connexion2005

iTrader: (49)

Ok here is the wierd issue. For some reason, under WOT when the car is at operating temperature, the car will ocassionally have a light blue smoke. His car is a 99 SS. All he has is full exhaust and a lid. All four plugs on the driver side when you pull them have clear evidence of oil on them. This is the driver side only while the passenger side plugs remain bone dry! We have performed a full compression test on ALL 8 cylinders and the results came up with 170+psi on ALL 8. I understand that rings are a possibility but seriously on ALL 1,3,5 AND 7! This is very unlikely. Good maintainence has been done to the car. We are thinking it may be a PCV issue or possibly and intake gasket issue on the side of the manifold. If I remember correctly though I didn't think oil flowed near our intakes on Ls1 cars...We seem to be able to blow through the actual PCV valve but we haven't actually blown through the hoses to see if maybe they were clogged. Here is an option we were considering to test the valves operation. Just running the entire system without the actual valve to see whether or not it was causing a problem. We believe that it is PCV related since both valve covers breath independently and that seems to be on of the only ways that ALL 4 plugs could have oil on them rather than the unlikely even that ALL 4 piston rings are failing on one side! Thanks for all help and please toss us some advice!

Josh

BTW the car has gone 12.7 @112mph in the quarter and runs great with no SES issues.

Quickin

Need a valve job on the heads, the valve seals are bad.
I also, would get a cloud of bluish-white smoke when I would go WOT. I had the heads rebuilt and it 100% disappeared. When you go WOT the oil is pulled through the bad valve seals right into those pistons, from the oil thats up in the valve covers around the springs/rocker arms, on that side, causing the smoke. And it only happens when you smack the throttle because of that sudden decrease in pressure from going WOT.

When you turn the car off oil drains down onto those plugs from above, where those bad valve seals are.

This was my same exact issue and symptoms and the valve job fixed it.


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connexion2005

iTrader: (49)

possible but i just think it such a coincedence that only on that side there is an issue...

Quickin

This is just what my fix was for the same exact symptoms you're having.

I believe a leakdown test can tell you if the valve seals are bad. No???

I just don't see how oil can drip onto the spark plugs from anywhere else. Bad rings won't do it, they're underneath the spark plugs, oil can't go up.


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blownta00

yea hes right get a pressure test on the heads. its like 40 per side

connexion2005

iTrader: (49)

well if the pcv system is clogged or stopped up running from that side or at the valve then yes oil can be forced up through the rings since no PCV pressure is being vented from the case on that side.

tylerdj

iTrader: (31)

Sounds like the valve seals are bad and allowing oil to leak down onto the plugs.

connexion2005

iTrader: (49)

Talked to him earlier today and he says he did valve seals earlier this year. We are pulling the intake this weekend to see how much oil is in it and if the gaskets are still good. Just a clean up that is free to take a look at...thanks for the responses so far guys...

Quickin

Are you saying the oil would be forced up around all sets of rings, then travel further upward and into the thread holes where the spark plugs are?

hmmmmmmm.........I don't know.

Just coupled with the fact that you are getting a cloud of smoke when you smack the throttle, kind of confirms that oil is being sucked through the valve seals from the HUGE pressure drop from the pistons accelerating.

But I guess you never know what causes things.


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connexion2005

iTrader: (49)

Yes I am saying its possible. If you understand the way the PCV works on these cars, it its like this:

1. Air is sucked from the throttle body (fresh air tube) and into the front of the passenger valve cover where vacuum is created, from there a line is run from the back of the passenger valve cover into a y adapter behind the intake and then to the back of the drivers valve cover. As I mentioned before where it hits the y at the back of the intake I only talked about the point making up a part of the y. The other piece of the y runs to the intake manifold vacuum port on the passenger side at the front of the intake. So basically, the last to points on the trip through the pcv line are the driver side valve cover and then on up to the intake manifold. If the valve at the intake is not doing its job or is stuck or closed, then all that pressure will only get as far as the last point in line (driver side valve cover). That means that now we have all the pressure from the passenger side and the driver side stuck on that side now since the valve will not allow suction back into the intake. With that much pressure, your damn right it can make it past all 4 rings on that side. Look man it has to go somewhere and I have been talking with a couple of ASE Master Mechanics and its a very logical assumption. We pulled the valve out today and ran a straight through design without the valve under all driving conditions. And what do ya know, no more smoke after hard runs. Ofcourse all it probably needs is a new valve and it makes no since to run the system without the valve since oil consumption would be ridiculous. I appreciate all the concern for the valve seals, but guys they were professionally done 2,000 miles ago and that has been mentioned. I really don't think that was the issue. We are putting the new valve in tomorrow and hopefully that cures the cancer and this thread can serve as a way for people to understand the way the system works due to my novel of a thread and possible eliminate the difficulty of this issue in the future. Thanks alot and keep questions/suggestions/responses coming!

Josh

Quickin

You're saying the oil will go from the crank case (oil pan) up the cylinders and past the 4 rings on those 4 pistons?

What about pressure being released through the oil return holes in the head from the valve covers, back into the crank case?


