18cc Piston Help
Turbo Mini Forums

yep, i did mean 50 thou, its just from memory but I pretty sure 50 thou skim gave me about 5 thou down, although the block had been line bored so you might need even more!

also that was with H beam rods to they could be slightly different length to stock.

and now I think of it that was with a billet crank, so again could be slightly off from a std one so actually I could well be throwing you duff info, but I'm sure Garry needed to take similar off for his build on std rod and crank, with accralites.

still better than the 18cc JE ones that were floating around! they were about 1/4" down the bore!

I had 30 thou off mine. CAM6581 crank, standard rods and 18cc Accralites.

In the 13's at last!.. Just

Cheers, ok looks like they are similar height to add turbo pistons, still tolow though imo

Cheers everyone. I'm tempted to see if anyone has a scrap 21253 kicking about and get it modeled up in CAD.

Maybe seeing how far they can be taken out.

Slightly unrelated, does anyone know what the piston to deck height for a 21253 would be on a standard block?

Edited by danllew on 18th Sep, 2017.

reasonably I would say you can probably get the 21253 out to 12-13cc,

I have taken out the old 73.5mm powermaxes from 10 cc to 17.4cc in the past and they seemed to be ok, bit that was with oil jets

I'm positive mine are at 14cc.

Have oil jets and only 10psi.

Held up now to a lot of abuse.

Cheers again everyone.

14cc would get me down to 8.9:1 which would be manageable I reckon.

Edited by danllew on 19th Sep, 2017.

a Cometic gasket could get you the rest

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

If it helps I ran 20psi on 11cc 21253's at 8.7:1 for years