Compression Test Results

[bmohan55]

An easy way I was shown to check for leaky valves is with the head off, tilt it on it's side and pour a little bit of automatic transmission fluid down each plug hole. Watch to see which valves leak the fluid out.

[Sputnicker]

I took another look at your photos and now I think I can see evidence of the gasket leaking between 2 and 3. Chances are that a re-surfaced or new head will eliminate the problem, but you might want to check the top of the block with a straight edge and feeler gauges just to be sure its also flat. These failures are not generally caused by a faulty gasket, but rather a problem with one of the surfaces and/or improper torquing. Look closely for cracks while you're at it.

Also, even if you decide on a new 8:1 head, it might be informative to disassemble the old head to validate the diagnosis. If there are burnt valves you may have a mixture problem that needs attention.

Good luck.

[willincalgary]

Conditional Success

Over the past couple of afternoons I installed a newly rebuilt 8:1 head. I haven't run a compression test with the new head (ran out of time/energy tonight) but it appears to be idling much better and anecdotally it seemed to have better torque while moving from the garage to its parking spot. I haven't given it the full stress test yet and let it rip on a roadway. Any break-in period? The exhaust is now puffing continually outward, which is a distinct improvement. I must not have gotten a tappet adjustment quite right as it has a distinct tick but that's minor.
I'll post an update after I've run the compression test later this week.

[Nium]

After 500 miles it would be a good idea to re-torque the head bolts. Glad it's runnin better for you without you having to do the bottom end.

I guess it was just the blown head gasket after all. Will be interesting to see what compression results you get now and if it still overheats.