Well It Leaks AGAIN!

superchargeddrt said
No the dip stick is staying put. This will be the third main seal.
The first one leaked on the dyno and we thought it was a oil pan gasket issue. We changed the pan gasket and while doing so managed to break a grade 8 bolt in the oil pan. This was surprising because we didn't put any serious torque on them. We had already put permatex on the gasket area and it had started to dry because it took us about an hour to get the bolt out. We decided to install the gasket anyway and we reinstalled the engine. When we started the engine we had the same leak. This was really frustrating and I was about to quit and let it go until the next year. We put dye in the oil and used a ultraviolet light to see where it was leaking. It looks like the oil pan again so figuring that it might have been because it took so long to get the oil pan gasket tightened down that it might have caused the pan gasket to leak. Remove the engine again and we put yet ANOTHER pan gasket on. My buddy Larry suggested the we install a main seal but I didn't have one and it looked (according to the dye) like it was the oil pan gasket. We reinstalled the engine AGAIN and guess what?......It leaked again! I ordered a new seal from Superformance, installed it and the leak was fixed for several months and I thought I had it beat. Now I was only driving it to and from our local car show and the speed was kept to around 60 MPH or lower. I think that the combination of extended 70 PSI oil pressure and heat caused another failure. I ordered the adjustable PCV and we're gonna pull the engine one more time.

The specifics on the engine are:
418 Stroker
Molnar Crank
10.55 Compression Ratio
Superformance Main Seal
Stock style PCV
Breather on the other valve cover.

I hate that you have to pull the engine again, but this time, be very purposeful in your disassembly. When you pull the rear main cap, look at the seal. I'm going to bet (if you don't have a ring seal issue) that the problem is going to be you didn't trim the ends of the seal.

Some guys LOVE to clock the seal with the ends above and below the parting line. I've never done that, nor will I ever.

It won't fix anything. If you did clock it off the parting line, slide the seal around until the ends are at the parting line. Then measure how proud the ends are above the parting line. You only need .010 or so proud on the block and cap. For a total of .020 at most.

If you have more than that, it will push the seal out of round and make it leak. You see this with line honed blocks. I started with a brand new block and by the time it was ready to go, I had to trim my seal.

I still prefer a rope seal. It takes more torque to turn on assembly, but it takes less when you get a few minutes run time on it. If you are pulling crankcase vacuum, you have to use a rubber seal.