Bad compression Test, What now???


I did a spark plug change a few weeks back, and saw some more oil on the plugs than i wanted. Tonight I did a compression test, and got 208, 208, 150, 158/160. I’m pissed. I have JDM b16sir2. I had one oil change that was dyno oil througout my usual synthetic oil changes. I"ve only put 12,000mi on the motor. There are NO signs of blue/white smoke, coolant in oil/oil in coolant, its not eating oil nor eating coolant. Please help me. I’m hoping its just teh sign of a head gasket going or some piston rigns cuz I really dont want to have to Re-do the Valve seals. Thanks,


do a leakdown test to see exactly where the lost volume is going

I mean’t to add that I put 12,000mi on the motor, but in addition to what ever was already on it from Japan.

and whats the best way to get a leak down test if I dont have the equiptment?

When you did the compression test, did you try squirting a little bit of engine oil into the cylinders after the first test, then retesting? When you do that, if the compression goes up then it’s your rings… if it doesn’t, it’s the head gasket or something in the valvetrain.

OK heres an update:

Tonight I, ran seafoam through the vacuum line. Got it out of the system. Proceeded with a second compression test. On the first cylinder, it read 150psi :wtf: 2 nights ago it was 208 psi. I moved on to the rest of the cylinders adn ALL read between 150 psi and 180 psi. So, this means that cylinders 1 & 2 went down from ~210 psi to ~160 psi in 2 nights… what the hell. I then ran oil through all the cylinders and did a test and all cylinders showed at least a 20 psi increase, and one as much as a 90 psi increase (240psi). I have no idea if this spells a bad compression tester!!! OR… is my WHOLE MOTOR FUCKED???

I still dont blow any smoke and generally the car drives AMAZINGLY if I’m really 60 psi low in all 4 cylinders… I"m super confused…

maybe u did the test wrong…either way…go to someplace that does leak down tests…or to just test the head…take the head off…pour water down each exhaust and intake port and see if any water leaks out of the valves…if so…new valves or valve job!!

yeah i’d have a leakdown done. but when doing compression, make sure to take out all plugs, and do the test with the gas to the floor. hth

How much oil did you put in? Even if the motor was brand new, you shouldn’t be getting 240psi. It does sound like the rings are shot though.

For what it’s worth, I drove my old Civic with a blown head gasket and a warped rod for over a year - compression was something like 90/150/160/80. It had absolutely NO power below about 4000 rpm, but it still pulled damn nice once you wound it up… (but anyone behind me was stuck in a smokescreen from all the oil and coolant… lost about a quart of oil a week with no leaks)

are you screwing in the tester snug? are you doing it with the motor warmed up at operating temp?

how many times are you cranking it?

I was only putting in about a half capful of oil, no more than 3/4 of a cap. Tester was snug. up to temp and everything. The throttle was not open, which is what I"ll try next, but all successful tests i’ve done in the past did not require that. I should note that on the end of the tester, there is the standard spark plug style metal ring, and between it and the metal threading is a rubber o-ring that is shot to hell. I get mixed feelings on that from people. many thing it should seal in the threads.

I’ve alwaysed noticed oil on the little head gasket “tab” that sticks out left of the exhaust header, and also my header gasket must have a leak cuz its always dark and oily/sooty behind it… not sure if the head gasket is contributing… seems to me head gasket would show more signs…

would there be a point to re-torquing the head bolts?

head bolts shouldnt come loose. but you could try :think: