Low Compression On All Cylinders + Excessive White Smoke Out Exhaust

[djaimev]

Hi all

I have a 32 gtr. Driving along and the car lost power, sitting on hwy in 5th gear so i dropped back to fourth put my foot down and revs continued to drop aswell as speed, car bellowed out white smoke from the exhaust,i sh*t myself, turned the car off and rolled to a stop. Car had to be towed home that day (worst day of my life) had only purchased her 1 month and a half before hand. Changed the oil, filter, plugs and flushed the coolant etc when i first got her. And hadnt even done 5k worth of driving but did another oil change etc halfway between. So yeah long story short got her home did a comp test and resulted with low compression along all cylinders ranging between 70psi to 110 roughly, cant remember off the top of my head and leakdown compression rose 30+psi on all cylinders. I dropped the oil, no metal in the sump or anything and nothing milky on cap etc, no oil in coolant as ive checked and ive replaced plugs again, coil packs and CAS.

So obviously getting fuel spark etc as the car starts but on idle the exhaust blows a tiny bit of white smoke, ive noticed some smoke coming from the turbos side of the block but cant see exactly where, so i assume my turbos are gone? And once warm all the vitals seem okay, but when revved the car wont boost, im to scared to drive it incase i make it worse. and ive checked vacuum lines to ensure no leaks but only as much as i could access.

Scratching my head for the past couple weeks thinking where do i start?

My possible thoughts are rings are gone (ive seen many people have had a cylinder down compression or two but not all 6?, um bent valves? I heard could be a possibility, headgasket? And thinking also turbos.

Never been in this situation before so its a learning curve as my old 33gtst was one of the best cars ive ever owned lol. But any info would be great before she goes to pulled apart i guess. Wish money grew on trees though.

Ive spoken to a few mechanics and they are stumped on whats going on? And ive spoken to CRD JEM and Powertune and obviously they cant say anything till they pull her apart which is hard to get there due to living in the gong and work etc. And i dont think theres any trusty mechs in the gong area for rb26s

If i have any luck, someone might of had the same issue and can sort of point me in the right direction.

Thanks to whoever read this far (haha) but more info is better than none i guess and hopefully i can narrow down to how what and why this has happend.

Cheers

[blind_elk]

I'm theorising that you have warped the head, although I could be wrong. I'm predicting that the lowest compression was in #3/#4.

How much water was in the radiator when you finally got it home? When you did the initial coolant change, did you make sure the cooling system was full? via the system bleed valve?

If it is a warped head, you should replace it - DO NOT plane it flat.

[djaimev]

Hey blind_elk, thanks for reading and replying, on the top of my head, i think cylinder 3 was the highest comp at 100-110psi, but i dont have the exact psi readings on me not can remember. When i dropped the oil and coolant when i got it home, levels were fine. Mind you the day before it died i did check the levels also as it was only a weekender so every weekend before i drove her id check. And yes i did. I made sure no airbubbles etc was in the cooling system.

[75coupe]

Get a workshop to comp test it...

Its either rings, gasket or valves

[breaker1845]

You probably don't want to hear it but you need to get your engine out of the car and stripped down to find out what the problem is/was that caused the issue.

I could theorize what your issue is but there is no point as you'd need to get your motor looked at and in good health before you bother to run it again.

Also I suggest never turning your car off while you are actually driving, that is pretty stupid. Could of been your panic reaction though...

[XGTRX]

Sad to hear mate. Just a few things I would suggest before doing anything extreme. Have you checked the your cat isn't blocked. Another is while your exhaust is dropped switch the car on and see if anything is different, like if it smokes and what color it is and give it a bit of a rev and see what happens. Just an idea.

[GTR_JOEY]

Did you compression test the car when you first bought it? If so what psi were the cylinders?

If it were Bent valves you would have heard them hit. Blown rings on all cylinders would blow a shit load of blue smoke I'd imagine. White smoke is generally moisture ie coolant.

Very possibly a badly blown head gasket or a warped head.

Did you car seem to run hot at any stage? The factory gauge works like shit as I found out first hand

If you do a proper leak down test at tdc compression you can figure out where the cylinder is not sealing if you listen for air escaping. Ie intake, exhaust, sump..

If its a blown head gasket you will get bubbles/ airated air in your radiator

[djaimev]

Hi guys sorry for late reply busy lately at work

75coupe, ive compression tested the car with a fully charged battery, fuel pump fuse out, full throttle and about 6 cranks, thats the right way yeah?

Breaker1845 - yeah i guessed that would have to be the plan. Just getting it somewhere isnt the easiest lol and i havent started her since and yes at the time, i freaked and furst instinct was to stop her before she did more damage

XGTRX - havent checked anything exhaust wise as my garage is failry small with no room to move much and my driveway is on a slant so i cant get anything from underneath but i will try cos i e heard bits of the turbine may end up there (ill be spewing if thats the case too, cus ive just got turbo back exhaust system with a hi flowed cat but ill give it a go.

