thinner head gasket & flywheel types

[olidaviesuk]

Hi All,

In the process of putting my GSi 1600 engine together, would ideally like a thinner head gasket to raise compression ratios a little bit.. SBD do one, but ?195 for a head gasket is a little excessive.

Someone I know suggested that I use one from a Daewoo 1500 as they are a vauxhall engine and use a very similar gasket, apparently the gasket is half the thickness of the standard one.. - ive roughly worked out this should raise comp ratio to 11:1 hence a fair bit more power for very little effort. :)

Has anyone on here done this themselves? and have any idea which paticular model it comes from..

Also, is the GTE flywheel the same as the GSi

Cheers

Oli

[Stuart]

how about a ?20 skim and use a std gasket....

also what are you doing about ign timing as with the ecu controlled stuff its possibly going to det if it advances too far on 11:1 or more.

[olidaviesuk]

don't really want to go down the skimming route if I can avoid it. Hence was going to try and use a thinner gasket.

Ignition timing shouldn't be too much of a problem as im using aftermarket MBE management controlling ign and inj, also using the later C16 coilpack and doing away with the dizzy.

Other than the Cosworth Pistons im pretty much running Grp A spec ancilleries side with the larger injectors etc, hence wanting to raise the comp, but without spending ?500 odd on new pistons, had considered decking the block or skimming head but would mean a pretty big stripdown, which I'd like to avoid if poss :)

Also have a feeling that the Grp A cosworth pistons were pocketed due to valve clearence issues can't remember though...

[Philsutton]

to be honest skimming is the best way to do it, if you go for a waffer chicken head gasket you'll be changing it every day.

[Stuart]

you dont need to do "that" much of a strip down for a head skim....

[craig green]

I'd skim the block or change the pistons tbh. Why dont you fit some pistons from another model. A bit of research ought to point at some pistons that will fit.

Ive heard of Toyota ones being used in an E16SE before.

Its not really grpA without the Cossie pistons really. I'd skim the block before the head mind you.

[olidaviesuk]

don't really want to go down the new pistons route if I can help it as pretty happy with the bottom end that i've got as had a fair bit of work done to it and its nicely run in.. mainly just after raising the compression slightly, without having to go down the route of measuring cylinder head volumes, skimming etc

have done a bit more research and the gasket is from a 96-98 daewoo nexia 1500 (thanks autodata :) ) - using it approx raises the compression from 10.0 - 1 to 10.8 -1 which although isn't quite what the group A cars run is quite a good compromise without having to get involved with decking blocks etc..

My only concern is the possiblilty of melting the standard pistons, but I suppose thats going to be down to the quality of the map that I use..

[Stuart]

you can even melt forged rude ass pistons if youve got a monkey mapping it..... and someone who is very very good can make std pistons outlast forged (done by the monkey).

a 0.8 change is going to offer you next to feck all in gains for the effort involved lol. plus if your taking the head off you ideally need to get it faced bare minimum so you might aswell get a bit of a skim done.

but it does sound like you prefer to be lazy and not measure/check your engine to get the best out of it while its in bits etc. (it takes 30 mins to measure head volumes lol)

[olidaviesuk]

completely agree with you about monkey mappers, going to have to do some serious research about who to use!

First time i've contemplated seriously tuning a NA lump, all my experience comes from tuning turbo'd engines.. The engine work that gets you the biggest gains in NA cars is mostly amongst the last things in the list when tuning turbo cars. :wtf:

Unfortunatly the championship im going to be racing in (hence putting the engine together for) are pretty strict to what you can and can't do and have been know to get competitiors to strip down engines to have all the parts measured etc.. fortunatly there are some 'grey' areas.. hence if I can make little gains everywhere it should make for a fairly quick engine... :)

This is why im trying to avoid skimming the head and the block as they've been refaced twice already and the standard tolerances are getting a bit close for comfort.. :roll:

[Stuart]

furry muff. atleast yovue explained why ;)

for mapping where abouts are you?

[olidaviesuk]

im in south east london, though i suppose im going to have to find someone whoes familiar with the MBE kit to start...

[Stuart]

road and track in rainham.

just over the river in essex. but hell the know their stuff. known as the two steves ;)

[garyc]

If I were you I would speak to the scrutineer and find out the values of measurements that are made for the engine you are actually racing. Racing rules often tend to be down to interpretation or implied. They may even measure your head gaskget so could be in trouble any way? What do your rules actually say?
The other thing you could try is a headsaver gasket which are used as a secondary gasket when a head has been skimmed too much, I dont know any more details about them but a decent engine shop/ parts place should be able to help.