in ASA the piston number has 3 version,
STD A
STD B
STD C
i know that with resect to bearings the STD is a standard size with a slight variation.
so on the side of the piston i would expect to see a corisponding Letter.
but this is what i have.......
4 pistons with a 2L
IMG_20180419_161910_HDR.jpg
1 piston with a 3L
IMG_20180419_161904_HDR.jpg
1 piston with a 5L
IMG_20180419_161902_HDR.jpg
do these numbers corrispond to size (diameter) of the piston which should match the the original size of the cylinder bores. However my engine block has 5 bores of size 'C' and one bore of size 'B' so 3 different size of piston would be wrong when i say different diameter i am not talking a 0.5mm or 1.0mm over sized piston which would require a cylinder rebore but a fractional difference within the normal cylinder bore range 81.00mm-81.03mm.
or
do these numbers corrispond to weight of the piston which would be selected to match or cancel out some imbalance in the crankshaft.
i dont know i am just taking a complete guess.
i can tell you the 6 Pistons with con rods attached were weighed as 6 individual items
All 2L = 881.5g
3L = 883.5g
5L = 883.0g
so i am not sure what is the correct conclusion to draw.
What do you guys think?
i suppose it could just be the casting block identifier the pistons where made in.
or some kind of batch number, or supplier number, each supplier could have a different number allocated to them.
straw cluching. lol