The Stovebolt Site Forums The Shop Area Engine Shop Rear seal options?

Good...here is what I do, Rick: set the block upside down (main bearings pointing upward). Set in place the bearing insert halves and half of the rubber seal in place in the slot for it. Then cut a common piece of copy paper about 1" wide by 7" long or so. Set this over the rubber seal (in the middle and just so it covers the seal...not on the bearing surface) and then carefully set the crankshaft in place. With the crankshaft sitting on its weight, pull the strip of copy paper out the back end and note the amount of drag involved. If there is drag present, you'll probably be okay. If there is no drag present, lift the crank out, remove that piece of rubber seal and cut a strip of self-adhesive foil tape (the kind the HVAC guys use on ductwork). Cut it the same width as the bottom of the seal slot, apply it to the back side of the rubber seal, trim carefully at the ends and put everything back as before. Now check the drag and keep doing this until you feel resistance when you try to remove the piece of copy paper. The copy paper and the aluminum foil will each be .004" thick. You'll just be moving the seal lip toward the crank surface .004" at a time until it touches and that will give you enough contact to make it all Jake until the seal wears out (15,000 miles or so...hopefully longer) and you'll get to do the same thing again but probably with the engine in the truck. Don't make it too tight, however. Attached are a couple of digital images I took of a seal removed from an engine with about 60,000 miles on it and also a brand new seal piece. You can see how the seal has been worn. That's another reason you want the rear main bearing as close to .001" as possible. Good luck!