Anybody know what the diameter of the seal surface on the crank is suppose to be on a big block.

I'm fighting a rear main seal leak and am wondering if maybe the seal surface was turned too small at the factory. I can't make this thing run 20 minutes without spraying oil half way to China! Three different seals now in the last 4 days.

I've pressurized the motor with about 1-1/2 PSI air and sprayed soapy water around the rear seal. It looked like a bubble bath. I could actually hear the air hissing out on one side where the two halves of the seal are suppose to mate up.

Anyway, I measured the diameter of crank at the seal surface, best I could with the motor together and in the car. It appears to be 2.820" and I can't find the factory spec.

i just measured 3 cranks and they're all between 2.812 - 2.820
what type of seal retainer are you using?

Hey Dan

Thanks, I've got the World aluminum block and the seal retainer it came with.

what kind of seal are u using??

i had a world hemi cast block years ago that leaked from the rear seal. after dropping the pan 4 times, i discovered the groove in the block was machined too wide & not centered to the crank. the seal would slide in real easy, then get snug when it was about 1/2" from being flush with the block. chrysler wanted it back & sent me a new one. just sayin. seeya.

I just checked my AERA crankshaft manual and it lists it as 2.812 - 2.815

The World blocks had what was in my opinion a " fair" seal retainer and also some blocks had a problem with a machining process that must have been just wrong. Where the retainer slides in, there was a noticable ridge or step that was towards the bottom half of the side walls. Something is just not right, you shouldnt have that much trouble.

Hope you get it figured out.

Here is a little reading for you....hope it helps.

https://board.moparts.org/ubbthreads/show...rue#Post6895629