Here's what I just found on my block after having two ropes and one viton seal leak (all within a month of each other!!) I checked the dimmensions of the seal groove. And although it was round, it was NOT on the same centerline as the crank!! The depth of the groove from parting line was 0.020" deeper in the cap than in the block. That taken into acount with some other dimmensions meant that the viton seal was not, or just barley touching in the cap half. I don't yet know if it is fixed, since I'm assembling the motor again this afternoon. It really sucks, cause you have to take the crank out to check this. But in my case it was a good thing, cause after doing it three times with out taking the crank out, I did this time and also found a broken ring. This was probably causing all the crankcase pressure blowing the oil past the seals.
So why is it that Pontiacs are such a pain to seal here?? I've done zillions of SBC and BBC with no trouble at all.
Good luck
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