Compression numbers, I need your input

[Jaino40]

123 150 139 145

Are these horrible?Would it be safe to mod this motor?I unplugged injectors and cam sensor when I did this.

Thanks

[Jaino40]

And throttle wasnt at WOT, would that have made a difference?

[needmorenissan]

was it warmed up the engine? when its warmed it gets better numbers and ya that is pretty bad stock is 180 so u should probaly do a rebuild or something

[Jaino40]

Really?I did a google search and saw ALOT of 150's.I figured, maybe the 123 was maybe on the edge. and considering maybe if the wot does make a difference you know...

Any other input?

[turtle240]

Standard is 179 psiMinimum is 151 psiWith max difference of 14psi

so unless thee engine wasnt warmed up enough then you might have valves, rings, or a blown head gasket and since the head is aluminum if you did blow a head gasket you might need to machine the head b/c of worpage

anyway i would seriously do a rebuild

[Cone Junky]

123psi is definitely too low. The fact that there is such a deviation between cylinders is also a problem. The difference is right at the margin of a bad engine (20%). The engine will never be able to run properly because it will constantly try to compensate for the weak cylinder.

It may be good enough to drive, but a waste to modify. A fresh engine will give more power gains than any bolt on modification.

[KATizzle]

You have to do it at wide open throttle to get correct readings. Do it over again. My numbers were 125 150 150 150 without pushing the throttle. I re did it and got 170 175 173 174.

[1990-240sxsr20det]

IF you're getting odd numbers still even as your redoing the test WOT, then i would definitely check out our compression rings, head gasket, etc etc..basically rebuild it you should be golden

[grecco28]

if you get 170 on hot engine and full throtle is ok... the 5psi diference is ok..my ka have 150psi even on the stock engine with 250k miles almost... and still run strong.. the idle is very steady to...