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"After engine repairs, I found cranking compression tests to be around 70-80 psi. That's what you get with a 6.45 comp ratio. I assume psi will go up a little after seating the new rings."

Thanks for the post. When I checked compresion in mine, the most I got was around 60 psi with my compression gage (which I am not sure it is correct but I will check some day with another one), and that was pretty even on all cilinders except for cil no 1, with cero, and cil no 3, with around 40. I will start using the car and check again some time in the future, hoping that the detergent oil plus seating of everything inside, will make it rise to 70-80 psi... but I have say that even with the 60 psi I am getting and the engine running like it is now, I am very impressed of it's smoothness and power.

Victor

One interesting piece of information I never mentioned which apparently can explain my "low" compression reading.

I live in a city which is about 1.2 miles high. According to my mechanic, he has done tests at this altitude and also at sea level, and the pressure up here can be around 10 - 15 psi lower... that is, my 60 psi reading could be between 70 - 75 psi at sea level. I don't know how correct and accurate that is, but it surely makes me feel better to know it.

Thanks,
Victor

Altitude definitely changes compression pressure. My shop is only a few hundred feet above sea level.
If you have less air (lower barometric pressure) to start with, then your final compressed pressure is going to be lower. Your 60 psi sounds healthy enough, but you will be down on power vs. sea level.

There is a 3% loss of efficiency for every 1,000 feet above sea level. The loss would be almost 20% at 1.2 miles. I used to live in Santa Fe, NM and at 7,200 feet altitude, we figured at least a 21% loss as compared to sea level.

(o{I}o)

ineffabill and JW:

Thanks! Your posts make me feel better, seeing that my 60 psi is about what my engine at this altitude should have or just a tad low. I have been using the car for a couple of days now and will continue to do so for a few weeks, and then I will check on compression and everything again. I will let you know my findings.