Bent Crankshaft?

[WATERWINGS]

I think my other thread dried up "torqued front half to block, now tight", so I will try this approach.

I think I will have to pull my crank and check the runnout, does anybody know the max allowable runout on a crank?

Is it better to chuck it up in a lathe between centers and put the indicator on the center mains, or put it on rollers (on the center mains) and check runout on the top main journal and the lower sealing surface?

If you have time go to the other thread and see if you can win the prize by solving this mystery.

Thanks,

John

[Eagle One]

The possibility of a crank being bent to the extreme it binds up is near impossible. Try this: First check to be sure your not trying to use a shoulder style center main bearing on a non shoulder type crank they will not interchange If all the proper parts are in order check to be sure the center mains are on the dowel pins. Next tighten the front half without the upper and lower main caps down all the way, if the engine turns over it's likely the bottom seal cap touching the crank, if so have about .030 cut of the lower seal cap and reinstall.
Eagle One

[WATERWINGS]

Thanks Noah,

Did you by chance get to read my other post?

It describes alot about the problem, but it is a crank that doesn't have the shoulders, and the bearings say "Flanged Type", I don't have the #, but it is in the other thread.

I'm pretty sure the caps are not tight and pretty sure that bearings are in the dowels, but I will double check tonight.

All spins freely until I torque the cover down, then it doesn't lock up, but gets tighter, but what worries me is that it has tighter spots and looser spots.

The torque wrench on the flywheel shows 2.5 to 3 ft. lbs in the loose spots, and 3 to 4 in the tighter spots.

Please read the other thread if you will, it contains much more info about my symptoms.

Thanks

John

[WATERWINGS]

Noah, the # for the center main bearing is; 31-93495, and it says "Flange Type", is that the right one for the crank without a step (shoulder?)

Is there a chance that one of the new bearings,(centers, wrist pin or connecting rods) have a flat spot on them?

[WATERWINGS]

Crank shaft is not bent

I put an indicator on the two center main journals and the top one runs out .001 and the lower center main only runs out .0005.

The crank still has a notchy feel in different places as it is rotated in the block, (with the crank cover torqued) even with the pistons out.