the seal in, 3 or 4 should do it.

i've seen an illustration somewhere but can't find it.

Rick Parker · #6 (**permalink**) 03-10-2009, 02:39 PM

Dan, I spoke with an engine machinist, here was his suggestion to be done without removeing the engine or tearing it apart. Other fixes are a better resolution but necessitate striping the engine and remachining the seal register diameter:

With a new unused seal. Using a belt sander, carefully sand the outer diameter to remove the outer layer of rubber coating. Clean the seal carefully. Using a product such as "Hondabond" (used by Honda in lieu of gaskets, (available at their parts departments) coat the outer diameter of the seal (do not use a silicone). Clean and dry the area where the seal is to be installed so it is free of any oil and dry. Berrymans Chemtool comes to mind here. Install the seal and then apply the same adhesive (Hondabond) around the outside of the seal face to complete the retention of the seal and effect a complete barrier for oil seepage. You should end up with a clean seal face and a neat "Ring" of the adhesive that is visable around the outside diameter. When cured this should hold the seal in place.