compression result how bad is this???

[M-type]

Compressions are #1 120PSI; #2 125PSI; #3 135PSI; #4 125PSI; #5 140PSI; #6 130PSI

[nelsonmxmarc]

Not good.

Compression is a bit of a shady topic because it leads to so many sub-categories of issues and possible causes..

The obvious ones are ring wear and are the most common for a stock motor/build as it's not subject to high boost, meaning the headgasket should still be in top shape.

The other can be as i just said, the head gasket. If it's leaking, you'll be running through a bit of coolant that's escaping the galleries and will notice it going down / puffing white smoke is also a good indicator. (At this temp it will be hard to tell, but smell the moisture at the tip, it will smell like burnt coolant)

Lastly you'll be looking valve seats. If the valves are nice and dirty, it could be they're sticking open a bit allowing air to escape. This isn't THAT common but still viable as an excuse for low compression.
There are a few 'cleaning' additives/machines like Motorvac that clear out gunk, but on old used up valves/guides/seats, it could cause more harm than none if the debris is severe.

In this case, your best bet would be to have a leak down test. Now correct me if i'm wrong because i've yet to do one, but it will discount the data of the rings, and pinpoint head and valve seep, whereas a typical compression test that monitors compression on each bore will account for ring wear however discounting hg and valves (although these will have an affect). Basic hypothesis here is that the normal-standard issue compression test doesnt discount much, it gives you a number.

[cobrAA]

did you do this test in a nissan dealer?

[M-type]

yep thats right leak down it is

[M-type]

did you do this test in a nissan dealer?

yes welland

[M-type]

I was thinking it was little low and all over
120 psi on #1cyl in a skyline I knew couldnt be right
#5 seems to be the only cyl with decent pressure

[cobrAA]

yes welland

a friend of mine wrote on his wall ( facebook) that there was a nice impul 4door ar her job LOLL I'm sure it was you.

[MattRose]

I have a stock R33 with 60,000 kms and my compression test ran 150, 151, 150, 149, 150, 151.

[Oakville]

yeah cobraa it was rena haha

[M-type]

a friend of mine wrote on his wall ( facebook) that there was a nice impul 4door ar her job LOLL I'm sure it was you.

yes indeedy it is

[CelicaKidd_205]

She said the car had some overheating issues. Do you see any white smoke when you fire it up. It is normal at this time of year to have the translucent steam from the tailpipe, but white smoke will indicate burning coolant, i.e. head gasket. Another way to tell the difference is the exhaust fumes should smell very sweet, almost like a sour candy kind of smell.

[nelsonmxmarc]

Another thing to account for is variance between compression on each cylinder; rule of thumb is, anything within ~15% variance is acceptable, above that, there are going to be issues and the top end should be replaced without question..

15% of your highest value is 21. Meaning, 140-21 is 119 - close to your lowest reading of 120. This would deem your top end due for maintenance.

[fast316]

Now correct me if i'm wrong because i've yet to do one, but it will discount the data of the rings, and pinpoint head and valve seep, whereas a typical compression test that monitors compression on each bore will account for ring wear however discounting hg and valves (although these will have an affect). Basic hypothesis here is that the normal-standard issue compression test doesnt discount much, it gives you a number.

Cylinder leakage test will tell you where the leak is coming from, past the rings, intake or exhaust valves, or head gasket, and how much of a leak. They require a few more tools, but if you can do a compression test, you can do a leakage test.

[M-type]

THANKS EVERYONE FOR FAST REPLYS
condensation vapors do look a little thicker then norm but smells rich not sweet
and at operating temps no vapor
after converting to bar
minn spec. 9-3/4bar max 12-3/4 bar

1-8-1/4
2-8-1/2
3-9-1/4
4-8-1/2
5-9-3/4
6-9-0/0

variance allowed 1 bar across all and reading is lowest 8-1/4 highest 9-3/4 so 1.5 bar variance

cyl 5 is really 9.65bar annd min is 9.75bar so really all are below spec...
min avg would be 9.75 .. my avg is 8.87

**** any way you look at it

[M-type]

taking firing order into consideration

1 --- 5 -- 3 -- 6 -- 2 -- 4
120-140-135-130-125-125

1,2,4, - worn ring and seals?with 1 being worst
5,3,6 - rings?
but i dont know if they recorded front to back back to front or firing order
but if by cylinder number then there you go