The balance results were as follows:

1) Crankshaft was out 27 grams
2) Rods were out 10 grams (max difference between heaviest and lightest)
3) Pistons were within 1 gram (aftermarket)
4) Flexplate was out 2 grams

I was wondering if this was normal or if the crankshaft is usually out this much? The guy doing the balance seemed a little surprised.

Any thoughts?

thats pretty good, take a ford crank down there and it'll be out a pound on the crank and 8oz between rods. really though, thats really good when you take into account it is a factory crank.

Possibly OT lame question but I've always wondered how engine balancing is actually done? I mean do they throw it on a computerized lathe and drill holes in things until it's balanced? Is it something that could be done at home? Do they balance everything with the shortblock assembled, or in individual pieces?

They weigh the rods and piston assemblies, then weight-match them. They take that final weight, and attach a specialized weight to the crank that matches the weight of the rod & piston set, and spin it up on a balancing machine (which is much like a lathe, only built to detect out-of-balance rotation, think tire balancing machine) and drill or weld on the counterweights until it is within a certain range of balance.

Yeah...its like DarkOne said. They weigh all the rods and take the lightest of the four and than make the other three rods weigh the same as the lightest. In my case they had to remove material from three of the rods by just grinding it off. Same goes for the pistons. (Pistons are off the rods when they do this).

For the crankshaft they bolt the flexplate to the back (my car is an auto) and spin it in a machine that can tell where weight needs to be added or removed. In my case weight was just removed by drilling out material in the counter weights. If weight is to be added they would drill a hole in the counter weight and fill it with a denser material (maybe lead or something??).

On a side note....would a stock balanced motor produce more HP (minimal I'm sure) than a stock unbalanced motor? Just curious.

Originally posted by jam013200
On a side note....would a stock balanced motor produce more HP (minimal I'm sure) than a stock unbalanced motor? Just curious.

Not in any appreciable amount, but it'll run smoother and last longer.