Piston Size Identification (help)

[vasrox]

Ive just stripped down the old 308 and came across this on the piston.
Cheers

[Pub247]

hmm its a bit hard to tell from that dont know what brand of pistons they are they flat tops? or lightly dished? easiest way is to measure the bires or the piston if you got the right micrometers

[vasrox]

The pistons have a slight dish...

[Pub247]

thats what factory piston have once again impossible to tell really i dont think theres a standard for coding parts across every piston manufacturer. Best bet is to measure them or the bores

[vasrox]

I used a micrometer and it tells me 103mm...if that helps

[Pub247]

ok stock bore size is 4 inches or 101.6mm. if its 103mm thatd make it in my book 4.06 inches so that means its been bored out 60 thou (103.123mm) so mate i hope the bores are good and your micrometer is accurate because thats as big as you can go on them. I prefer to use micrometer in thou more accurate and you find that machining is all pretty much in inches and thou.