Anyone know the industry standards of acceptable engine out of balance, for the different performance applications. For example:

Indy Car balances to within +- .X gram*mm
Nascar balances to within +- .X gram*mm
ITR "zero balanced" balances to within +- .X gram*mm
Factory B18b balances to within +- .X gram*mm
Etc.......

I would imagine this would be broken down into component level (pistons,pin,rods...etc)and total assembly (pistons,pin,rods,crank,flywheel,pressure plate, H balancer) I've talked to several machine shops and most of the time they say sure we can balance it but don't give any tolerances. I like numbers and really want to know what I'm getting for my 150 clams


Modified by pasaunde at 6:44 PM 7/16/2007


Modified by pasaunde at 9:22 AM 7/17/2007

 

Like FOX News........."Fair and balanced"

 

dont know the standard, but overbalanced is never bad.

 

I just go as accurate as my tools will allow me. I use a scale that goes to the hundredth of a gram. So i balance them to the hundredth of a gram. When i weigh big end / small end i use the same scale and a set of balance bars mounted on a mill which is accurate to 0.0001'' so i make those equal as well. I don't know how my method would compare to the big builders but its as good as i can do so thats where i leave it.

 

Static balancing the pistons, pin and rods is pretty straight foward. I have a scale that weights down to .01 grams so thats where I match the pistons, pins and rods.

The dynamic balancing is where the question arises. I think everyone agrees that a tractor engine that lives between 750-2000 rpm and a performance motor that lives between 7-9K rpm will require a different level of dynamic balancing. The question is what are the accepted limits for the different motor applications?