I was told there are mazda pistons that are 1mm overbour that will fit in an A siries without modification other than the bour, and that they are cheeper and more redaly available. if so wat model car or motor are they out of?

Thank's, Connor.

you can get datsun a12 1mm over in
dished or flattop from MD spares in
Melbourne, available no worries $150

Sorry, I should hav specifide. for an a15

not sure for a15 give them a ring
(03) 9553 0388

The word you want is 'oversize' pistons so you can 'overbore' your block.

If the Mazda pistons came in a standard 1mm oversize & worked in an A15 without modification, then they would also be listed as A15 Datsun pistons.

Since you need to modify either your rods or the pistons in order to use them, they would need to be significantly 'cheaper' & I don't think they are.

If you want to push your 76mm bore size out to 79mm & run flat tops, then certain Mazda pistons are often used, but the valve reliefs are in the wrong place, so this will need to be addressed too [at extra cost] In fact, to make this an economic proposition the pistons would need to be almost free.

I bought a set of non genuine second oversize A15 pistons [77mm] for about, ummmmm, I forget, it was either something like $150 or $250. I suspect that the stock 'replacement' Mazda pistons will be a very similar price to the stock 'replacement' A15 ones.

No wories thanks, I'll look into some nissan genuine ones then, thank's

Is A15 piston a full float type piston(using snap ring)...??
I heard tat rb20 piston were 1mm larger than the stock A15 piston....

the mazda pistons u tork about are out of a uc the piston pin bore is the same size but they need to be machined down a bit cant remember egzact size but u can get a15 over bore pisons all the way to (60)thou (77.5mm) over but there not flat top so u would still have low compression why not try some j16 pistons witch are like 79mm and there dome top but the compression hight is like 32.9 or something like that standar a15s about 32.1

i use a mazda piston which is a E5 40thou over with a gudgeon pin of 19mm if i remember right, these pistons are machined to take small lip off the top about a 3cc dish, they sit 30 thou below deck height. to use these you bore your a15 80 thou=2mm and enlarge your conrod smaal end 40thou=1mm
about 9.8:1 comp 1580? cc
wouldn;t do it again, work = small gain

i reckon shave the head deck the block flat top pistons std bore. cheap and fun now go play

Sunny,u mean juz sdt bore but flat top piston...??
Wats the compression ratio...?
How many mm will b the best to shave the head...?
The reliabilty is to b consider too...
Tq...