420A Yellow Tip Spark Plugs?

[XdsmdemonXRS]

Hey guys, i been having a problem with my 98 esi . After it heats up, a bluish tint smoke starts coming out of the exhuast, pretty heavily too....not a crop duster tho ...now of course , im thinking oil buring right?....well as the heading says, i pulled out 4 YELLOW tip NGK's.... not a single once of carbon or anything....and i dont mean a yellowish tint, i mean yellow period....on the electrode as well...so to put it plainly, im stumped on this one! Any ideas?

 

[Bender]

Yellow means the plugs are burning fine.

 

[XdsmdemonXRS]

Yellow means the plugs are burning fine.

K, thanks for the reply, but do you knwo why im getting a bluish tint smoke after it heats up?

 

[Defiant]

Time for a cylinder leak-down test. Sounds like you're coating the plugs with burned oil.

Reading plugs in the era of closed-loop feedback fuel injection is as pointless as our ignition systems are. Not that it was ever really much use in the carburetor days.

 

[Bender]

How many miles are on the car? My guess is your valve seals are leaking. If they are, you will notice that it will burn more at start up after the car sat for a while. (More of a chance for oil to leak through the seals and sit on the valves) 4G63 seals are about $30-$40, and you just got to pull out the spring around the top that holds them on, and then pull out the seal. I don't know the procedure for the 420a though. Pop your valve cover off and use a flash light to see if you can see any tears or en longed opening on them. A compression check may not show bad seals because the air seals on the valve and the seat, the oil seals are above the seat.

Edit: I did a search, seals are 25 plus 9 shipping http://cgi.ebay.com/ebaymotors/420A...015QQitemZ250110755906QQrdZ1QQsspagenameZWD1V

If you don't feel comfortable pulling your head off, and pulling out your valve, have a machine shop do it. It wouldn't be a bad idea to have new valve guides installed if your taking it to a shop (you need a special tool). If your doing it at home, put the valve in, then pull it out 1/32 of an inch and wiggle it up and down and side to side. Observe the play, you only want a little at most.

 

[silver bullit]

post a pic

 

[Cs4g63]

Your piston rings could also be going bad. Just another option.

 

[XdsmdemonXRS]

Ok , good stuff, heres the thing tho...there is NO TRACE of oil or carbon on the electrodes...just the yellow ...theres a little oil on the threads but thats it....and ,also, the smoking doesnt even begin to start til after its at operating temp. So i cant see how its the valve seals or even rings, the car has 98k on it. As far as mods go, Screamin Demon Coil, CAI, Header, no cat , Oil catch can , ground kit, UDP, and motor mount inserts. Car does currently ,also, have an exhuast leak. I have heard one person say it could running extremely lean and a possible headgasket staring to go?

 

[Bender]

It is possible, but your car would be running abnormally hot because the combustion gases would either be going to your oil jackets, or your water jackets. After you run your car for a while, shut it off and listen if your antifreeze is boiling (common sign).