.040 Pistons for Mazda

[RacerBowie]

RPM Machine, in Utah I believe.

They are stock replacement cast pistons. Cheap. Quick shipping.

http://www.rpmmachine.com/engine-rebuild-kits.shtml

.040 in stock, at least they were a month ago.

[Andy Bettencourt]

Or just go with the .020 from Mazda. Cheap and available and it gives you some room for a second crack at the block.

[RacerBowie]

Or just go with the .020 from Mazda. Cheap and available and it gives you some room for a second crack at the block.

Which comes in awful handy sometimes.

<--- on his second crack at this block.

[JohnW8]

The block already .020 over but the rings don't seem to be sealing real good. 12-14% leakdown on all four cylinders. That doesn't seem like much until you consider 5-6% is what it should be.
At Barbers I had to empty the oil catch can twice. Lots of blowby, but no nasty debris left on the plugs.

They say you can't polish a turd but maybe you can rebore one.


Thanks for the input.

[Z3_GoCar]

If there's too much wear in the cylinders the rings won't seat correctly and the motor will drink oil. If you've changed the rings you need to have the bore measured for wear, specifically for roundness through out the bore.

[joeg]

Jim is correct but a worn bore/ring will make the engine act more like the Exxon Valdez (push oil out into dump tank or just plain leak more so than burn it).

If you are filling the dump tank, that is classic blow-by from rings/worn bores.

[joeg]

It can also run a long time in that condition but you will need shorter races and a bigger dump tank!