I need some help ASAP regarding engine balance.

Ok;

So here's the story.

I bought a set of custom pistons, from a manufacturer who shall remain anonymous at this time.

Pistons came in, bore, diameter was on the money. Everything looked good.
Weighed each piston and rod, and they were all on the money.

Sent one rod/piston/pin/rings/buttons to the machine shop with the crank to be balanced.

All came back within .5 Gram.

I go to assemble a rod/piston so I can degree the cam in (I like doing it with 1 piston to make things easier to rotate).

The rod won't fit into the piston. They screwed up at the piston manufacturer, and made the rod width 1.27" when it was supposed to be 1.35".

Called them and they picked them up this past Tuesday, and I just received them today.

Went to check the weight of the piston, and it's 6 Grams LESS than before.

I can only find one neutral source who says it's not going to hurt anything. My preferred machine shop is closed on Saturday.

Can I get a professional opinion from some of you as to run it or have it rebalanced?

Thanks.

 

A small over balance is usually considered to be OK.

 

Crank balance

6 grams should be insignificant. Normally the cranks are overbalanced a few grams anyway. don't loose any sleep over it. together it goes.....

 

balancing

When you balance a crankshaft in a v8 engine the normal procedure is to use 50% of the combined wreght of both pistons ( actually you use a single piston , rings , pins and small side of the rod to balance) SO in REALITY you just changed your bob wieght by only 3 grams. If you consider that most machine shop use between 5-10 grams extra for oil soaked parts , so you are ok.

In Fact don't even worry about that, I have balanced and run cranks between 0 and 30 grams and have not seem trouble DIRECTLY related to the balancing work.

 

Thanks guys.

We got in touch with Wizbang's machinest on the west coast who campaigns a nostalgia a/fueler, and he said the same thing.

Might feel it shake around 9500, if at all.

Since I don't plan on going above 8500, should be just fine.

Thanks for reading and the input.