hey guys i nope y'all can help me. i was planin a cam swap in my 86 LB9 this winter, but i have a problem that needs addressed first. my car smokes upon startup. and smokes when the engine speed is increased. it does not smoke noticably at idle, steady RPM, or upon deceleration. for instance when i am at a stop light idling it does not smoke , but as soon as i touch the pedal to acclerate, it billows smoke for about 2 seconds. i replaced the valve seals about 6000 miles ago(this fixed my problem for about a week, then it cam back worse than ever). what is the deal? my buddeis car does very near the same thing. i am going to run a compression test over my thinksgiving break. and check my PCV valve. what else do you guys think? my motor runs real strong and has only 42000 miles on it. i change my oil every 2500 miles too, and the oil that comes out is always clean. i have really tried to treat this engine well and the smoking has gotten worse in the last 5000 miles or so. i want to put in a hotter cam but if my rings are broken or have lost thier tension, then i have other things ot worry about. any help u guys can give woudl be appreciated. any mods are in my sig.


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86 IROC
43,000 miles
305/700R4/3.23 gears
maroon, gold stickers, black interior, T-Tops.

current mods.
shift kit
headers
cat back exhaust

mods planned for this winter
cam
3.73 gears
subframe connecters

[This message has been edited by 1MeanZ (edited October 28, 2001).]

 

You can run a compression check to verify your compression, but if you're smoking on acceleration it's coming from the heads or intake, not the rings. Rings would smoke all the time, especially on decceleration. You probably have worn valve guides, and changing the valve seals will only temporarily stop the smoking. Before any upgrades are done, you might want to get those heads rebuilt and have new valve guides installed, or just pick up some aftermarket heads. The biggest gains in HP are going to be in the heads and exhaust anyway.

 

By the way, my L69 had the same problem. That's why it has L98 aluminum heads now. The L69 heads were notorious for their valve guide & seal failures. If you decide on aftermarket heads over rebuilding the stock heads, keep an eye on the combustion chamber cc, your L69 heads are 58cc. (L98 aluminum heads are also 58cc) Going higher on cc will cause compression ratio reduction and cost you free HP without proper pistons. If you get your L69 heads rebuilt, be sure to port match them to your intake gasket, and it helps to port your intake manifold also. You can pick up some free HP and reduce a carbon buildup area at the same time.

 

foursure the valve guides, looks like the heads will need to be rebuilt.

 

wow thanks for the responses. i was almost sure that it was the worn valve guides hogging out my new seals. and the car has too few a miles and runs too strong to have bad rings, besides rings smoke all the time. anyone else have any opinions? other suggesions?

 

What kind of seals did you replace the old ones with? If it wasn't a high quality set of PC seals then I wouldn't think it's the valve guides, just the seals. IMO, I wouldn't be looking for the valve guides to have worn that much on a car with so few miles.

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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

ttt

 

you have to remember that mostof our cars where BEAT by former owners, I know my was you should have seen the 1/4 of crap in the heads....ewww, everything was totaly destoryed except for the heads and up.

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1987 Black 305 TPI 5spd IROC, G92, 9-bolt 3.45, Lowered, Cat-back, Air Foil, Sub Frames, Huge sways.

AIM: IROC 5spd
http://www.geocities.com/chevy5spdiroc/87Roc.htm