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The engine that i started out with was from an early 325i '87 (i think). however when the block was with the machine shop getting decked one of the pistons got mashed up on the machine. dont ask how lol

i got another couple of pistons from a boy up the country same make KS but from a later 325i (post facelift i think)
thought they were the same until i was cleaning them tonight and i've noticed a difference in the valve cut outs my original pistons have a noticably deeper cut out for the valves



dimensionally they seem fairly similiar and weight ways they would probably all balance up

would there be any issue with me using one or two different pistons is their a difference in compression ratio? what effect would this have?

any thoughts would be greatly appreciated

Willy

The earlier 325 engines (chrome bumper) have the higher compression engines and therefore the pistons are different.

I think all six pistons should be the same but there are more informed people on here that can probably tell you better.

guys on the zone say left piston is higher compression and definitely do not mix. so i'm after a single piston the same as the one on the left guys if anyone can help me out.