'49 Exhaust Smoke

[49 Dodge Dude]

Hey, all. I have a '49 Dodge Coronet that I just picked up a few days ago. Noticed on the way home that it smoked (not a lot but continuous.) It was dusk, so I really couldn't tell the color of the smoke, but it did have an oil smell to it. I took out the plugs to examine them - all six had a pretty good covering of black soot, but did not look oily. Any ideas as to where I should be looking for the source?

[Reg Evans]

Make sure you choke if fully open after warm up.

[Phil Martin]

My 50 coronet smokes on start up after sitting a few days. When running at speed if I let it coast a while it will blow blue smoke when I step on it. Runs great, compression 90 to 95 [ a little low?] plugs all look normal not sooty or oily.?????

[Plymouthy Adams]

worn rings, valve guides...decel is higher vacuum..all suck and no blow..thus the ingesting of oil/oil vapor

[aero3113]

Hey, all. I have a '49 Dodge Coronet that I just picked up a few days ago. Noticed on the way home that it smoked (not a lot but continuous.) It was dusk, so I really couldn't tell the color of the smoke, but it did have an oil smell to it. I took out the plugs to examine them - all six had a pretty good covering of black soot, but did not look oily. Any ideas as to where I should be looking for the source?

Do you know how long the car has been sitting before you picked it up? The rings could be stuck or worn allowing some oil to pass by. Did it smoke the whole ride home or did it stop after a while? You may want to do a compression test on all cylinders and see what you get. Its an easy job to hone the cylinders and put new rings on if you need to. While you are in there you can replace the rod and main bearings if you have low oil pressure also.

[greg g]

You should do a compression test, get a reading of each cylinder both dry and wet (squirt a bit of motor oil down each spark plug hole before attaching the compression gauge). This will give you a better idea of what condition your cylinders are in.

A common failure on these cars is rings cracking due to wear of the lands. This will cause loss of compression and will allow oil past what left of the rings.

A vacuum gauge attached to the engine will alos help diagnose the problem.

Edited September 10, 2010 by greg g

[48mirage]

"...covering of black soot, but did not look oily."

This description suggests it's running rich.

[Plymouthy Adams]

as Greg said, do a compression test..if even across the 6...bring it to the best state of tune you can get it and drive under some of the Lou Earle recommended conditions/additives..then see if things improve from there..

[49 Dodge Dude]

Do you know how long the car has been sitting before you picked it up? The rings could be stuck or worn allowing some oil to pass by. Did it smoke the whole ride home or did it stop after a while? You may want to do a compression test on all cylinders and see what you get. Its an easy job to hone the cylinders and put new rings on if you need to. While you are in there you can replace the rod and main bearings if you have low oil pressure also.

It did smoke the whole way home, and it still smokes. I plan on doing a compression test Sunday, so I'll get an idea what condition they are in. FWIW, the oil gauge stays steady at about 40, so it looks like my oil pressure is pretty decent.

[dynaflash_8]

sounds like worn valve guides.

Just think of it as extra top end lube

Or that now you have an excuse to flog the throttle to "clean the carbon out of her"

[james49ply]

if the plugs are covered in black soot (not oily) a too rich condition will cause that, my old engine that burned oil, the plugs were clean as it only burned it when decellerating. but black smoke under power could be over rich fuel, like the choke is stuck partially closed. I can't see that worn valve guides would do it, as they are upside down and oil would run down the stem to the tappits and they don't use valve seals anyway. worn guides casing oil consumption is problem for overhead valve engines, not flatties.

Edited September 13, 2010 by james49ply