KB Stage 10 Main Problems

Anyone had problems with hurting #2 and #4 main bearings on a KB stage 10.

I am not hurting the crank but the bearings are starting to move material after 3-4 passes (1/8 mile).

Rods look great. Block is new. Crank mags good
Using a Clevite MS-481M Bearing
.0032-.0038 Clearance
8:71 Litlefield High Helix

 

Crank out of balance, maybe?

 

.0038 seems a touch on the tight side for main clearance. There are other variables to consider (oil weight, dry block, total boost, etc.).

 

mains

I would listen to Robert. Does sound like a crank issue. Don

 

loosen up the main bearing clearance and if this is an automatic car I've been there ! call me I may know exactly what the problem is!

Bob Frigon 315-436-6653

 

Bob,

I will give you a call tomorrow.

I am running Valvoline 60wt. (14 qts)
Lenco Drive/Coan

This crank came out of a very reliable TAD set up that ran the same block, head, piston, rod combination. Had no main bearing problems with that combination.

No state of the art pieces here but all nice pieces. Milodon pump, 2 line pick up on pan, 100 psi at idle. I just bumped it to 120 lbs tonight. No computer.

Brad