crankshaft thrust bearing alignment

[moparquest]

Hey, guys. I just layed a crankshaft in my 440 block. Can anyone tell me how to tell when to tell when the thrust bearing is correctly aligned? I tried moving the crank back and forth with screwdrivers to properly seat the bearings before tightening the #3 main cap nuts. But i couldn't tell much about it. I measured .002" clearance between the #3 main bearing insert thrust surface and the crank after tightenting. I'd sure like to feel sure I have good alignment before proceeding.
Thanks in advance for your help.

 

[Cranky]

I usually take a heavy rubber mallet or dead blow hammer and whack the crank back and forth before I torque the main down on the thrust bearing. .002 is pretty much the minimum on shaft end play and I like to see at least .003

 

[67 B-body]

Best bet is to use a dial indicator on the nose of the crank. Use your pry bar to pull it all the way back and "0" the gauge, then pry it forward. The true reading will show on the dial indicator!

 

[moparquest]

Today I loosened the #3 main bearing cap. Then I used a rubber mallet on the ends of the crankshaft. Then I pried the crank forward and tightened the #3 again. I measured the end play on the nose of the crankshaft with a dial indicator. I also stuck a feeler gage between the thrust bearing surface and the crank. I measured .0035" with a feeler and the end play was .075" with a dial indicator. If the thrust bearing isn't seated now it's not for lack of effort....

 

[snakeoil24]

End Play

Today I loosened the #3 main bearing cap. Then I used a rubber mallet on the ends of the crankshaft. Then I pried the crank forward and tightened the #3 again. I measured the end play on the nose of the crankshaft with a dial indicator. I also stuck a feeler gage between the thrust bearing surface and the crank. I measured .0035" with a feeler and the end play was .075" with a dial indicator. If the thrust bearing isn't seated now it's not for lack of effort....

Double check the end play number. why did you loosen the 3 cap then move it?

 

[moparquest]

Oops. I meant .0075" instead of .075". Sorry. I figured it would be easier to pry forward if I loosened #3.

 

[67 B-body]

You are supposed to always have the thrust bearing cap loose when you pry it back to line up and seat the bearing.

 

[moparquest]

Dang it. I was measuring endplay incorrectly. I'm still having issues with this cank installation. I've tried all the techniques graciously offered above. Now if I loosen the #3 main bearing cap I get end play of .005". But when i torque the #3 main I get .003". Is this normal? Your continued help/advice is appreciated.

 

[mopar367]

No that isn't normal. I just laid the crank in my 440. What I did according to the manual was, lay the crank in the bearing halves. I slid it back and forth by hand so it seated the thrust bearing bottom half. Then I hand tightened the main caps. And slid the crank back and fourth a bit once again. just to seat the thrust bearing before torqued. Before torqued the endplay should be the same as after the caps are torqued. If not something is not right.

 

[mopar367]

I wouldn't feel comfortable unless I had at least .005 thou endplay. Too tight is bad.