Head Gasket.

[alpina]

Hi guys.

It was more of a case of when instead of 'if', but my headgasket has finally popped(ok it maybe a liner, but Im going to confirm this tommorow when I pull the head off.

What the best gasket to go for? Im running 20 psi, and still intend to run that when I put the car back together.

I presume the metal MLS one is the best suited yeah?

[Markey Mark (BD)]

Hi guys.

It was more of a case of when instead of 'if', but my headgasket has finally popped(ok it maybe a liner, but Im going to confirm this tommorow when I pull the head off.

What the best gasket to go for? Im running 20 psi, and still intend to run that when I put the car back together.

I presume the metal MLS one is the best suited yeah?

The normal blue seal gasket will be fine for that boost mate

[Ian S]

My standard HG from GSF (as mentioned above) didn't even creep a tiny bit with 25psi (manifold) boost over two years. And before then neither did the OE Renault HG with 15psi (manifold) boost living at 7500rpm for 10 years or so.

HG's don't break when in a competently assembled and set up engine. It's users who ruin them.

[Rob1980]

Don't forget that head gaskets blow for a reason, they are kind of like a fuse.

Make sure that your carb and fuelling are correctly set up to run 20psi. Have you got an AFR gauge?

[michael tierney]

:(mine blew recently at 16psi @manifold........pinking or detonation(extreme pressure increases /spikes in chamber pressures)...that's what does it......and after doing it i'd say my rings aren't too good either:(

[Brigsy]

My standard HG from GSF (as mentioned above) didn't even creep a tiny bit with 25psi (manifold) boost over two years. And before then neither did the OE Renault HG with 15psi (manifold) boost living at 7500rpm for 10 years or so.

HG's don't break when in a competently assembled and set up engine. It's users who ruin them.

I would agree with this. A half decent gasket will withstand 25lbs + with ease providing the engine is well set up.

[alpina]

Right,

Pulled the head off today and its a cracked a liner. :(

[Rob1980]

Right,

Pulled the head off today and its a cracked a liner. :(

How is your carb set up mate? Do you know your AFR's? The head goes for a reason and it's generally fuelling. Do not just replace the liner and head without curing the underlaying problem or you will be paying out to replace them again very soon. :agree:

[alpina]

Hi rob .

Put it this way, I nailed it in 4th on the way home from work with 95 in the tank.

Earlier on in the day I ran out of fuel on the way to work, and managed to Coast it into the nearest petrol station, some esso with only 95 on tap(I've only ever put shell v in). Left work later and decided to nail it in gear on the a38 back to my place, felt it miss a couple of times so I let off but the damage was done by then.

It was always running rich, which to my ignorance I presumed it would be ok for the occasional blast.

You live and learn I guess. Hopefully I can wake up early enough to drop the head off at the machine shop. I'm lucky enough to have a couple of them within walking distance of my house in Bristol :)

[Alex]

Your fuel bowl probably emptied.

[GTphil]

You will probably want to make sure your head isn't overly skimmed by measuring it while it's off. 73.5mm should be standard.

Anything below 73mm with standard compression pistons and it would need to be very well set up fueling wise.

Alex is probably on the money with the carb bowl emptying. Particularly in fourth gear.

Do you have any fuel supply changes like a better fuel pump and fuel regulator? This will help or infact cure the bowl emptying issue.

Worth checking all the vacume lines for splits. And making sure the AEI ignition unit is working as it should.

People are correct above, you will definitely want to find out what's caused it. Check the gasket very carefully for marks, and the plugs also, even the tops of the pistons can all give clues as to what went on to blow the gasket.

:edit:

I mean crack the liner:wasntme: