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papa2 11-18-2005 10:40 PM

Blue smoke
 
I have an 87 vette and get some slight blue smoke out the exhaust when I first start it up in the morning. That's the only time I see it. Am told by a mechanic who has a vette that it's common and that it's probably a valve seal, and not to worry about it. I would suppose pulling plugs to see which one(s) show oil deposits on it would tell me which one(s) is leaking. Anybody have this problem and ballpark($) to change seals(one, one side, both sides)? Thanks

SkipS 11-22-2005 01:46 PM

RE: Blue smoke
 
You have leaky valve seals/guides. Your mechanic is right, don't worry until it gets worse. When it does get worse, pull the heads and have the seals replaced. This will be a great time to get the heads reworked completely. Have them checked for cracks, surface ground and a good performance valve job. This will also be a good time for porting and polishing. That will cost more money, but will add to the performance. When the oil burning gets to about a quart per 2000 miles, I would pull the heads. However, the plugs may start fouling before then, which will require that the valve job be done.

Lee Willis 11-25-2005 01:35 PM

RE: Blue smoke
 
Skip S is right on all counts.


crvttbass 12-20-2005 10:48 PM

RE: Blue smoke
 
I not really disagreeing But if you have more miles on your engine and you do a valve job you are likly to end up with compression ring problems. I have seen it with my own eyes or I wouldn't say anything. depending on the miles on your engine, the rings and the valves are wearing and fatuging equally. If you do a valve job it is possable that you will lose your rings shortlty thereafter. I found out the hard way when I first started working on engines for others. I did exactly as stated above for a guy, Not the performance mods but complete vave job. Granted not a Vette. But asmall block 327. Guides, seals and valve job. He called me two weeks later . Didn't have enough power to get out of his driveway. I checked and he lost most compression on 6 of 8 cyls. . I ended up redoing his motor. I later talked with a retired race engine builder and he said that thats what happened. The fatuiged rings couldn't handle the tight seal of the new valves. I had no reason to dought him as it all fit. I'm not sure but depending on the year of your engine some guides had the umbrella type valve seal. You can put them on without tearing down your engine. I've done it several times on other GM engines. (never a Vette though) But you need to know what your doing and have the correct tools. as pressurizing the cyl. with an external air source is required to hold the valves closed. It's actually quite easy with the right tools.

It all depends on how much the smoke is bothering you.

Just my opinion.

Good luck with it, whatever you do.

Lee Willis 12-21-2005 12:05 PM

RE: Blue smoke
 
That definately a point and I've had the same thing happen to me, but also I've done valve jobs and guide replacement on several V8s over the years including a 327 and a 307, as well as a bunch of Healey 3-liter sixes, where the valves and guides were shot, but they got another 30-40K miles before they needed rings. An Olds 425 from the mid 60s I did the valves on in about '82 went another 80K before the owner just junked it cause the car rusted out.

Given everything I've heard about this, I wouldn't do a thing until it got worse and then I'd replace the whole motor with a crate engine. An '87 is getting on close to 20 years old and everything in there has to be getting tired.


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