Just got back from pistons auto and Lindsay the owner says he can get 76,77,78,79mm pistons. They have a 20mm gudgeon and sit 1mm shorter than a15 ones. Does anyone know if with a closed chamber a14 head it will give me a compression less than 10:1?
Otherwise If I need to open the chambers?
Is it safe to open up the rod journals to 20mm to suit the mazda pistons?
Im going for the 78s cause itll give me some room for honing on rebuilds.

Are these decent pistons or just std cast ones ?
I have a 77mm bore and am searching for some better quality units.
I have enlarged the gudgeons to 20mm as I am using UC Mazda pistons in mine.

JE make good pistons they do custom stuff too but i am sure there would be anothere engin out there that has same bore and gudgeon size
DAVE

Pin size not a problem, but mazda piston is longer, also look at weight, lighter the better. Longer skirt area increases drag and operating temp also may interfear with shaft counter weights. A15 piston lenght is 65mm mazda is 77mm.

The pistons and rings from Pistons auto r cast for the 240 bucks but forgies cost about 1200 and can be up to 79mm with your choice of sizes for the conrod journal. Casties are not that nastie and can handle about 8500+ revs on 10.5:1 max so Ive been told with all things being right. The new ford ba xr6 turbo has all cast crank, rods and pistons for cost cutting and still pumps 200+ kws. The height of the piston on the mazda one is 1mm less so 64mm height not 77 (I think youre probably mistaken for the commonly used mazda piston width in a14/15) and you would need to balance the engine from clutch to water pump anyway if youre modifying an engine. So been 64mm high I wonder what it would b with the closed chamber a14 head from a pulsar fwd?
The 77 bore is common 1mm overbore but for 1567cc go 78mm and still have room in the future for plenty of honing Im going 78 or 78.5 as the 79mm leaves so little meat in between and is just over 1600cc which is over 1600 and limits you on some hillclimbs or other classes.

PISTONS AUTO IS GOOD

i like them blokes, i live just around corner, where are you D

Im in Pascoe Vale and envy u for having all the Datto stuff on your side of town.
Well I will get the 78 mm pistons then if their stuff is rosey.
Being thinking whether I should get the pistons ceramic coated and the rods and crank nitrided?

dunno, whats the application?

what motor?
turbo?
ect. ect.

dimlight did all ceramic coating and that to a motor he was building, then he sold the motor b4 using it (why ill never know)

but there pics in the gallery of that which are pretty cool and he could probably answer your questions

HE WHAT!!!!!
It looked so beautiful and pocket killing!
Mines just normally aspirated A15 and looking for a cam to work from 3600 - 7200 but nothing that comes in like gangbusters.
However I dream of adapting 42mm motorbike injection with a cheap Delco Camira setup to run a lumpy 4000-7500 rpm cam.

I'm using Mazda UC pistons
4KRY2699 from the ACL catalogue
I have milled the tops off so there is no dish left at all.
Mazda pin height = 30.58
Piston length = 62.48
I have A15 crank in A14 block
0 deck height
12.9:1 static.
I really think I need valve reliefs cut however 2 engine builders have torn my motor down and rebuilt it and say its O.K.Then again I think the cams way too small.So maybe thats why I didn't need any valve reliefs.