Blowing smoke. I think I'm going to be sick.

[Paranoid]

I last ran my vette about 2 weeks ago to a local car cruise. It ran great, came home and put her in the garage. Uneventful day.

Today we planned to go to another cruise, so I go start her up and back her outa the garage and after a few minutes theres blue-ish smoke coming from the drivers side exhaust. Nothing from the passenger side. I mean a lot of smoke. Yeah, I think I'm burning oil.

There's no difference in idle, it's not missing or struggling. Nothing! Everthing else seems fine. :confused Still pulls strong.

Could it be caused by miss adjusted valve lash? My worst nightmare would be rings. I'd really hate to pull this engine again.

The only other clue/symptom was I noticed what looks like oil/grease dripping onto the exhaust manifold. Don't think the smoke was caused by this because the smoke is definetly comming from the exhaust tip and it's blue. :cry

Here's a couple pics of the exhaust drippings. I don't think I let the engine run long enough to burn off. It's only dripping from #1.

 

[henny496]

Smoke

Hello
It could even be a bad valve seal. They are not hard to change, if that is the case
take care
Tom

 

[IH2LOSE]

Whats the history on the motor fresh rebuild?

just a top end?

I would pull the plugs and see what they look like.

If number one is wet and oily i would do a wind test and a leak down test.

Sorry for your troubles

 

[Paranoid]

Whats the history on the motor fresh rebuild?

just a top end?

I would pull the plugs and see what they look like.

If number one is wet and oily i would do a wind test and a leak down test.

Sorry for your troubles

Engine is all new. I finished the bottom up rebuild last fall. Has about 1,000 miles so far. I followed the usual easy break-in.

Heads are GMPP Signature Series, TRW pistons, chrome moly rings etc....nothing but good parts.

 

[IH2LOSE]

Did you run the motor anytime after you seen the smoke.


We all know blue smoke means oils getting in.So a simple thing is you could have lost a valve seal and it dripped by when sitting

or it could be the ring.

Again sorry for your troubles

with the oil you have around the excahust manifold I hate to say it but my guess is a ring.
Check compresion

 

[John Mcgraw]

If the leak down test looks good, then a good probability is the intake gasket. Look for the plug that shows signs of oil and check the seal around the intake port at the valley. It is not very likely that a valve seal would show up that much at idle. They really show up at high rpm's under closed high vaccum, like going down hill. If it only smokes for a short time after start-up then it could be a bad valve seal that is leaking by when parked, but if it continues after warm-up then it probably is not.
I would bet that that is not an oil drip from the valvecover, but oil blowing out the joint at the manifold/head junction. I'll bet if you run your hand around the joint, you will find an exhaust leak there. There is no evidence of the oil running down from above. This makes it pretty obvious which cylinder is oiling, but I would still give better than even odds that the problem was at the intake gasket. Run around the intake bolts again with a wrench, and make sure that they are all tight. It is highly unlikely that a ring would go bad that fast on a brand new rebuild!


Regards, John McGraw

 

[Tom Bryant]

I agree that it is most likely the intake gasket allowing vacuum to suck in oil from the valley. I can't imagine you could get that much oil past a bad valve seal on a new head. I've taken apart high mile heads with hardly any trace of any valve seals remaining at all and they didn't blow liqued oil out of the exhaust.

An engine with a broken or stuck ring will though. This should not be your problem with new pistons and rings but if the rings were installed with way too tight to zero end gap one could have broken. Do you know that all rings were checked in the hole they were installed in?

Tom

 

[henny496]

smoke

Hello
I did not realize you have a new motor. Bad valve seals are usually only problems on older stuff so the motor puffs on start up mostly(loose guides)
Tom

 

[vintagecorvette]

I had the same problem. It turned out to be bad rings. They collapsed. Do a compression test then a leak down, so you get the full picture of what is going on. oWEN

 

[Paranoid]

Thanks for the ideas guys. I did check the ring gap in the hole and I think they were ~0.022, I could be wrong because that was 2 years ago.

I'll work on the compression & leak down tests. Probably gonna be 2 weeks or more till I get time to work on her.

 

[Rowdy1]

Same Problem.........

I had head bolts that weren't sealed with the right stuff and it smoked and had oil in the exhaust, just a thought and an easy fix. Good luck.

 

[IH2LOSE]

Intake manifold leak is an excellent thought.That could move alot of oil. Besides a wind test (to eliminate a bad ring) What else might he try to determine if its the manifold. Any idea what would make it ok for 1000 miles and then not ok the next day.

 

[Paranoid]

Earlier this morning I took the dog out so I thought I'd poke around a few seconds before I had too get off to work. I checked the radiator and there doesn't seem to be any oil mix. One thing I did notice is that my over flow recovery tank is completely empty. That has never happened in the last year the engine has been running.
Another note is that there was a lot of smoke, not just a little. So much so, it reminded me of when I had a head gasket go on my old Suburban.

 

[74bigblock]

If it were a head gasket... you'd most likiely have water in your oil or oil in your water. Might it be as simple as a valve cover gasket? Did you pull it to see if it was pinched?


Off topic: On another note what brand is your little air filter... and where did you get it?!

 

[vintagecorvette]

You would not necessarily see oil in the water if you popped the head gasket between the pistons. However, it would pressurize the system and you should smell fuel. oWEN

 

[Tom Bryant]

That may not be oil on the exhaust manifold but a combo of carbon and steam. With the overflow tank empty I am starting to lean towards this. If it's a head gasket it's been leaking long enough to use the coolant in the overflow. It may have been a minor leak just sucking in coolant and blowing carbon/steam out of the exhaust until your last cool down cycle. I'd start out with a simple compression test to see if #1 is up there with the rest or if any other cylinder is out of range. Then go on from there with more serious testing if this shows nothing.

Tom

 

[Paranoid]

Thats one reason I like a clean engine. At least I can spot new leaks. :L

I'll follow all your advice....probably be a while though, family, work and volunteering kinda gets in the way of my "Vette" time.

 

[Mike McKown]

Thats one reason I like a clean engine. At least I can spot new leaks. :L

I'll follow all your advice....probably be a while though, family, work and volunteering kinda gets in the way of my "Vette" time.

Crank it up and stick your hand in the exhaust smoke. Smell your hand. If it smells like oil, that's one thing. If it smells like anti-freeze, that's another. Did you seal your head bolts before you installed them.

 

[Paranoid]

Crank it up and stick your hand in the exhaust smoke. Smell your hand. If it smells like oil, that's one thing. If it smells like anti-freeze, that's another. Did you seal your head bolts before you installed them.

Yes, I used sealant on all head bolts.

 

[Rowdy1]

Ya Know................

When I replied to this the first time, it was late, now that I read it again, it WASN'T my head bolts that leaked, it was the rocker arm bolts. Drove me nuts for a week, did the leak down, you name it, nothing. Had the intake back off and looked with a mirror, BINGO, raw oil dripping off them in the exhaust ports. Pulled them one at a time, sealed them, the mufflers dried out, no more smoke or raw oil.