80tq: Head Gasket Failure

[JShadzi at aol.com]

After recent discussions and the fact that my wife was out of town for the weekend I decided to tackle the head gasket since it was becoming more and more obvious that it was a problem.

Thanks to Christian Miller for the use of his Dad's shop and helping turn wrenches, it was a nice, enjoyable job, we took a leisure pace and took our time.  Work began Sat morning around 11am, by 12:30 or so the head was off and we took a lunch brake, after lunch the head surface and block were cleaned up, studs installed, new gasket, etc, and oh, noticed this:

http://www.80tq.com/images/HG_failA.JPG

and

http://www.80tq.com/images/HG_failB.JPG

These pics are pretty consistent with the way the gasket looked, very beat up and worn.  Definitive leaks in #4 and 5, suspect in #2 also though its a surprise any of the cylinder held pressure including 4 and 5.  #5 header runner had evidence of leakage in as the runner looked like new inside.  This gasket only really leaked under heavy boost conditions consistently for a year, never a big blow out like you'd suspect with a HG failure.  The stock bolts had varying torque on them, some were much looser than others, in the future I'll be using only studs on motors with more than stock specs in mind.

We quit early on Sat around 5:30, Sunday morning we spend an hour or 2 buttoning up the front end and cleaning up the shop, car started right up and has been running like a top.

Pistons and comb. chambers looked great, not a pit in sight.  These motors continue to amaze me with durability, this motor has about 40k hard miles since I put it together, it held up really well considering 034efi development, about 30 track days, ignition development (read detonation), cooling system development (read overheating), etc.  I figure the motor was due for a HG.

I'm in the process of putting in a Crane HI6 capacitive discharge ignition and race coil, I'll post results of how that helps, from some research i've been doing it appears that many cars greatly benefit from similar CD systems, so I'm hoping this will help my problem too.

I plan on doing a few track days next month so I'll post results on whether i've made any progress on the cut out problem.

Javad
80tq.com