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Compression Test Results
Posted 16 December 2006 - 11:55 AM
Cyl 1 - 100
Cyl 2 - 105
Cyl 3 - 95
Cyl 4 - 105
What do these results show me? Should I do a wet test now as well?
Also, I didn't do this with the engine warm. I've heard I need to do it with the engine warm, and I've heard I don't. Is the engine supposed to be warm?
Posted 16 December 2006 - 12:44 PM
I have always done it cold on an aluminum engine, as you dont want to mess with plugs on a hot engine (can damage threads). Also do it with the throttle wide open, and a fully charged battery (or a jump from a running car).
Posted 16 December 2006 - 01:29 PM
According to my FSM that is at lower limits. I would do a wet test and report back.
Also remember that engine sat for a few years so I would also run some seafoam/oil treatment through it and give it some miles...did have a possible 180k on it though. How did the cylinder walls look when you had it apart?
Oh and here is a link to the 2 pages from the FSM about compression testing:
Posted 16 December 2006 - 05:16 PM
Posted 16 December 2006 - 11:27 PM
If so, and I assume there is, anybody want to take an educated guess?
For instance, when a car is new, the compression number is probably around x, and the mpg is usually y,
When a car 10 years old with 150,000 milies on it, the compression number is probably going to be around x, and the mpg is usually y...
When a car is 20 years old, with 250,000 miles on it, the compression number is probably around x, and the mpg is usually around y....
Posted 16 December 2006 - 11:31 PM
But yeah, milage would decrease if compression decreased. The higher compression the engine has, the more efficient it is. The lower the efficiency, the lower the gas milage.
Posted 16 December 2006 - 11:41 PM
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