im wondering if any one here has done a compression test on the 9 yet, im thinking that the intake cam starting off in the retard postion is affecting the numbers, i did mine last night and its only had 140psi across all cylinders but the car runs fine and has good vacum still, any one else do theres yet?

 

The weird mivec cams might have something to do with the low numbers. The compression ratio is still the same as on the VIII (8.8:1). Also, the gauge you are using could be inaccurate. At least the numbers are consistent, that is the most important thing of all. Try using a different gauge.

 

Ray remember when we did my evo 8 and has 170 + in all cylinders? Well when DTM did a compression check (maybe month later) they got 140 psi all the way across...though the gauge did look diffrent than yours. Peace man.

 

Maybe the new 272 exhaust cam is making the number low?

 

Exhaust cam shouldnt affect static compresion. The intake cam will a bit, which is why race motors, or motors with large IVC volume run slightly less static compression.

Somehow I doubt MIVEC is causing what appears to be a ~15% loss in static compression, but it is possible.. I think the min spec for Evo 8 is 163 psi, all cylinders within 10 psi, if I remember correctly. Someone with a IX service manual should speak up.

Make sure you are doing the compression test right...meaning warm engine, WOT, and make sure the gauge is tight. Sorry if that sounds condescending, but there are plenty of people that dont know how to do a compression check, but try to do it anyway. If you think there is something wrong you can drip a bit of oil in the cylinders. If the compression goes up significantly, you have a ring problem. If you are still low, you might have a valve issue. All this seems unlikely, since they are ALL at 140 or whatever. Usually, when things go wrong, the compression numbers are all over the place for different cylinders.

 

Did they do the compression test while it was hot? Maybe my gauge is just really inaccurate!

 

the test was done right, warm engine, 5 revolutions, throttle open also tried 3 different gauges, all read about 140 to 145 in all cylinders, i think the intake cam is bleeding off a little pressure, i was also told the 9 has a thicker head gasket then then the 8, if anyone has any real facts let me know

 

Why did you even do a compression test? Is there something wrong with the car already?

 

i just did a compression test today 140 across the board with 60k plus miles

 

sry this was on my evo ix