Line boring problem!

T

Tom Elliott

Senior Member
After line boring the mains we found that the Babbitt on the caps were extremely thin. Anyone run into this problem? Maybe someone had filed the caps down at one time. Is there a way to measure the caps before hand to make sure they are ok before pouring? Thanks, Tom
 
Only used the .016 pack, not going to do that again. But even with another .016 added the Babbitt left in the center cap would be less than a 1/16. Never ran into this before. Afraid if we cut in oil grooves we would be down close to the cast cap surface. Thanks, Tom
 
Tom, can you mic the cap thickness where the main bolt goes thru to see what they measure. Also, what machine are you using to line bore this, ...and any chance you did not get the alignment fixture properly centered?
 
I use a K.R. Wilson fixture, the block side looks good and not any extra Babbitt. I am sure it was centered. I have a few extra caps around and will measure them like you suggested and see what differences there might be, Thanks
 
Tom Elliott said:
Only used the .016 pack, not going to do that again. But even with another .016 added the Babbitt left in the center cap would be less than a 1/16. Never ran into this before. Afraid if we cut in oil grooves we would be down close to the cast cap surface. Thanks, Tom
Click to expand...

Just use the .032 thousandths shims, or like I said in the other post bolt the cap on and put in what ever shims to make the hole round, before you pour.

What ever you end up with for a crankshaft bore, when that babbitt is wore .006 thousandths or more, the bearings are shot anyway.

For groove depth, the grooves can go all the way to the steel tinned caps, also on the early steel tinned rear cap. If the babbitt falls out, it is not stuck anyway.

The block, and cast steel rear cap, you have to hold the groove depth to 1/2 the thickness of the babbitt, any more it will crack in the groove, especially if it wasnt peened right.

Herm.
 
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