Sup guys.
I was wondering.... after a full bottom end rebuild with forged internals, and when they do the balancing, don't they have to TURN the engine with a machine and etc etc to calculate and balance the engine? (kinda like balancing the wheel when new tires are put on)

But if the engine is ONLY a short block, how can they run it with OIL? like no oil pan, or etc etc...???

I mean, doesn't it damage the bearings? not damage good enough to be like a SPUN BEARING, but doesn't it hurts the bearing and the journals?

I don't think they can balance the engine with only 1 or 5 or 10 RPM right? at least around 100 or 200 RPM or even idling RPM. so doesn't that hurt?

any input guys?
Gil

As far as I understand, they balance the crank, flywheel and front damper in a machine. The rods and pistons(separately) are each weigthed and weigth balanced to an equal weight. Each of the 4 rods will weight the same, and each of the 4 pistons will weight the same.
Doing this every assembly of piston and rod will weight the same and will not affect the balanced crank assembly. This is how I understand the balancing is done. If your engine will not see over stock rpm band, I don't see why spend the money.
Hope this helps!

The macine shop wont need your block. The will measure your rods and pistons/rings, enter the data into the ballancer and spin the crank only. Now on the rods they will balence the rods in pairs. Basically oposing Rods are balenced against each other so the opposite ends are equal.

Terry

yea and don't worry about spinning a bearing because they don't need to use any bearing when balancing

I got it now.
So I need to balance the engine, THEN build it.

Coz I thought I have to finish rebuilding it, then bring the entire engine to get it balance.

Thanks again guys