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HELP - Mystery Smoke

R

Roy M

Guest
While driving the car this weekend, was stopped in traffic, noticed pale blue smoke coming from the exhaust, quite a bit. Got the car to the house and it was still coming out of the exhaust but not near as bad. Drove the car yesterday, did not notice any smoke at all except when I pulled back in the garage could see a faint bit of smoke. Checked the oil level both times and it was at proper level. Today, I removed and replaced the spark plugs, all the ones that I removed were what I would call the proper color, a grayish color. Talked to an engine builder and he said that he thought the plugs looked ok. He suggested that I change the PVC valve which I then did. The valve that I removed would rattle [my understanding
they are good when they rattle]. Just took the car on about a five mile trip and no smoke at any time and no smoke idling when pulled back in the garage. I am at a complete loss. The motor only has about 5000 miles on it since rebuild and this is the first time anything like this has happened. The motor still runs strong, might have a half-quart of oil consumption around 2000 miles. One thing that I want to ask is, My PVC valve is in the left valve cover between Nos. 1 & 3 cylinder, on the right valve cover, I had put a chrome breather with no hose running to the breather [chrome aftermarket], do I need to run a hose from this hole in the right valve cover to the air breather to get a better flow of air into the engine. Could this smoke be coming from a carburetor condition?? Running the 670cfm Holley Street Avenger Carburetor. Have adjusted the settings on it, could I have screwed something up there?
Any and all thoughts would be very much appreciated as I am at a loss on this.

Thanks
 
R

rpounds

Guest
Blue smoke indicates burning oil. Even though the PCV valve would rattle, it does not always indicate that it is working properly. I had a 94 that had to have the PCV replaced every 10,000 or so. Otherwise, it would blow oil past the front crank seal. The engine is pretty fresh, so I would expect a fair amount of blow by, which will destroy a PCV fairly quickly. Since changing the PCV seemed to correct the problem, I would suspect that was the only thing wrong.

Just my 2 cents . . . I'm sure others will chime in here. . .
 

Ken

Gone but not forgotten
Joined
Jan 30, 2001
Messages
8,236
Location
Hermosa Beach, CA
Corvette
1987 Z51 Silver Coupe
Are your valve covers baffled to prevent excess oil from being pulled into the intake stream through the PVC?

_ken :w
 
R

Roy M

Guest
Yes, the valve covers are baffle type. That was one of the questions the engine builder asked. He said he had saw a lot of motors do exactly what you were implying.
Hopefully, changing the pvc valve will solve the problem. Will keep a close watch on it for a few days before I start looking elsewhere.

Thanks
 
J

jkern

Guest
Try replacing the power valve in the carb. If the carb has not been rebuilt in quite a while, try rebuilding it. Check the oil to see if there is any fuel in it. A bad power valve can cause raw fuel to leak into the cylinders, around the rings into the oil which may cause an internal engine explosion when starting. JK
 

ggaagg57

Well-known member
Joined
Feb 6, 2002
Messages
120
Location
alpharetta,ga,usa.
Corvette
68,502 convt. ,- &81,4speed ,80 4 speed, 70 454
it wouldn't hurt to ck brake fluid, if master is leaking into booster. it can be sucked into motor and burned. didn't you say there was no using of oil? something to ck anyways .
 

bradfordsvettes

Well-known member
Joined
Mar 28, 2001
Messages
549
Location
Boston, MA area
Corvette
jewel blue 61.cranberry 69 t-top.black rose 92
smoke

a bad modulator at the trans if automatic will smoke if diaphram is bad:w
 
R

Roy M

Guest
Well, I have checked everything and found nothing. Did change all plugs, they were in good shape, the PCV valve did rattle but I replaced anyway and as of now, no smoke. Hope that was the fix, if not I will be back to ask for more help.
Thanks for all the replies.
 

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