Inliners International Forums General Discussion Engines Rear main oil seal.. how tight is too tight?

Okay, I'm back with yet another question. The rear oil seal on this motor is a rope seal. (Best Gaskets). All the bearings plastigauged at 16.5 thousandths to 17+ thousandths against a max of .0025. Crank fit nicely and turned easily. In goes the rope seal. Reading recommendations pro and con, I decided not to soak it in oil but did coat the contact surface with grease after it was installed. I cut the ends on the rope flush with the block on the block half of the bearing and left it proud about 1/32 inch on the cap half. On go the bearing caps. Tightened them to about 35 pounds/ft just to check.. I cannot turn the crank by hand by grabbing the flange. Took the rear main cap out and checked to make sure it was landing level and it seemed to be. Back on it went, checking to make sure it seemed to be straight and level. Back up to 35 pounds. No change in effort. Up to eventually 60 pounds/ft and still no change, but also no tighter. I can take a long screw driver and put it between two of the bolts ion the crank flange and turn the crank. So... Can someone give me an idea how much effort is too much? I really don't want to have to take this thing apart once it's done and running due to a mistake with this seal..

Thanks:
Paul

Sounds about right, might even be loose unless your screwdriver is really long.

I measured the torque on the last 270 that I put together while installing an NOS rope seal from a military surplus kit and it went from spinning freely by hand to between 15-20 ft lbs to spin the crank. I sequence torqued the main caps to 100 ft lbs.

I packed the seal in till it was squeezing over the groove edges and beat it into shape with a large socket and rubber dead blow mallet before installing the crank. Then a dab of RTV on the ends of the packing when doing final assembly.

I have over 1000 miles on it now and rear seal is as dry as can be.

Thanks Ken. That's what I was looking for. I'll measure the torque this evening. I think I'm in the ball park though.

Thanks:
Paul

I have several friends who have had bad experiences with leaky main seals with GMC engines. I have done two this way with leak free results.