Going to be replacing the rear main seal on my 1970 350. Using the TA 2 piece neoprene seal. TA says these are a direct fit, need no trimming. If my mechanic follows Jim Wiese's write up for the 455 will he need to trim the seal? TIA
No, the 350 neoprene seal is a direct fit.. One should always check fits with a two piece rear seal.. place the seal on the seal surface of the crank, with the crank out and on the bench.. there should be a .020 to .030 gap when you fit the seal together with light pressure.. the gap should be on on one side, with the other side being butted together... this is your seal preload. Then you should be able to push the seal together, to butt both ends, relatively easily... if you have that, your good to go. Then the seal should be installed in the engine, as a dry fit, with the crank out. Put the seal in the groove, top and bottom. Offset it so you can see the one end. Torque that rear cap up to spec, and visually inspect that the seal ends are butted up to each other, and the seal is not bowing or distorting in the groove. I don't do a ton of 350's, but I don't recall having a problem with TA's 350 rear seal. A very small film of sealer behind the seal is still a good idea. JW
I usually put a little dot of sealer on the ends also. Does it do any good???? Just makes me feel better. Tom T.
I put the ford 460? one piece in mine never leaks a drop no modifications needed found that you can use them on here somewhere so I tried it cause I don't like leaking rope seals
The 429/460 use a 3" main.. I use 460 rear seals in Tomahawks.. Be aware of the fact that rear seals for the 455 are a moving target on these things.. Several of the Ford and Caddy rear seals no longer exist, in the form they once where. Molds wear out, and then they are replaced, and that new product is often not the same.. even with the same part number. The new Fel Pro 200 6cyl Ford seal is a good example.. TA sold that seal for decades, and we all used it, with varying success over the years.. If you turned the crank down to the 200 size, they worked better, and did not melt out.. Then Fel Pro up and changed the seal, without telling anyone.. all of the sudden my rear seal failure rate went from about 2% to about 50%... in the span of 6 months.. and the worst thing is that the failure I had, on a perfectly turned crank seal surface, would not show up until after the engine was in the customer's car.. No problem on the test stand and on the dyno... Upon disassembly, I found that they must have changed the material, as the seal lip was disintigrating.. not so much melting, but flaking apart.. TA now has a new 2 piece seal, I have not tried it yet.. But it is made for TA, it has his name on it.. I assume it is the correct diameter for the Buick crank seal surface. It is the good viton material, I saw one at the Nats.. I have had 100% success so far with 1 piece seal from BOP.. Sure, it's expensive, but if you stand behind your product, it's a hell of a lot cheaper than replacing a rear seal down the road.. for you home builders, not much sucks worst than having to replace the rear seal on a brand new motor. The BOP one piece seal is a dual lip seal, and very forgiving on variations in seal groove diameter. it is a Trim to fit deal. That is not hard to do.. I am still technically in my proving phase on that seal, about 3 more builds and another 6 months, and I will officially recommend it.. And will do a write up on it's install.
