If I clean up some casting ridges on my connecting rods, crank, etc. will it be necessary to have the rotating assembly balanced? How much grinding can I get away with here before re-balancing becomes necessary?

 

a 1-2 gram difference is still considered balanced. Picture 1 gram of iron. It's a decent amount. Just removing the sharp edges shouldn't change it much.


not bothering to reply to both of your threads, so, I got an aftermarket balancer mostly for the engraved timing marks. I don't think there's a huge gain to get, unless you are racing and *need* an SFI one.

 

Yes.

Basically none.

While "none" is not strictly true, as someone will most likely point out, it's in the class of "if you have to ask, you shouldn't be trying it at home". I don't know of any way to specify, over the Internet, how much material can be removed from what places (all material is not equal in this regard). What you mean by "clean up casting ridges" is another variable; that means vastly different things to different people. People with experience doing this, would know where to and not to touch things, and how much. Without experience, you are certain to destroy the value of the balance job you already paid for (i.e., you will throw that money into the trash can).

Things like that should be done BEFORE balancing. Balancing should be the VERY LAST machining step before assembly. If you're going to do more machining on ANY moving parts, get it re-balanced AFTERWARDS; learn the lesson; and you won't make the same mistake next time, of jumping the gun and doing things out of their proper order.

 

A gram of iron is about 0.127 cc. It doesn't take long to grind that much off.