Surfer90291

Since I bought this Z I've noticed it's been quite hard on oil, about 1 qt per 1000.
It's a 04 6 speed non-rev up with 111k miles.
It has been a pleasure to drive, seemed like all the maintenance had been followed (noted valve cover gaskets) and doesn't smoke on startup. Car isn't leaking, the exhaust tips / rear bumper gets dirty faster so I assume the oil is being burnt. Replacing the pcv didn't do. I wonder whether it's rings or v. stem seals or else..

Anyone with common symptoms fixed this consumption?

i-break-things

Very common issue with these motors. Search for catch cans and engine vents. Adding a catch can will prevent from passing thru the engine.
The cause is crank case pressure. Add in the fact the engine has piston oilers and the air attempting to leave the engine can carry a good bit of oil.
A catch can is the first best defense. If you forced induction adding extra and/or larger vent/s is a must.

The real fix is a better oil ring package, second ring and a tighter ( hp specific ) top ring gap to control blow by. And you'll need a good cylinder finish for ring seat/seal.

Also, I've seen a fair share of leak valve guide as well. If N/A the exhaust side add to the crank pressure. F/I both in & ex can fill the case....

All this aside... try a catch can.

Surfer90291

Thanks for going into details, matter of fact I've been thinking of installing one, for this application would a can with a breather better than a regular sealed can? I'm N/A just a 5/16 spacer and HFC

I've seen a set up like this:


or like this:

guitman32

iTrader: (15)

Add a catch can if you want. But remember if it aint broke, dont fix it.

Surfer90291

I will try adding a catch can and I agree with your statement but just trying to resolve the excessive oil burning.

i-break-things

Using oil is a common issue, the fix is better crankcase ventilation with oil separation.

i-break-things

Either way could work.

If you are concerned about oil smell, porting the catch can back to the intake or intake tube is the trick. The catch can must have a media to slow the oil and allow it to separate from the crankcase pressure.

If you F/I a vented can is the best.

guitman32

iTrader: (15)

I am aware its a common issue. Nothing wrong with catch cans, but i wouldnt recommend anything more than that. My VQs both consume oil, and they run great. No sense in chasing the dragon over something that is normal for an engine this type and his age.

i-break-things

Agreed to a point, if you have a VQ you'll have to deal with the know oil loss or rebuild ( fix the oem issues). The great issue is the oil itself and where it goes. Its bad for the engine.

First, oil has an octane rate in barely into the two digits. Burning oil in the engine "can" do terrible things. Especially when spirited driving is involved.

Not to mention the additional carbon, soot, valve deposits, hot spots, cat damage, o2 fouling and ........

The difficulty is placing a good sized can in the engine compartment of a Z/G car.

Back in the day I'd use something like this.
http://www.petersonfluidsys.com/Imag...80011_34_L.jpg
Where do you a 3~5 gallon tank...

KornerCarver

iTrader: (2)

I think the original poster said the car has 111,000 miles. Burning a quart of oil every thousand miles is not really a big deal. I would suggest doing nothing as long as the engine is running good. Just check your oil weekly and add oil as needed.

Surfer90291

Just to add to the discussion, I've replaced spark plugs yesterday and through the spark plug hole I could see quite a bit of grime on top of the pistonheads.
I wonder if this indicates the excessive blow-by, if that's true a catch can should address the issue.

Just out of curiosity, has anyone ever tried decarbonizing the pistonheads by introducing atomized water through the intake?

guitman32

iTrader: (15)

Your motor has been running fine for 100k+ miles in its current state. Stop looking for things wrong with your car and just drive it. Hard. Best decarb procedure you can do.

i-break-things

Yes, water is one the best way to clean the carbon. Steam would work. Draw it into the intake...

i-break-things

Not really. That how the carbon gets burnt on and stuck in the cylinder. I've bore scoped motor with carbon build up and running them hard did not make a difference. One in particular was making over 1200 @ about 3 hp per cid.

guitman32

iTrader: (15)

My point was that if its running fine, you shouldnt do anything except drive it.

Surfer90291

Finally I was able to get all I needed and installed this catch can! After plugging the plenum port and the one on the intake pipe I connected the hollowed out PCV and the driver valve cover to the can. I can barely see a thin mist coming from the breather, seems to work. I'll post the results on oil consumption in a bit.

Surfer90291

After driving for about 350 miles, slightly beating on it altough never to redline, I noticed I'm still burning oil. Here's how much the oil level went down.
The catch can breather does smoke lightly but no liquid was trapped in the can. I haven't done a compression / leakdown test. Any ideas?

guitman32

iTrader: (15)

Drain the oil and measure how much you remove if you want to be sure exactly how much you are burning.

Surfer90291

I always let the car sit over night before I read the dipstick, it seems to be the best way to get an accurate reading. Also, it's my understanding that between the lowest reading and the Full notch there's one quart.

I'll do an oil change soon so I'll know how much I'll drain but what about the oil trapped in the oil filter and the engine oil passages?


UPDATE: I drained about 4 1/2 qts. More or less confirming the dipstick reading.