1.9 & 2.1 difference in pistons

[bratjie]

Can anyone please tell me what the differences are in the 1.9 and 2.1 pistons, I purchased pistons for my 1.9 but they do not look quite like the old ones, maybe the spares place gave me incorrect pistons?

[buildabiggerboxer]

The 2.1 pistons are shorter, back to back them on a pin and see the difference, it roughly translates to the extra 7 mm stroke of the 2.1 resulting in the wrist pin being located higher in the piston by 3.5 mm.
Aftermarket Chinese repros have a lower crown and consequent deck height and compression pressure which seems to vary somewhat.

[bratjie]

Thanx, looks like I have the right piston then, previous builder milled out the combustion chamber to lower compression for boost, now I will at least have std c/r with 5psi boost,