Quote:
Originally Posted by jwakil
I don't understand how a car could be running well with one cylinder at 80% leakage (not 80% good, but 80% bad). And my thinking right now is if I have a engine rebuild in my future anyway, why not keep driving it until it start running horribly. I will do another leak down test soon. Haven't had access to the tool.
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80% leak down does seem high to have no noticeable running issues, but perhaps the engine is still developing enough compression on that cylinder. There could be an accuracy issue on the guage of the leakdown tester you used. You can do a compression test and see how #1 compares to the other cylinders. Likely it is down vs. the others (corroborating your leak down test), but still manages to develop some compression.
In the photo series I posted above, my cylinder with 44% leak down had lower compression than the other cylinders. I don't recall the exact numbers, but 5 were at 135-140, and the offending cylinder was at 125 or so. Plenty of compression to run, and run well. What is really surprising is that pistons with completely shattered rings showed excellent compression and leaks own numbers. The ring bits were all captive in the ring lands, of course.
My car ran very well, no smoke at start up or on boost. Ignorance is bliss, they say. Had I not done any tests, I might still be driving it with these issues. I was motivated to run tests when my car with aftermarket headers and a K27 turbo could not outrun a stock example
