Engine compression for '94 Sunbird

[sunlady]

What should be considered reasonable compression for a '94 Sunbird with a 2.0 liter 4-cylinder engine that has logged over 238,000 miles? My dad and I tested it, and the range was 140 to 165 psi. My brother says it would have been close to 200 psi when new-is this so?

 

[92 Sunbird LE]

Those are great numbers with that many miles on it, the minumium should be nothing less than 100 with no less than 30% difference between cylinders.

200 seems to be too high for a new engine with 9.0 to 1 factory compression ratio.

Is this test done with oil or without oil in the cylinders?

Doug in P.R.

 

[melsg5]

I agree a low compression ratio engine will not generate 200psi

 

[sunlady]

I did not put any oil in the cylinders before the test. Some water squirted out of the spark plug hole on the number 3 cylinder when I first cranked the engine, but surprisingly, that cylinder still showed decent pressure.

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[92 Sunbird LE]

Might want to do a coolant pressure leakdown test to see if the head or its gasket is leaking coolant in the cylinder.

You numbers should come up with a teaspoon of oil in each cylinder if you want to retest.

Doug in P.R.