[mrennie]

I tried the 2 PC BOP in my 455, leaked like a sieve doing the tip test. Problem was the seal groove was not machined concentric to crank centerline, similar to what others have found. BOP makes a nice product, but just not able to use one in my situation.

Installed the Best graphite rope seal and no issues.

[Gary H]

I always used the BOP 2 piece seals until the 1 piece came out. Over the years I've used probably 50 of them. I only had one that leaked badly and that one was because the seal groove in the block was waaaaay off concentric wise. I called Wade at BOP and he said he had never seen one of his seals burned up like that. He suggested shaving down the outside edge on one side and building up the other groove with sealant and try it again. I took his advice and it didn't leak a drop.
After that one, I pre-fit the seal in the block with the cap on and measure each one to make sure it's within spec concentricity wise.

[craigs69]

I've had leaks using the Best Gasket rope and the BOP 2 piece seal. The rope in my 469 had a leak that required me to band-aid it with a vacuum pump until next time the engine is out of the car. My previous 400 leaked horribly with a BOP 2 piece seal. I don't blame the seal though because the seal groove was out of concentric to the bearing centerline by .012".

[Wade Congdon]

While crank center-line to seal groove center-line is mismatch is uncommon it can be an issue with lip seals, it can be easily overcome by fitting the seal accordingly. The seal itself can be used to identify the direction of the offset and the seal can be shaved or shimmed to correct it. We and many customers have been doing this for years. We do not recommend trimming the ends of the seal but rather shaving the backside to fit the seal to the groove. In this we we keep the seal ends square, maintain the correct seal ID, and can shift the seal in the direction we need if necessary.

One last note factory serrations have almost no effect on the lip seals, Aftermarket cranks such as the Eagle can have much more aggressive serrations which can be an issue and shaft diameter should be checked as they vary. Polishing usually will eliminate any issues. It should be mentioned that the "Tip Test" is NOT a valid leak test for a lip seal! Over time oil will migrate under the seal if ANY serration is present. These lip seals are a dynamic not a static seal and will seal when engine is running.

And lastly make sure your engine is properly vented! We have solved countless "rear main "leaks" by making sure the engine is vented well. This includes the PCV in the valley and at least an open air breather, but more preferably a hose from the valve cover to the air cleaner similar to the factory setup. As always feel free to call us anytime for consultation.