Basic Magnum Engine question

magnummopar said

If the machinist swapped pistons, he probably weighted old and new to determine they are super close.

You said you got .002" over pistons or do you mean .020" over? One would require boring cylinders to 4.020" and .002" would be a ball hone.

Balancing an engine requires you to present all rotating parts to machinist at once, prior to assembly. This would be, pistons, rods, crank, damper and flex/fly.

Just call him in morning and ask, there are no stupid questions, only stupid answers.

Click to expand...

Thanks, and I meant .020 over. This was a few months ago and I asked him today to what extent he balanced. He didn't clarify if he had matched piston weights old to new, just that he didn't do a rotate balance. He did have all of those pieces at the time. Oh well...we will see what sealed power says. A couple of sites list the piston at 1.37 lbs, but it looks like that includes the pin. If you subtract what Larry says the pin is supposed to weigh, you get 466.82g, which is 3.17g lighter than the supposed 470g quoted in Larrys book. That seems promising but...

At what point would the balancing need to be addressed? Is 3g too much to ignore? Or is that within tolerance?