had a 1958 272 and now a 1960 292 and both rear main seals leak like a siv. attempted to replace the 272 main seal twice and now the 292 once and the leak still exists. i tried both rope and rubber in the 272 and a rubber in the 292. any ideas?

 

Mine does too!!! And it sucks!!! I'll be checking out the responses.

 

Did you guys use the side seals with metal nails?

 

I did, yes...

 

can't remember on all three but at least two had the metal inserts. the second and third i loosened all the caps to try to get as much play as poss. before feeding the top half of the seal around wetting the seals with a little oil thinking the first may have been damaged on the way in.

 

Ok, someone who doesnt have a leaky rear main speak up. How did you do the install?

Mine hasnt fired up yet.

 

When I rebuilt my 292 three years ago I of course had the engine upside down on a stand which makes things a little easier. I guess I must have done something right because it does not leak at all- even after a hard run on the freeway between the Bay Area and Southern California. I used the neoprene felpro seal with the rubber side seals and nails.

The crank sealing surface must be smooth. If it has a groove worn in it, this must be machined or reduced using fine emery cloth. This is time consuming work done this way but it has to be done.

The seal retainer. There are two styles- and the casting marks (if I remember right) are EBU for the inferior retainer, and ECZ for the reinforced retainer. The EBU variety was used in the earlier Y's and lacked the extra ribbing used to keep it from warping The ECZ is an improvement, and will help reduce the chances of a rear pan leak too because the surface stays even, true and flat to to the block once it's tightened.

The installation. Everything must be absolutely oil free and dry. Use brake cleaner or alcohol or your favorite poison on the block and the retainer. This part is much harder to achieve on an installation in an installed previously running motor, but do your best.

I used the copper RTV on the mating surface of the retainer, and made sure the seal ends/parting surfaces were "clocked" so they did not line up exactly with the mating surface of the retainer and block. The lip of the seal was LIGHTLY lubed with STP.

I injected what I thought was a small amount of silicone into the side seal grooves, and installed the side seals, then injected a small amount of sealer into the bolt holes before tightening. I then left the engine alone for 24 hours before rotating the crankshaft.

I think that's how it went. And I realize what a pain it must be to do the job on your back, but I think the ECZ retainer, and the clocking of the seal ends is very key here.

As a side note, my failure came with the sealer I used on the shim head gaskets. It was some spray on blue stuff that did not seal well, resulting in oil leaking from the head to block seam on both sides. Very upsetting after months of weekend and night work on the motor. I ended up pulling the heads and using the tried and true copper coat. That provided a very tight seal. I think there is a picture of the engine just after I finished installing it in the truck in my gallery. It looks pretty good still....

Somebody else jump in if I forgot or mis-stated something. I forget stuff more and more lately. Like the $10 roll of the top of the line duct tape I bought two weeks ago. I hid it in the garage so my 15 year old (he likes to make wallets using the stuff!) wouldn't find it. So now I can't either!

Good luck guys...

Steve

 

Good info Steve! I hope mine doesnt leak due to not clocking the seal. Also good info on the retainer. I would be very interested in your experience using the shim gaskets. What CR your running, leaks or not, surfacing done in prep, etc. Would make a good thread to start so this one isnt hijacked.
Mike

 

And one more thing. I used a little dab of the RTV on the seal ends where they meet. Just a dab...

 

Here's a link to an article about Y seals.
Eaton Balancing