So I tried the BOP one-piece viton rear main seal. Everything went well until I tried to install it. It is very difficult, at least for me (I'm almost 60 but have been turning wrenches since high school). You have to drop the crank in and try to fit the seal in the groove at the same time. I first tried it by myself, and ended up with the seal bent. Straightening out and getting a helper, I tried again to no avail. The problem is keeping the lower ends butted together tight enough while pushing the seal in the groove while not allowing the weight of the crank to spread apart the ends. Then if you get it close enough, you have to support the crank while putting the cap on so that the weight doesn't push the seal against the groove so that the cap can push the seal in and re-butt the ends. It did not work for me so I ended up with the JV600 trim-to-fit 472 Caddy seal.
Yeah, that seal is a real **** show just like their two piece and if you go on their website, it says we started with a clean sheet of paper and designed it specifically for the Buick and Pontiac which is totally not true for the Buick seal.You have to trim at least a 1/8 inch off each end. The Caddy seal seems to be the best fit closest to the Buick dimensions of crank. Undeniably the quality of the material of the seal is the best, however, any time you have to remove that much material off of a circle it is no longer a circle. The Ford seal works if you have the crank turned down to the Ford diameter however, Fel-Pro went and changed their material which is junk so I use that seal with the earlier material if you can find them, that seems to work the best for me anyhow
I've always had good luck with the 2 piece bop enterprises seal. It has a wider contact area and I've never had to trim it.
I have used the BOP 2 piece seal in an earlier build and it did great, no leaks at all. And I thought the one piece would be an improvement. I trimmed the one-piece and got it the way it needed to be but went downhill after trying to put the crank in
Previous owner of my LeMans used the BOP 1 piece in a '73 400 Pontiac that I'm driving now. Leaks. Motor is coming out so I can replace it with BOP rope seal which has always worked well for me.
Thanks for posting this Scott. You have saved me some time, money, and aggravation. I preparing to assemble a short block and I was considering one of the BOP one-piece seals but now I think I'll just stick with the seals I have used before with relative success (the BOP 2-piece seal and the old-school Caddy seal).
I’ve used TA s seal on the last 4 motors I assembled, easy, no trim, no leaks. I wouldn’t even consider something different. Follow JW’s install instructions and your set
Scott's views and experiences on the installation is on the money. When we install a one piece seal we put the gap at the bottom of the cap. This way when the cap is put in place the gap will tighten up. Also we apply a small dab of Ultra Grey on the end. Fitting the BOP one and two piece seals prior to installation is important to get them the best you can. I recommend that you install the seal without the crankshaft and get a visual. You can also measure the ID at that point and compare to the crankshaft. Installing a one piece seal is a two person job unless you have an engine puller. Sling the crankshaft and slowly lower into place aligning the seal. IF there is a designed to fit, one piece seal available, I prefer the one piece. I personally don't care for trimming seals to fit unless I have no other choices. We, TA Perf, manufactured a one piece seal for the TA 455 Tomahawk aluminum 3" main cylinder block a few years ago. This seal was also designed to fit the 350 Buick as well. Interestingly it fits and works in the 455 Oldsmobile engine. Also the two piece TA1516 was re designed to be a direct fit replacement for the 400-430-455 engine. It is a Viton material. No trimming needed. No turning the crankshaft to a Ford dimension. We do have the seal surface clean ground to be concentric to the main bearing journals when the crankshaft is being ground. NO need to grind the serrations out of the surface, and I recommend not doing so. Only a couple thousandth's is normally needed to make sure it's true. I have been building Buick engines for 48 years and this is the BEST seal we have had to date. Mike Tomaszewski TA Performance Products Inc
Putting the gap at the bottom (inside the cap) for the one piece would certainty make the process much easier.
Mike, this is great. We finally have a seal that is designed specifically for the big block Buick. myself along with many I’m sure have been frustrated with costly rear main seal issues. Curious, what year did your new seal come out? For those of us who had our crank shafts, turned down to the ford diameter we are committed to still using the Ford seal and will work when done properly. I agree with you on trimming seals and not having a factory edge for the seals to meet is hit or miss
I wouldn't use any type of sealer in the block groove or main cap groove on the 2-piece seal like Jim suggests. I couldn't imagine trying to change the seal with the engine/crank still installed if the need ever arose, whereas with a stock-type pan you can. Offset the ends a little, and a small dap of sealer on the ends is all I ever do.
Man, your older than dirt... Seriously, I would say that Mike is correct here, the seal of choice for most of us should be his new two piece seal. I have not used one, as I buy seals in bulk, and am still working thru my latest allotment of BOP one piece rear seals.. When I run out, I am certainly going to give his new seal a go... But I will take his word for it as rear seals have been a thorn in our side for a long time. He would not be so adamant about it, if he had any doubts. That said: You will, if you build enough of them, find a 455 block with an oversized seal groove.. I have seen a couple.. in that case, the BOP seal is the only one that will work. The oversized seal groove will be evident when you test fit your split seal, and find the ends barely touch, or there is actually a gap between the ends. The seal groove was designed for a rope seal. I have had excellent luck with the BOP dual lip seal. I have used about a dozen, and install them by myself with no other tools. The first one took a little trial and error, but it's really not that hard.. the seal is the first thing that contacts the block, just line that up, and drop it in.. It does take some careful work to install. Here's a few tips. When I read the instructions for the first time, and came across the "put the opening in the top half of the block" I had to chuckle, knowing that would never work. And I would never trust it. I want to physically remove the cap, and see that seal closed up. Like this: Put the opening in the cap side. Do a test fit, once you have the seal sized to the crank, to insure that the ends come together without deflection or bulging. The edges of the seal groove in the block and cap MUST be debured/rounded or you will snag the seal trying to install it. Fit the seal so that when you apply moderate pressure to the Od of the seal, when test fitted around the crank seal surface, you have about a .020 gap. This insures adequate seal to crank contact. The OD is plenty big, that is the strength of this seal.. Make sure you use the high temp grease between the lips as instructed, and I like to put a smear of dish soap on the OD of the seal where it goes in the block, so it slides down into the seal groove in the block, when you set the crank it.. when the soap dries, it gets sticky. And the press in the block is so much, that their is no way that seal is moving. Test fitting is absolutely required. Here is a pic of a recent test fit.. Fitting the seal around the crank.. obviously I have just one hand on it here, the other on the camera. But with both hands, with moderate pressure on the seal, it closes up to about a .010 to .020 gap between the ends.. this is your preload. Then the seal is installed in the block, the cap fitted over it, and we insure that when the ends come together, it does not bulge or distort the seal. The ends of the seal are at about 1 o'clock in this picture, and if they are ground properly, they will not appear because they compress together. I have never used any type of sealant anywhere with this seal, have about a dozen in service, and have had not one leak reported to me.. even had a customer overheat his engine when he lost of fan belt, which is usually the death of seals and gaskets, and his still does not leak. Anyway, just some added info, I am looking forward to trying the new TA seal, if it works as advertised, it will save me work, and my customers some $$. JW
On a side note - I measured about 21 to 23 in-lbs of running torque with just the crank, main bearings, the sticky green Lucas assy lube on the bearings, rubber 2 piece seal, and hi temp grease on the seal. Preload on the seal was about 10 to 20 thou. Do the Viton seals show any less running torque?
