Nissanfan

I did the compression today, when i was changing the coil pack. Numbers I got:

Dry test

1 160 psi
2 160 psi
3 179 psi
4 180 psi
5 170 psi
6 160 psi

Wet test

1 193 psi
2 200 psi
3 200 psi
4 190 psi
5 190 psi
6 200 psi

I remember searching a while back, shouldn't dry test be 150 across all the cylinders? For wet test rule of thumb, I'm familiar with is 20-30% increase. Is that right?

slorider

I know that consistency is key with these tests. Why is your wet test soo much more consistent between cylinders??

mitsuguy

iTrader: (2)

define dry and wet test...

warm or cold?

fully warmed up compression test "dry" should be from 180-200 given the 10.5:1 compression ratio

add oil (if thats what you mean by "wet" test) and numbers should go up a ton, as yours did, but that is a false reading as the engine oil is sealing the rings much better than when dry... On my GTE pistons / headgasket GE motor, I get 160 across the board... it should be 8.8:1 give or take...

Nissanfan

Yeah engine was warm, when doing the test. Everything's stock, and has 150K miles. Seems like numbers are accurate. I'm convinced the head gasket must be going bad, since I'm blowing a white/grayish smoke, when reving high.

mitsuguy

iTrader: (2)

that sounds more like burning oil than coolant...

what does it smell like?

Nissanfan

Happened just now, rough idle, smell of unburned gas for about a minute. Grayinsh/white smoke. Reved the engine, got back to normal. Happens occasionally, Changed the plugs and wires, coil before. No change. Doesnt seem like a head gasket in that case.

mitsuguy

iTrader: (2)

nope, sounds more like ignitor / coil, etc...

JCkicks300

So on a stock motor what should be the compression ratio ?

saadcee

Spec from the manual:

1,324 kPa (13.5 kgf/cm2, 192 psi) or more
Minimum pressure: 1,079 kPa (11.0 kgf/cm2, 156 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm2, 14 psi) or less

paddy1016

hi all, I'm new in this forum and needing an urgent help. I just baught an used 1mzfe for my es300 year 2002. its been almost 20 days and havent been able to start. at begining we thaught it was an electric problem but today we did compressio test and found out that a cylinder has 100 psi rest were between 100-145. Im in panama and unfortunately there are very few mechanics with experience of these engines. engine is still under warrenty, should I bay it or not????. what is the minimum according to service manual? the guy who sold me the engine, they buy them in US and they dont have any info about them. please help. my whatsapp is +50761302926. ill be so gratefull

2001SolarY

This is the IS300 section for 2001 to 2005. Try posting in the right section for the ES model and year.