Author Topic: Rear main seal measurements and a thanks to BARRY RABOTNICK  (Read 3219 times)

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rcodecj

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I had problems installing my rear main seal on my 390, I believe now because of size differences in the product. I want to thank Barry R for helping me solve this problem, especially the TA-31 recommendation. I have no leaks at all, I even took the flexplate off and looked. Bear with me because this is a cut and paste of emails to Barry R, and I hope it makes sense.

I measured the side seals I have gotten and this is what I got:
 
Fel-Pro
#1 set .232 wide
          .228
 
#2 set .236
          .236
 
#3 set .232
          .250
 
Yea, the #3 set is visibly wider on one of them.

I have a ROL set that measures:
.220 and
.218

My block measures :
.222 and
.223

Measure some more seals:
I picked up the new Fel-Pro side seals today and they were both .232
So measurements were ( not including the oddball .250):
 
.236
.236
.232
.228
.232
.232
.232

for an average size of .232
 
With my block/main cap seal hole measuring at .222 & .223, that's about .010 squish on the seal before you put the pin in. Doesn't sound like much, but mine are really tight.

The last one I got in using lubriplate, you could see little thin pieces of the rubber seal that were shaved off, showing through the crack of the block and the cap. To me that's too tight, and those were the .230ish ones, no way that .250 would work.

Success I believe. Remember I had a .222 hole and a .232 side seal for a squish of .010. I sanded the seal width down to .226 for a squish of.004, and they still fit in with some resistance. I used a very thin layer of TA-31 in the areas that you have suggested on the forum, and installed the side seals and main cap. I then lubed the nails lightly with TA-31 and drove them in. Towards the last it was tough, even mushing out the top of the nails lighty, so I believe I will have plenty of squish to seal the engine. If I had it to do over I would have removed even more width, as I feel the nails should not have gone in so hard.

« Last Edit: May 07, 2011, 07:56:51 PM by rcodecj »

cammerfe

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Re: Rear main seal measurements and a thanks to BARRY RABOTNICK
« Reply #1 on: May 08, 2011, 06:26:19 PM »
I've found that installing the cap while making sure that the entire side-seal areas are clean and DRY, and then  shooting a jet of 'The Right Stuff' into the hole and watching the ooze-out to be sure it's filled clear to the bottom works best for me. I've never been happy with the rubber things and Carl Holbrook ran out of his stash of rawhide far too long ago!

KS