Rear main seal installation!!
 

What do you guys do when installing 2 piece rear main seals on your BBC? Do you line up the seals mating surfaces with the main cap and block mating surface, or do you rotate the seal about 3/8"? I have done it both ways successfully and just wanted some more opinions on which way provides the most leak free seal?
Thanks Again for your responses!
Craig

i have always lined mine up flush w/ the block and no problems.....but i am no expert! lol

I've always offset mine about 3/8". If you use a sealant you can probably do it any way you want. At least BBC's have a seal, some of the **** I work on has an Archimedes screw for a rear seal.

I've done it both ways dry. Have had problems with having the halves meet at the parting line method. Never had a problem with the 3/8" offset. Directions on the seal package also say to do the 3/8" offset. Am going to do the 3/8" offset and add a dab of silicone on the two engines I am doing now.

Dave

I have always offset them slightly and used a very small dab of silicon on the cap.

Ive done it both ways. It wont leak if you say a motor head prayer when you do it. My Fel Pro seals say parting line only, IN CAPS ?? oh well.

I offset...

Watched a segment on Dream Car yesterday where they were assembling an L88 motor. When they installed the rear seal it was offset. They also put a dab of silicone seal on the mating surfaces where the seal halves meet.

Thanks for the replies. I just installed the seal and rear main cap. I offset the seal the recommended 3/8" and it went together smoothly!!:cool:

Curious Wette Vette. What did you end up with for clearance range on the rods and mains? I bought one over bearing due to the crank being somewhat undersized and now I am going to be a little tight. How did you end up fit wise and did you plastigage any at the end?

Dave

Dave,
I ended up with .002" on #1 main, .0023 on #2-#4 mains, and .0027" on #5. The rods aren't installed but we measured the clearances to be in the .0023 to .0027 range. These are probably a little on the snug side but they will work fine. :cool:
Craig

I line them up with the block and use a dab of silicone.
No leaks ever.
I probably just jinxed myself.

Craig, I think being a little tight on number one main is good. Allows full pressurization of the bearings upstream. That is about how mine will be. We will just need to make sure we warm up the oil good before running hard. I always do anyway.

PS, I bought that oil cooler from your buddy. Thanks for the lead. :)

Dave