Quote Originally Posted by DennyW View Post
Example:
I'm sitting at a light, I have a stick trans. A guy pulls up, and wants to race. I up the rpm's, cause the light is about to change. 5 grand, and I'm off the clutch...what impact does this have on the thrust bearing ?? Way more than a hammer.

I'm cruising down the highway, and decide to do some gear jamming...I downshift right at the limit of the next gear. Very quickly, so it slows me down fast...What impact does that have on the other side of the thrust bearing ?? Way more than a hammer in the opposite direction.
Denny - that is not true. You have a lot more potential to damage a thrust with the engine not running then dropping the clutch. You are running xx pounds of oil pressure and it is flooding the bearings with lube oil while it is running, therefore maintaining a cushion. If you are hammering a harmonic balancer on, it might have some residual oil but not a warm continual flow at xx psig. If it's a new build, again, you might have some residual oil or maybe even some assembly lube, but most folks don't use anything but what ever oil they use for break in or operation to put a set of mains or rod inserts in