390 is blowing smoke from the drivers side...

[MaSnaka]

side pipe. I recently developed a noticeable miss at light throttle which seemed to go away at heavier throttle. It's hard for me to tell for sure what's going on by ear with the loud exhaust and rough idle. Yesterday I pulled the plugs (after the car has sat for 1 week) and found #1 black and wet, #6 was covered in thick black deposits, #2 & #3 had a light grey/silver color and the rest were a darker charcoal grey. I was surprised to see such a variety of conditions in the plug color. Maybe 1000 miles on the plugs, new carb AED 750 HP, new heads Edelbrock ported. I cleaned the plugs, gaped at .38 and replaced. Today the car started out running better but by afternoon I noticed the miss had returned and a lot of white smoke after light throttle to coasting and then when throttling up again. Just out the drivers side. At a heavier load the smoke would stop but I was taking it easy trying to get home.  Miss got noticeably worse which I figure was due to the plug fouling again. Am I looking at an intake gasket failure causing the smoke and fouled plug? An idle screw adjustment to correct the plug colors? Plugs are Autolite 3924.  I also checked the plug wires with my ohm meter and they ranged 99-117 with the two black plugs at 105. 

 Thanks,
 John

[jayb]

If you've got white smoke out the back, you've probably got water getting into the combustion chamber.  Could be an intake gasket leak, head gasket, or a crack.  Go for the cheap, easy fix first, and put in some sealer, like maybe the Moroso ceramic seal stuff; I've had good luck with that.  If it's a minor issue that might do it.  If not, you will have to start taking things apart, starting with the intake, to see if you can find the leak.  You can also try pressurizing the cooling system with air and listening at the spark plug holes or under the valve covers for a hissing sound; that can point you in the direction of the source...

[bartlett]

My first thought is intake.. 2nd thought is head gasket.

I would do a compression test on one good cylinder for a base line and one on the worst bad cylinder. then a leak down with radiator cap off and see if you get any air bubbles out the top of the radiator to rule out head gasket.

and is the coolant staying clean ? if its getting brown you got problems


just my thoughts ... I'm positive theres much wiser help on this site than me  lol ..... 

[bartlett]

another random thought ..... Retorque the intake as it might seal up a small leak ....