Compression Test Results

[GTROID]

Few weeks after installing new turbo i had lots of white smoke when lifting off after heavy acceleration, had parked car up for a few weeks before looking at the problem, smoke was more evident this time around, really bad after a good hit on boost, when pulling up at home it was puffing smoke out exhaust on idle, so i've done a compression test.

Did test cold as im not that keen on driving the car to warm it up, for wet test i added 3ml of oil. All with open throttle.

cyl 1 cyl2 cyl3 cyl4 cyl5 cyl6

dry 136 dry 125 dry 125 dry 125 dry 130 dry 40

wet 144 wet 134 wet 137 wet 133 wet 143 wet 48

Does this indicate valve seal? Is there any further tests i should do?

If it is the valve seal is it fine to fix the issue and refit the head or should i pull the motor out and have it inspected?

Appreciate some feedback, thanks guys

[MrStabby]

Could be head gasket. Check for bubbles in the coolant when the engine is running.

[GTROID]

No bubbles, sorry forgot to mention that i had checked that.

[rb2534]

I would be looking more to valve seat, valve itself and possibly the valve guide. A leaky valve stem seal would give you oil in the combustion chamber which you said you have and you should technically still have compression in the cylinder.

If the valve head had dropped off you would have heard it rattling around inside your cylinder or even worse in the back of your turbocharger and if the valve was jammed wide open or the valve head missing the comp would either be zero regardless of a wet or dry test.

I had an engine at work with 15psi in a comp test and it ended up been a torched valve face but this was on a large industrial gas engine running around 700degree exhaust temps so torched valves and recessed seats are pretty common hence why we change heads out every 20,000 hours whether they need it or not.

Perhaps pull the rocker cover and see if any of the valve springs are excessively loose or if any of the valve heights are different as they should be relatively close to one another. That will either give you and indication of a recessed valve seat causing it not to seal 100% and if a valve is missing the head the valve spring will be sitting higher than the rest of them and the spring will be loose and very easy to turn.

At the end of the day the head will be coming off regardless but if all looks good there you could be looking at a piston

[XKLABA]

Sounds like what my 32 did, was broken ring land

[GTROID]

Ok thanks for replys, appreciate it.

Will check what you said rb but looks like all those numbers are fairly low to other results im seeing online.

[Ben C34]

They are cold numbers though. warm it up and do it again. Smoking a bit won't kill the engine.

[533 RYC]

Sorry, off topic, but, Giulian I might know you. EFX??

[533 RYC]

You will need to remove cams to check spring heights correctly. Recessed/leaking valves will give low comp readings wet/dry hot or cold. A torched valve will give the closest to zero reading, providing the rings/lands are in good nick.

Either way the head has to come off & checked before you decide to pull the whole lot out as #6 is f%#ked.

Question 1: Why was the turbo replaced?

Question 2: How many K's has your engine done?

You state its white smoke coming from the exhaust. Does it smell sweetish like glycol/coolant?

Have you had any coolant loss?

If you run over 12-14psi, have you done a head stud conversion?

[GTROID]

Had a boost leak and when trying to find that i had checked the turbo which had massive amount of shaft play, so it was replaced, running 14 psi and have not done head stud conversion.

Motor has bout 150 on it.

It has a bit of a smell but isn't a coolant smell i don't think? will check that, coolant is clean and oil is normal looking, no milkyness.

No coolant loss, lots of oil in all the cooler piping etc which i expected to see.

According to receipts in the glove box from previous owner 'Sensor drive gear in camshaft worn causing erratic timing control. Removed cam sensor, clean area where gear and spline connect. Under customer instruction fixed sensor drive to camshaft with devcon.'

I don't fully understand as i havn't seen the setup for that but that seems dodgey as f... to me? Wouldn't you just replace the CAS?

[Ben C34]

The actual drive in the cam wears out so replacing the cas won't fix it. Only way to fully fix it is new cam .

Did you clean out all the pipework and intercooler of the oil from dud turbo?

Edited January 30, 2014 by superben

[GTROID]

Ok thanks could that be likely to cause valve issues long term?

Yeh cleaned all that out, will probably pull motor out, after talking to a few people it sounds like its at that age for a rebuild anyway, thanks all.

[533 RYC]

Devcon is bog for metal. We use it sometimes on lower liner fits when they pit & leak on engines in the field. It's not to bad a temoprary fix when the customer doesn't want to blow a million bucks (literaly-I'm not joking)! A set of cams in an RB on the other hand, you'd get away with poncams, sprockets & a tune for around the $2k mark.