D, My last A15 rebuild was using the E5 Mazda pistons at 77.5mm, 10:1 compression ratio it worked very, very well, the engine reconditioner simply "decked" the top of the block to compensate for the different pin height.

Quote:Why not just use oversize pistons from Nissan or a regular piston manufacturer like Federal Mogul, Wiseco, etc?

Datrats has the forged Tomei 79mm pistons.

PJZ was getting a custom order (for forged pistsons), but I didn't see a single response that anyone wanted any ...

Why not use the Mazda B6 piston? it's oversize for the A15 (see the exact dimensions earlier in this thread).

Subaru Justy pistons are used by Sunny racers to get 1607cc from an A15, the main thing is the A14/A15 block needs to be milled down (unless you want 7:1 compression).

And of course Pitroad sells the pistons for the 1607 cc A15.

I used E5 pistons in my original engine because it was known to be a common conversion that works well.

I am using B6 turbo pistons in the new engine because they are:

1) bigger (78mm)
2) have 20mm gudgeon pins (same as E5) and standard rods are easily modded to suit.
3) I intend to turbo, so the dish is the correct way to lower the compression.
4) The pin height is very close 32mm (B6) vs 30mm (A15)
5) They are cheap and available.

By the way DO NOT lower your compression by using pistons of pin height such that they sit below the block deck, this reduces squish area, promotes detonation and hot spots around the top of the bore!

If my twin cam engine provides good results I will have a set of forged pistons made specifically.

If I was to build another NA engine I would probably use either Mazda B6 twin cam or Nissan RB20 pistons (both NA)

For my test engine I intend to remove 1mm of rod length via big end resizing and 1mm from the piston crown to compensate for the extra 2mm of pin height.

I recommend anyone interested in sustitute pistons to browse the ACL online catalogue, but be aware that many factory turbo pistons are not available aftermarket.

Quote:

The Justy pistons are a lot bigger than the A12s

The Justy is a 3-cylinder Subaru engine ... the Swift is a Suzuki engine, I don't know if it's the same (The Swift is the same car more or less as the Chevrolet/GEO Metro here in the US, but usually a the Swift has a 4-cylinder and the Metro a 3-cylinder).

I believe the early base model Swift also came with a one litre, three cylinder (here in NZ)

I have been doing some further research on the B6 turbo pistons and it appears there are no oversize pistons available.

Which makes me wonder does anyone have any experience in sleeving the A series?

The actual Subaru part numbers are: S,12006KA082 for the
pistons. The ring sets [I say sets, because a "set" of these is only
for three cylinders], are part number: S,12033KA171

have a read of this if you want more info on the 1608cc Justy pistoned A series
http://autos.groups.yahoo.com/group/d ... messagesearch?query=justy

Anybody else still looking into oversize pistons?

thanks matt I might just hold off a rotary by trying your e5 or the subaru pistons. ill love to deck the block. The more I take off the better as itll make it lighter less is more again I reckon a couple of kilos might come off with the subaru pistons.