very odd compression results... [Archive] - SR20 Forum

: very odd compression results...


NismoSER
04-13-2002, 07:05 PM
Well, I was working with the NX2K today, prepping it for the motor swap in a few weeks. I finally got my paws on a compression tester and took it to good use.

Results:
cylinder1- 190
cylinder2- 210
3 - 190
4 - 185

Whoa! That's what I said. I took it to my SE-R just to make sure the guage wasn't wacky and I got low 170's psi across the board. It wasn't the guage.

If a car is supposed to have a blown head gasket, isn't the compression supposed to be lower?? Something must be causing this car to run crappy.

I started draining all that excess oil out....FOUR quarts came out before the oil level was back into spec. Unbelievable!!! I took it out for a spin then, it got a little power back, but did not feel like your average SR20 motor. (the car looked funny driving around without a hood :))

I figured since I was getting a new motor no matter what, we should explore the rest of the motor. We pulled the VC cover off, and the cams looked great...nice and smooth. Not bad for 163,000 miles. Everything under there looked good, and the timing chain looked pristine.

We started dismantling the car, removing the intake stuff, EGR, AIV, radiator, and started working on that blasted exhaust manifold. We got all of the nuts off of the studs without breaking any...nice clean releases. The biggest problem was getting the manifold off of the downpipe and the EGR off of those. >:(

The manifold is still on the car, because we couldn't get the manifold off of any of the studs and we were too tired to do anything else.

I should have thought of it before, I should have checked the compression with all that oil drained out...it probably would have been back to at least below spec.

I found the coolant leak to be coming from the front cover side of the engine, right above where the oil pan attaches to the block. The oil I drained out was clean...just a little darker than usual, but not tan or milky. The coolant was still at a decent level, and was a bright green...just like new.

Actually, maybe right now I'll go pull some compression numbers with the right amount of oil...sorry for the long thread! any input is appreciated. :)


EDIT: I rechecked the compression....same results...

eric96ser
04-13-2002, 11:02 PM
Having a lot of carbon depsoits on the pistons would cause this, or by having the intake cam retarded would also cause this.

NismoSER
04-14-2002, 12:57 AM
would having either of those make the car run very poorly? The only reason I thought it was odd was because the woman I bought the car from said her mechanic told her that the car had a blown head gasket. I was expecting to see results completely opposite from what I found.

when you say just the intake cam is retarded, would that be implying that that the timing chain may have jumped a tooth?