Piston weight

[Andy Mac]

Hi,

Are the forged SFC1000/Corsa pistons the same weight as the standard RGS items?  I am just guessing that they would have been to avoid production line crank balance issues between the various models?  Is that correct, as I am wondering about crankshaft interchangeability?

Cheers, Andy

 

[jlo]

Yes, there are differences in weight between pistons, even those fitted by the factory and they didn't change the balance factors... The Assos were by far the heaviest.

 

[redax5]

Andy,
I weigh and record piston weights when assembling engines, it is not uncommon to see a variance of 10 grams between Mondial pistons in the same engine.
Have seen higher in one engine, 32 grams from memory, but it looked like it had a piston change on one cylinder at some stage even though they were all Mondials.

95% of the engines I build require a rebore thus get new forged pistons, matched sets with a variance of > 1.0 grams.
the 80.5mm Ross pistons roughly weigh the same as the Mondial 75.0mm pistons with the Ross 75.5mm pistons significantly lighter.
when installing the Ross 75.5mm pistons onto a stock 1000 crankshaft there is no noticeable difference in vibrations, I'd say the engine is smoother.
Probably because I balance each Conrod/Piston/Ring/Pin set to the others, something the factory never did

You will not notice a difference
Red