scoobyboy1

iTrader: (16)

Well its not my car its my brothers version 4 STi. His headgasket has gone and he is going do the job himself(and some help from a mechanic), what other bits beside the headgaskets would need/or best to be changes while the engine is out.

Also what gaskets would be best as a upgrade. He has been on Roger Clark website and there are composit, multi layer steel and steel headgaskets. is there any other places that are worth looking at for headgaskets!!!

joz8968

iTrader: (13)

STi v.1-4 metal HGs are fine. As are Cometic, Cosworth, etc. MLS ones.

Just make sure they're of the correct thickness to retain the correct C.R.!

Imran21

iTrader: (5)

Hi,
What would the correct compression ratio be? I have a set of 1.3mm cometic gaskets which i would like to use so just wanted to know if this would be hazardous to the engine or will it be ok?
Thx,
Imran

joz8968

iTrader: (13)

I must admit, I thought STi 3/4 cars required 1.6mm thick HGs (but not totally sure). If that's correct then 1.3mm ones would raise the CR - so probably not advisable.

For a definite answer, ask Merlin, JGM, Splitpin, WMS, etc...

Tucker82

iTrader: (7)

Apart from the HG's themselves - it would all depend on what you intend to do whilst its out, and of course whats been done in the past and how many miles its done since...

Normally its advisable to replace timing kit (pulleys and tensioner). Oil/Water pumps?

To take both heads off and replace you would need cam oil seals, rocker cover gaskets, inlet manifold gaskets, valve stem oil seals, maybe crank oil seals, exhaust gaskets if needed. New oil filter/oil & sump washer...

Whats the clutch like? THE LIST GOES ON

Tucker

Imran21

iTrader: (5)

Thanks for the above......sorry if this is a stupid question but why is high CR a bad thing though? I thought these engines were high compression engines anyway??

my94wrx

iTrader: (4)

too high/wrong compression ratio caused by incorrect head gaskets on a turbo engine is bad thing as it will be more prone to det when on boost, and then go BANG!

fastboyslim

iTrader: (2)

Turbo motors are low compression.

joz8968

iTrader: (13)

Old school turbo motors had a C.R. of typically 8:1 or even lower.

As technology has advanced they're now running in the region of 10:1 and above in certain applications.

I think the EJ flat-four turbo motors run c.9:1(?)