Page 1 of 1
Compression test results
Posted: Fri Sep 12, 2008 2:55 pm
by jeepstertim
Concerned about a lack of power in my 3.9 EFI defender i carried out a compression test yesterday and got reasdings from 130 - 140 across all cylinders which seem a bit down on what i was expecting.
While testing i also forgot to have the throttle full open, will this have affected my figures by much?
Posted: Fri Sep 12, 2008 4:35 pm
by katanaman
It might have done but I dont think your figures are too bad anyway. They are all pretty close to each other so nothing major is happening.
Re: Compression test results
Posted: Sun Sep 14, 2008 9:53 am
by jefferybond
jeepstertim wrote:While testing i also forgot to have the throttle full open, will this have affected my figures by much?
yes i believe that will make a difference.
jeff
Posted: Sun Sep 14, 2008 8:12 pm
by jeepstertim
Which way is it likely to affect them, I am hoping they would be lower if the cylinder wasn't breathing so well - but by how much?
Posted: Sun Sep 14, 2008 10:31 pm
by katanaman
if you did the test properly and turned the engine until the gauge stopped rising then there is no real difference throttle open or closed. I think the fact they are so close together means your testing was ok. Compression test isnt really the best as so many things can effect the result with ultimate reading. Leak down test is the ultimate but you need a compressor and a couple of other bits of kit to do that.