88 7mgte head gasket help

[AndrewI]

hello, have a few questions on headgaskets.

1st is it easier to pull the engine to perform this job?
2nd, I noticed comments on steel headgaskets? why are they frowned upon?

thanks
Andy

[Jeeves]

Andy,
I'm going to address your first question last.

2) Steel HG's (Often called Metal Head Gaskets or MLS (Multi-Layer Steel) HG's) are only frowned upon for stock replacement when power levels don't require them due to the work you have to do to prep the block for them. They requre the head AND the block to be machined. So, to replace a composite head gasket (Stock HG's are composite material) with a Metal HG you'll have to make the block flat by machining it, or lapping it which requires a special tool (not cheap, far from common). These are about the only way to make the engine ready for a Metal HG. Lapping can be done with the motor in, machining obviously cannot.
1) So, with the above in mind. If you're replacing a stock HG with another stock HG, you can clean up the block easily enough for a composite to seal while the motor is in the bay. However, to do a Metal HG job, it's much easier to pull the whole thing.

[AndrewI]

hmm thats good to know
how much boost can a stock HG hold?
factory is between 4 and 6psi?

[bgrieger]

Some reliably hold to 10-12 PSI for a number of years...most don't last all that long at the higher end of that range.

[Jeeves]

Mine started to develop serious signs of detonation in less than 2500miles of 11psi on a stock head gasket. Naturally Tune has something to do with it, but I didn't have the logging capabilities to tell what my tune was like then.

[bgrieger]

I got 5 years and 50,000KM running 10 PSI on my stocker after I replaced the original...actually, it's still fine but the rings are starting to smoke so the whole works is on the way to the builder...

[Jeeves]

Same. I quit dickin' with it and I'm goin' JE's withj 1/2mm overbore, feramic clutch setup, ARP Con. Rod bolts and all the machining to match.