rings or head?

[birdy3897]

I have an older 2.5L and my compression is 125-130 in all but the number 4 cylinder which is reading 95. How would I test to see if it is the valves or rings?? Would a leakdown test tell the tale? Also, is 125-130 ok for compression readings? The boat runs decent, but won't idle really smoothly, but power seems ok.

 

[Cptkid570]

Re: rings or head?

You could do a wet test (put some oil in the cylinder before doing the compression test). In theory, the oil will help seal the rings. So, if compression goes up with the oil in the cylinder, then it may be rings. If compression stays the same with the oil in there, then it could be a valve.<br /><br />Do a search for wet test and you'll probably find more info.

 

[Haut Medoc]

Re: rings or head?

Leak down test...Look in the search function on how to perform this....95# is low, but not dead yet.... Pour a little oil in the low cylinder, if the # number rises quite a bit, most likely rings......Testing with a vacuum guage will shed some light also, with valve train issues.....JK

 

[birdy3897]

Re: rings or head?

thanks