I just bought a chevelle that smokes like crazy. Just idling it looks like a hollywood smoke machine. I was wonder how you can tell if its valve guides or rings that ae bad

Just bought???? was it sitting for a long time? Is it just old gas? What color is the smoke?

White smoke = steam...coolant escaping into cylinders.

Black smoke = overly rich fuel mixture...carburetor problem.

Blue smoke = oil escaping into cylinders...worn internal components.

If you're experiencing the third scenario, anticipate rebuilding the entire engine. A fresh valve job will make short work of worn rings. New rings will quickly overpower worn valves.

Yep, I'm bettin' on the rings. If it was valve guides, it would tend to smoke on start up and when you got on it. If it's smoking all the time, it's more than likely rings. Like Bill said, this only applies if it's blueish smoke. If it's pluming white smoke, it's a crack somewhere or a head gasket. Either scenario is common.

Seen a bad modulator on the trans cause that also.:)

the smoke is white and the car was sitting since july. I thought it may be a head gasket too but I checked the oil and it is black no milky substance at all.

If it has a modulator valve, pull te vaccume line off and plug it and see if the smoke clears up. Just hope it didn't freeze and crack a head or something!

the smoke is white and the car was sitting since july. I thought it may be a head gasket too but I checked the oil and it is black no milky substance at all.

Does it smell sweet? Is there antifreeze in it? It can still be water getting into the combustion chamber and not in the oil.

I'm not sure how the transmision modulator would create smoke, but I will try it anyway

I'm not sure how the transmision modulator would create smoke, but I will try it anyway

When the vacuum modulator diaphragm goes bad transmission fluid is exposed to engine vacuum with predictable results. The vacuum modulator is a pneumatically operated hydraulic piston which moves and exposes/covers various oil ports to control part throttle shifts.


It is a self solving problem however. If you ignore it long enough you run out of transmission fluid and your car stops.

I remember reading in an old HOT ROD about dripping tanny oil into your carb to get rid of carbon in your cylinders, they said it would smoke like hell and you would have to change your plugs. I don't recall what color the smoke should be. thanks for the info changing the module would be the easiest fix

I remember reading in an old HOT ROD about dripping tanny oil into your carb to get rid of carbon in your cylinders, they said it would smoke like hell and you would have to change your plugs. I don't recall what color the smoke should be.

Never heard of this....have heard of pouring a glass of water down the carb to "steam clean" the cylinders...though I've also heard this isn't recommended.

I have heard of it, Hell I've done it. it is white smoke and alot of it. It does clean up the carbon but is probably not epa aproved:) . neighbors dont like it much either as the smole hangs around. but that was years ago, Ive grown up since then

Take the plug out of one of the cylinders and take a compression reading. Put a couple shots of oil in cylinder and take compression reading again. If reading is higher the second time around it is the rings. If not it is probably the valve guides.

I have heard of it, Hell I've done it. it is white smoke and alot of it. It does clean up the carbon but is probably not epa aproved:) . neighbors dont like it much either as the smole hangs around. but that was years ago, Ive grown up since then

It makes the same smoke the engine oil does.

Water = gets into the carbon and the flashes to steam. Basically exploding the carbon from wherever it is stuck. IE: Piston top.

( Water, when changing state from liquid to vapor, increases in volumn on the order of 10,000 to 1. Hence the explosive nature of the process. No worries however. Your engine is used to stuff like that)

You ALWAYS pour the water into the carb SLOWLY and at roughly 2500 RPM. NEVER attempt to pour water into the engine in sufficiently large quantities to stall the engine. Just pour it into the engine slowly while racing your engine.

Tranny fluid = Gets into the carbon and dissolves it. The tranny fluid method is slower which is why you pour it in slowly at the start and then finish by drowning the engine till it kills. It takes a lot less tranny fluid to do this than water since when you start to pour it in heavily you quickly foul your plugs and that is what kills the engine.

Let it sit for a 1/2 hour or so and then start working on getting the engine started AFTER you have taken the plugs out and spun the engine over a few times to get the excess fluid out of the cylinders. During this time you should have already removed and cleaned your plugs. They will be very fouled by the tranny fluid. CRC Brakleen will remove the fluid in an instant.


Tranny fluid is probably the better method of COMPLETELY removing carbon from the piston top and the combustion chamber but it is far messier than water.

Water will remove just about all of the carbon that would ever create "hot spots" that could be causing ping or detonation problems. Its cheaper and far less dramatic too :)

I have heard of it, Hell I've done it. it is white smoke and alot of it. It does clean up the carbon but is probably not epa aproved:) . neighbors dont like it much either as the smole hangs around. but that was years ago, Ive grown up since then

Hey that sounds like an excellent way to piss off the neighbors, especially if the exaust and the prevailing winds were blowing IN THEIR DIRECTION!!!:D

Just kidding....don't think I'd do that....I'll bet it would help out in the summertime to keep the mosquitos away. :thumbsup:

Make it a new years resolution for it to quit smoking.

If the car has been smoking for a while it may take some time for the exhaust system to clean itself out. I put a rebuilt engine in a customers car and it still smoked for a few days until the crap got burnt out of the exhaust. Also I have seen lots of Chevies that had the oil drain holes in the cylinder heads plugged full of sludge. The valve cover would fill up with oil because it could not drain back to the oil pan and then you have a really bad smoke problem.
Paul

When we did an engine swap to a crate motor in a friend's El Camino a year ago, it smoked white smoke badly from the old gas in the tank. When it used up that gas and we put fresh gas in the tank, it quit smoking. The old gas wasn't more that 6-8 months old then.

we always used a couple cups of diesel fuel slowly poured down the carb while working the throttle....i guess it burns hotter and cleans up the carbon in the chambers, it never failed....to make a spectacle :)

lol, seriously, it works, and it beat buying a can of 104+ back in the day, you remember, when we all had the hi compression motors and "ethyl" disappeared?