4AGZE Compression rate

[Ben Wilson]

I'm not sure, I know I hit the rev limiter within 5 minutes of getting my car driving

[inertia]

I have a GZE but never done a test and not even driving it yet ... should finish building up end of this month and I'll run a test on it as well ... Hey, not so sure about this but you said you recently installed the GZE??? I was told by few fellows on the forum that after the engine swap or etc you should drive normally without reving the sh!t out of the motor for like 5000km or so??? ... again not so sure about this but that is what I am going to do ... Could that be a problem??? ... someone please advice

That'd be for a rebuilt engine to let it settle/adjust/wear in.

[inertia]

Craigy,

There's a ton of part numbers depending on oversize, or mark 1,2,3 (whatever that means.)

Anyway;
Late model AE92: 13101-16130-(01 or 02 or 03) or 13101-16131-(01 or 02 or 03)
Oversize .50: 13103-16130 or 13103-16131

AE101 GZE is 13101-16131-(01 or 02 or 03)
Oversize .50: 13103-16131 or 13103-16131

[30psi 4agte]

do you still use the pcv valve ?? could be gunked open and causing the engine to suck down oil.

What sort of breather setup do you have ??

[SLO-055]

you'd find that with seals gone on a turbo it'll blow smoke while idleing to, which i didn't see you had written down, as for the comp test, you doin it with the throttle wide open???
my gze read exactly the same on all cyl as yours does, and uses no oil, so i'd be pointing somewhere other than cyl damage, especially as it's only a 20psi variation.
you sure all your breather hoses and equip are installed correctly, oil return for turbo is feeding into sump above oil line, just that sorta stuff.

[inertia]

It's not turbo "bro"

[craigy]

Thanks everyone for your reply's, i've cut and pasted your questions and written answers below:


How good is your compression gauge? I'd be less concerned about the actual readings, and only worry about the variation between cylinders, unless you trust the calibration of your gauge 100%.

My compression gauge is brand new, i havent had a chance to calibrate it correctly but as you say, the difference between cylinders should be the main concern.

The smoke white or grey under load?

Smoke is white/grey colour, its a little hard to tell whilst driving the car

much smoke on first start up of the morning?stem seals would be hard pressed using two litres of oil in a week.

Its blowing minimal amounts of smoke on startup, it really doesnt compare to the amount it blows under load

cant hear and rattle noise from cylinders?

There doesnt appear to be any unusual rattles coming from the engine bay. The car is pretty loud as it is, so its quite hard to hear small rattles etc.

was the plug from No3 oiled up?

I was dumb, i pulled all the plugs out without taking note of cylinder. I'll do another check tomorrow after a couple of days driving.

your dipstick being pushed up after driving?

Dipstick is staying in place.

is there much blowbly out of the dipstick tube when free reved?

Yes, oil is splasing up the dipstick after a drive.

When doing a compression test if you haven't disconnected your fuel pump will the fuel increase compression that has been fired into the cylinders?

I locked out my ECU whilst testing compression and dis-allowed fuel and spark.


Also are you sure its oil smoke that you are blowing on boost? That map pours out plenty of chuff when you plant the foot, especially if the changes for the bigger injectors have been made conservatively.

This chuff you speak of Hen, i assume you are talking excess fuel? Should be black smoke, yeah?
Also remember I'm running the larger pulley (thanks to you), running 12-14 psi so its probably burning the excess fuel.

Do you still use the pcv valve ?? could be gunked open and causing the engine to suck down oil.

PCV valve? I should know what that is....assuming something to do with vacuum/ crank venting system

What sort of breather setup do you have ??

I'm using a small catch can, fed from the rocker cover through the can and back into the intake (have run disconnected to check for blockages)

[sr20 trueno]

How good is your compression gauge? I'd be less concerned about the actual readings, and only worry about the variation between cylinders, unless you trust the calibration of your gauge 100%.

Thats what i was told... you should be more concerned with the evenness of the readings.
Maybe you should get a leak-down test... if its done by a good operator it will show exactly which part of the engine is causing any loss of compression...
a stock engine with standard pistons and rings shouldnt show more than 8-10% leakage unless there is a problem

cheers
Daniel

[inertia]

Craigy, you wanna test the compression on my MAP gze and compare?

[Ben Wilson]

I'm using a small catch can, fed from the rocker cover through the can and back into the intake (have run disconnected to check for blockages)

You are running it back to the original (pre throttle body) position I assume?

[The Witzl]

You are running it back to the original (pre throttle body) position I assume?

I hope so! Otherwise he may be pressurising the crankcase

... and sorry about thinking this was a turbo engine, i dont know where i picked that up from.

[Kebin]

i just bought a gze and thought i would compression test it before doing anythin else.
I checked my compression using a new compression gauge and it comes up as follows:

cylinder 1: 200psi

cylinder 2: 210psi

cylinder 3: 195psi

cylinder 4: 210psi

The engine is an ae92 afm with dli
Will these readings be suffice or would i be heading into problems further down the track?
I dont entirely trust the accuracy of the gauge either....