ok here is another question.

i have a set of nippon 82mm p72 pistons that i had to smooth off some sharp edges around the intake reliefs last night. in the process i put them on the digital scale, here are the weights.

297.8g
298.3g
298.4g
298.1g


ive never really measured piston weight before, is there a general range of closeness that they should be?

 

1 gram is good. Looks like you are well within that. But, if you have the time and the tools, why not shoot for perfection?

 

^^x2

 

I personally have always found the mean and used +/- 1 gram being in the OK range. So that is a 2 gram window to be in. Since these engines are zero balance engines the closer the better. If you do the math on what even 2 grams added weight does to a rod at even 10k rpm you will see it isn't THAT big of a concern. Still, to minimize engine harmonics even weight is always best.

 

As far as rpm im using itr dual springs and this is my daily so I will probably set the limiter to 8300-8400. Itr cams seem to peak right atound 7800-8000 n/a anyhow

 

If that is all you are turning then you are more than good. I have seen used OEM sets be off by over 5 grams... and I am sure that's not the worst out there.