Start up smoke

[TPI Thomas]

Hey I have a 1986 corvette with only 54k mi But when ever the motor is cold and i start it up i get a puff of oil smoke. It goes away right away but I was wandering if this was a common thing or something I should look in to? Thanks for your help.

 

[Ken]

...if this was a common thing

Yes, it is a common occurence with the L98 engine. The exhaust valve seals don't do their job after a while and when you shut the engine down, the oil that collects on the valve stem leaks past the seal into the combustion chamber, where it is burned off when you start the engine. Hence the puff of smoke you see.

I had a brand-new K-1500 back in '88 that did the same thing from the start. GM changed the type of seal used, but I forget what year it occured. Hope that helps you Thomas.

_ken

 

[TPI Thomas]

Thanks alot! Thats what I figured because my car burns no oil when its running.

 

[Top]

When I got my 86 it did the same thing until I blew a head gasket. When I had the gasket replaced I had the heads rebuilt while they were off. Now I get zero smoke. I had 94k when I blew the passenger side gasket.

 

[billd]

i just fixed that problem

I just fixed that problem in my 84. Actually it was pretty easy to do. In mine it was just the valve seals.

 

[TPI Thomas]

what was involved in replaceing the valve seals?

What do you gus think about running synthetic?? Pros/cons my car has 54k mi

 

[billd]

Basically to replace the vavle seals is a pretty straightforward thing if you dont learn it the hard way like I did. Pretty much with a car that age the seals are probably shot.

To replace them
Basically you

pull the valve covers
remove the plug on the cuylinder your fiddling with
insert a tool to pressurize the cylinder (AutoZone $10.00)
apply compressed air to tool (just squirts air into the cylinder- through the spark plug hole)
remove rocker arm
install valve compressor ($8.00 Autozone) (use the rocker arm- nut to do this) (I had to bend to tool more than it already- was to fit it in but it worked well after that)
This is the tricky part

Make sure the air is going into the cylinder
pull on tool to compress valve spring (you may have to tap it with- a wrench just as to start to compress it to dislodge- keepers)
take out the keepers
put them somplace safe (you might want to purchase some- spares in case you lose them i did and i needed them)
pull the spring off
remove the cup seal at the head and the oring on the valve
install the new cup seal
THIS ORDER IS IMPORTANT
reinstall the spring
Compress the spring
install the oring in the SECOND groove on the valve
install the keepers and remove the tool

DO NOT release the valve compressor once the oring is installed and before the keeper is installed

install the rocker arm and set the lash by twisting the pushrod while tightening the nut. The pushrod should just turn with your fingers and no axial slop should exist.

After this is done done if the engine ticks just remove the vavle cover and set the valve lash with the engine running (kinda messy but really easy to do, use a feeler guage to find the culpit, since this is a no lash system the guage shouldn't go through )
just tighten the nut till the noise goes away.

Hope this helps :Twist

 

[billd]

One last thing if the keepers dont want to go in apply some grease to them this kind of helps hold them in place while you get the other one in (makes them sticky)

 

[TPI Thomas]

Thanks alot Billd!!! That helps a whole lot!!

 

[spyysee]

eventually, you WILL need to replace the valve seals. Probably sooner than later.
Very common on himi 350 mills.

 

[TAC]

On my '87 the exhaust are not the same style as the intake so my mechanic changed them when I wanted to get rid of the blue puff. The intake seals are a better design.