GTRJOEY - tbh mate i didnt i shot my self in the leg when i bought because mechanically and visually there was nothing i could find. I checked for coolant leaks oil leaks checked the oil coolant, rust, afms all lines and etc and couldnt find one fault.and drove like a dream. Except about a 2 3 weeks after buying top rad hose split replaced and good as gold. Yes i have heard the sound of bent valves on a skyline and nohlthing sounds out of the ordinary. It is not an excess amount of white smoke on idle but when it drove it was bad. Couldnt see anyone behind me. I did have one problem with the gauge about 4 weeks after buying but when i took the cluster out, a line on the back had all been burnt around it (if that makes sense) so i got the back cleaned up and never really went past the usual mark again... so yeah :-/

[GH05T]

did a comp test and resulted with low compression along all cylinders ranging between 70psi to 110 roughly, cant remember off the top of my head and leakdown compression rose 30+psi on all cylinders.

im assuming by "leakdown test" you mean a wet compression test? i.e bit of oil in the cylinder then retested?

if your results went up that much it is more than likely poor ring-bore sealing.

afaik

a head gasket issue usually gives you banana readings, low on one end or on adjacent cylinders, obviously due to being warped.

bent valves usually shows on the one cylinder you bent it on... i would imagine bending all of them is possible but yeah you would have heard that. plus it would be the result of a timing belt gone walkabouts so you would know.

but like everything all 6 rings worn is no better as its just as big of an issue.

what colour is the smoke, blue? pillow white is an unusual symptom if your coolants fine, and turbo issues wouldn't do anything to compression.

Edited April 15, 2015 by GH05T

[MozzMann]

im assuming by "leakdown test" you mean a wet compression test? i.e bit of oil in the cylinder then retested?

No , well not quite but close.

A " Leak Down " test is done with an Air Compressor and a special tool that I have below. This measures the relationship of the Air in v the Air out, and gives you the leakage past the rings for instance as a percentage.
It can also help find and diagnose possible Head Gasket and other internal leaks in an engine.

Usually a Operating temp test is done and then add some motor oil to the cylinder and repeat noting the percentage (usually significantly lower with oil) then the car is run to burn off any oil in the cylinders and then a compression test is done. First dry and then with Oil noting the Pressures before and after.

Snapon Leak-down Tester above .

SnapOn Cylinder Pressure Tester .

I hope this helps clarify

Ideally most engines (Petrol) I would consider 120 -180 PSI a good ball park figure. This of course depends greatly on the age and type of engine being tested.
Wet pressures can be as high as 250 PSI perhaps and usually even across the number of cylinder's your checking , if you find one or more that are virtually no rise in pressure with oil present then you have found the issue.
It could be something as simple as the need for a Bore Hone and new Pistons and rings to suit .

I hope this helps .

Edited April 15, 2015 by MozzMann

[djaimev]

Not much of an update on my findings as of yet guys. And still saving for crunch of rebuild

Replaced the battery and rechecked compression

Car wasnt warm on the test incase that matters

1st cylinder is now at 130-140psi

2nd is also on 130-140psi

And 3rd is also on 130-140psi

4th is at 75-85psi

5th is at 80-90psi

And 6th is at 110-120psi

In the process of taking the turbos out (a big fun job)

I noticed the rear turbo had abit of oil around pipe once i took the intercooler pipe piece off and the rear housing of turbo on exhaust side. (Reason why im taking them out) im getting a sort of popping noise from around that area also...

So im thinking to add to the list, turbo seals gone?? Cos surely that would not have caused the low compression?

Ive checked the cat and seems fine, nothing out of the ordinary nor collapsed or anything.

[MozzMann]

The seals are likely the cause of the smoke with oil ingress into the inlet . Is the inside of the inlet piping and manifold oily ? The turbo's can indirectly be responsible for the low compression due to high cylinder pressures in certain cylinder's wearing some rings more than other's but you have relatively even pressures except for 4 and 5 which leads me to think that you may have some excessive wear in those cylinders compared to the other's .

You could possibly get away with a new set of rings and a hone, BUT you need to strip the motor to do that so you may as well go the next oversize pistons as long as the motor hasn't been bored over size already. If it has you might need to check the maximum allowed oversize for that engine.

New Pistons & rings to start with and if you are stripping the motor I'd be checking Rod and Main bearings for eccentricity and size and if needed rebuild the whole thing. Preventative maintenance I'm afraid.

Edited July 1, 2015 by MozzMann

[Ben C34]

Head gasket between 4 and 5 is my vote.

[Hadouken]

Agreed. Head gasket.

[MozzMann]

Good point fellas , pressure bleeding between the cylinder's at a point where it doesn't impinge on the water ports.
bit hard to say until the head is off of course.

[Hadouken]

My first thing with those readings would have been to pull the head off.

[Ben C34]

I'd pull off. Then decide what next.

[djaimev]

Thanks for the input guys. Went to a local shop thats got a decent rep down my way with imports. Spoke to them about it. And getting diagnosed in the next week or so when i have time to tow it there.

And yeah id love to take the head off but half the shit in the 32 manual is like rocket science to me. Ive exposed the turbos (easy part) and then due to lack of the right tools i got stuck. Interesting to see what they find as ive dropped the coolant and no oil at all. Checked the intercooler also and dropped the oil too. Hadnt started it in a while, vitals seemed fine just didnt feel right, idle was bad (wish i could show a video) took the oil cap off for the 3rd time to see and first time i seen it was a bit milky but wasnt sure as ive had that same issue on past cars that hadnt been started in a while

[Ben C34]

Many, many times a head gasket will pop and not break into an oil area. So the lack of milky oil means basically nothing. No way 2 side by side cylinders just happened to wear out for some reason. I would put money on the gasket. Cash money.

[djaimev]

Sweet dude. Thanks everyone for their inputs. Gets diagnosed soon. And as soon as they find out what it is. Ill post up here for any future issues anyone else may have.