Clarkie GT

y is there 2 thicknesses of head gasket?
and which 1 would i need for a 1995 WRX wagon?

i hope its not a case of measuring your old one, cause that was binned monhes ago

f4la k

iTrader: (1)

For diffrent compression ratios, but you would need to speak to an engine builder with your measurements to find out which one.

Clarkie GT

ok pal... well... i understand NOW that wagons have a higher cumpression ratio to saloons, so the fact i fitted a z4 ecu off a sti saloon may have been the reason a piston decided to melt.

sound like i need the thinner one...

alcazar

iTrader: (2)

Not afaik, they don't Speak to an engine builder, Harvey, David at Api, Alan Jeffrey etc.

Basically the different thickness gaskets are used to keep the cr the same even when heads and/or blocks have had to be skimmed.

Your piston melting sounds more like under-fuelling, running lean, whatever you want to call it.

What else have you done to the engine/ecu, and did you have the map checked?

Clarkie GT

no, the ecu has a ESL daughter board from power engineering, mapped at 1.1 bar, on a car with exactly same spec as mine (decat & filter)

as a precaution i'm haveing the injectors cleaned, converting to paralel fuel rails & fitting a walbro fuel pump

i know i should get it mapped properly, but a FMIC and 440cc injectors are plannned so dont fancy paying to get it mapped twice...

alcazar

iTrader: (2)

I know how you feel, but trust me, not getting it done can work out a WHOLE lot more expensive

ZEN Performance

If you use the thin gasket the pistons will hit the heads!

The 93-98 engines all used a 1.6mm gasket as the top of the piston protrudes past the block at TDC. The Phase 2 engines and onwards have a piston that's about 0.3mm below the deck at TDC and uses a thinner gasket to suit.

If you put phase 2 style pistons in an early engine (not unusual) you should consider the cosworth 1.1mm gasket as that will give a reasonably tight quench but not bump the compression up too much as the earlier heads also have a smaller combustion chamber.

Everything should work with everything else.