Engine balance?


Senior Member
Sep 29, 2003
My machine shop just called and said that they couldn't balance my rotating assembly because the replacement pistons (forged TRW/Speed-Pro) are heavier than the factory pieces. I thought that all of the forged pistons were lighter than the factory slugs:confused:. Any one else run into this situation?

Where at in LA are you?? I have used Craigs automotive in Eunice, LA before. They did very good work. PM me and maybe i can shoot you to somewhere closer to you. later, jeremy walters, lake charles, LA

I am in North LA, near Monroe. The engine is at Wall2Wall Performance in Livingston, LA. They have a very good reputation in and around Baton Rouge. Maybe just for Chevies???

I have run into that on a big block Olds, but never on a 3.8 Buick. X5 on the find another machine shop.
OK, I get the fact that I need to find another machine shop;) . I was mainly wondering if the TRW/Speed-Pro forged pistons were really so much heavier than stock?
theses guys obviously have no clue about engine balance, get your stuff and find another shop!!!!

In years past when building street V6's with TRW pistons, I would change
the wrist pins to a lighter piece. TRW pistons come with a very heavy wall
pin to match the stock piston weight. Your shop is probably using the wrong
bob weight percentage figure . If they aren't smart enough to figure that out
then you should probably change shops .Also they many not have the special
bob weights required for a V6.
defetnetly CHANGE machine shops... clueless machinest working on machines!!!! your asking for disaster for your motor!