ive got a rs turbo engine and ontop has got pistons with numbers on them

3 of them has no2 and 1 has no1?

why

 

You have non-matched pistons.

They should read 1, 2, 3 and 4.. the order of fitment and firing. Don't use it like that as you will get 1 firing them three firing next with no 3 or 4 and will be lumpy as fook.
























Nah, I'm joking mate. Not a clue..but a free bump for ya.

 

something to do with balancing?

 

i know for a fact these are original pistons as the engine has never been split until now

 

They're a std sizing code that the factory use, IIRC.

 

correct, iirc cossie blocks were selected by no. 2 or 3 in the block size, pinto blocks could be 1-4!