Bruce is correct in that the front stack is where so many rebuilds go down the drain. So the rear counterweight goes on first. Also once you do this a few times it can be just a personal choice. If the front bolt is not torqued down on a completed (correctly) front stack, rotating the engine through horizontal often allows that pesky spacer sleeve to move foreword just a bit and then the rear thrust bearing drops down behind the spacer. Now when you torque up the front bolt, you crush that bearing. Then you have zero end play and pieces of bearing

adrift in your new engine.

 

Do not use the front counterweight to hold the crank still while you torque anything. The keys are soft and can be deformed. The counterweight can warp a bit and upset the surface where the bearing washer sits.

 

When checking end play,with the front of the engine still pointing up on the stand, just push up with your hand on the rear counterweight. Do not pry up on the front counterweight with a screw driver. The thrust plate is flexible and you may see a totally bogus measurement on your dial indicator, when part of your measurement is plate flex.

 

In racing engines I used double lip seals on the rear counterweight installation. A stock looking rear main seal with a spring loaded lip facing the engine and a non spring loaded lip facing aft or, away from the engine to keep dirt away from the inner seal.

In any case a bit of lube oil on that seal lip gives it  a head start on a long life. Just a bit, as oil attracts dirt, the reason for the rear facing seal lip. Not needed on airplane stuff.

Piece of cake.......................Lynn E. Hanover

 

That's what I though, although Bruce says to tighten the rear nut (and admonishes you to not invert the engine) before the end-play testing.

I actually made a counterweight holder of a piece of steel which also includes a removable counter torque angle.

 

thanks

 

Rich