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connexion2005

iTrader: (49)

Obviously vapors can move through the oil return holes but not 100% of it may make it back with a given PCV pressure. Its a known issue with PCV malfunctions man. I'm not making this up. Here are a few links to back up my info. Not saying these are written by the hand of god but there on a GN Forum and other sites that seem to be legit.

http://www.gnttype.org/techarea/engine/plugs.html

This one even states that the gasses will pass the rings even on a new engine.
http://www.econofix.com/pcv.html

http://en.wikipedia.org/wiki/PCV_valve

Why is it so hard to believe that blow by can't contain oil which would hit plugs. I piston going down into an area of extremley high pressure where oil slides past the rings could easily shoot a couple of inches up to the plugs.

Josh

Quickin

The oil on the threads of the spark plugs gets there "when the engine is turned off", not while the engine is running. As the car sits whatever oil is left on the valves runs down and gets on the sprak plug.

When an engine is running and getting blow-by all the oil gets burned and blown out with the exhaust. I doubt wet fresh oil can survive the combustion process, remain fresh and wet, and then work itself into the threads of the spark plug while such an explosive process is going on.

Key word: "gasses" Not wet, thick, fresh oil.

What tests are you gonna do to try and figure this out?
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connexion2005

iTrader: (49)

Good valid points. Basic tests will include pulling the 4 plugs on that side, thouroughly cleaning them running the motor through various cycles and then pulling them asap w/o allowing oil to run out from the valves. There is no smoke on startup which is why I have serious doubts that brand new valve seals are leaking. If oil were to run down from the valves then ofcourse with oiled out plugs, there would be smoke on start up would there not be. Look, we both have valid points IMO and its a difficult problem to diagnose. I'll keep you posted as we will be doing stuff this weekend...

Formula413

iTrader: (1)

I think Quicken is correct here. I also think I have this problem. Here's a question: the pictures in the back of my repair manual show a spark plug caked up with white ash and it says that this can be caused by oil leaking down through a bad valve seal. My #1 plug looked like this the first time I pulled it, and it was a different brand than the others so it had obviously been replaced. Has anyone ever seen that before? I'm not talking about white glazing like when a plug is run too hot, but rather white buildup on the electrode.

Quickin

When my valve seals were bad my spark plugs would also be caked up with white crud on all the electrodes.

connexion2005,
I had just a small puff at initial start-up, than while it idles warming up, nothing. But as soon as I went down the road if I hit the gas pretty good I left a trail of bluish-white smoke.
Also, my valve seals were so bad that the valves couldn't even stay in the giudes when the shop took my heada apart, they fell right out.


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2000blackz

i had this problem on my 2000 Z28 i replaced the o2 sensor on that bank and it fixed it, my guess is that the o2 went out and it started dumping fuel in those cylinders causing it to dry the rings letting oil by, but on my car it was a light coat of oil on the plugs but thats just my guess not a professional opinion.

2000blackz

formula413 the first engine i had in the car had the same problem, it had a cracked piston and a loose wrist pin in the #1 cylinder that eventually ate the cylinder up, hope you have better luck than i do

connexion2005

iTrader: (49)

The main reason I am even fighting for my theory is due to the fact that both o2's are working correctly, all valve seals have been replaced (exhaust/intake) and the motor makes great compression. I keep getting told no no thats not right its this. Well "this" or "that" people keep referring to are things that have been checked/repaired so please stop telling me its things that have been replaced. I appreciate all help but guys alot of you are suggesting things that have already been checked/repaired. It would be like you getting a flat and saying you already replaced the valve stem since it was leaking but can't seem to find the flat and I keep telling you its the valve stem when you know damn well that you replaced it 1 month ago and its not leaking. Just stay open to ideas ok...I will be sure to post the remedy when I find it. The thing is we have had the pcv valve out for 2 days now and no signs of smoke whatsoever so we are highly sure its the valve. We are replacing it tomorrow and if that cures it and no oil ends up on the plug threads again than you surely must be willing to believe that this was pcv related right?

Quickin, I realize that the combustion process is very violent and explosive, but oil burns extremley slowly compared to gas which still leads me to believe that its highly possible due to blow by. Sorry for being so ignorant to some of the suggestions and I know I seem to be an ***...lol. Im just convinced that its not seals since they WERE JUST DONE! Seriously how are you going to still say its seals when only (1,3,5 and 7 are the plugs with oil and that just happens to be the driver side head?) 4 out of 8 do it and they are all on one side. Are you really saying that out of 16 valve seals replaced, that 4 exhaust, or 4 intake or all of those seals are responsible on that side. 8 possible brand new seals on one side leaking! Very, very coincedental if its true. Just some food for thought. I dont see how you can't side with me on the fact that the way the stock PCV runs that that side of the motor is that last point vented before it enters the intake manifold. Keep the thread rolling guys... . This is all a friendly debate BTW. Everything is appreciated even if not agreed upon .

Quickin

Hopefully it is the PCV. That would interesting. I think I understand what you're saying but I'm still trying to figure out how the oil can do what you say, but we'll see soon enough.

Let us know.

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