White smoke from passengers side exhaust

[David H.]

[Ed S.]

Re: White smoke from passengers side exhaust

Are you seeing "smoke" as in unburned or incompletely burned petroleum (oil) or "steam" from vaporized coolant. When it exits the exhaust pipe steam will just "disappear" into the atmosphere quickly - smoke dissipates, or spreads out and thins out in the atmosphere.

[Bill W.]

Re: White smoke from passengers side exhaust

David,
Next time you start your car cold, put your hand in the exhaust vapor exiting on the right side. If your hand smells like gasoline that's okay, but if it smells like antifreeze you have a problem. Coolent should NEVER leak into a cylinder. It's okay for hot exhaust to condense moisture and blow it out as the pipes warm up but once the pipes are at operating temp no moisture of any kind should be coming out. Bill

[David H.]

Re: White smoke from passengers side exhaust

White steam from coolant.

[Frank D.]

Re: White smoke from passengers side exhaust

Very first thing I would check is the heat riser (flapper) on the passenger side exhaust manifold, make sure it opens and closes freely and the spring action operates correctly. There are easy-to-use kits to check for combustion gases in the coolant if you think you have a leak (head gasket, etc)
https://www.harborfreight.com/combus...tor-64814.html

I would also be tempted to check the torque on the intake manifold bolts - but that's just me...

[Edward J.]

[David H.]

[Frank D.]

Re: White smoke from passengers side exhaust

The heat riser was just something unique to the side you're having issues with and easy to check out on the car in 30 seconds - no need to pull it.
It doesn't take a lot of coolant to make smoke so you might not see the level dropping dramatically for a while. I still say the combustion gas test kit is a good idea.

I'd be suspicious of that intake repair... I haven't heard anything about the bolts "leaking" anything except motor oil wicking up if there isn't thread sealant on certain bolts.

[Ed S.]

Re: White smoke from passengers side exhaust

Short of pulling the head and doing a visual inspection, you might consider doing an compression and a leak down test on the cylinder bank in question. If there is a leak - anywhere - valve, piston rings, gasket - the leak down test should expose it.

[Duke W.]

Re: White smoke from passengers side exhaust

When cold the heat riser valve is closed which forces exhaust gas from the right bank through the inlet manifold in a passage under the carburetor to the left hand exhaust that provides heat to evaporate the fuel. This results in good "drive off" behavior. Even in sub zero weather you could usually drive these cars off once the idle stabilized, like only a few seconds after engine start.

Often in cold weather (especially in damp conditions) when you started the engine you saw "white smoke" coming out the exhaust pipes, often more on the right than left because there was so little flow through the right that water from the combustion process rapidly condensed in the cold exhaust system causing "white smoke"... like a cloud in the sky.

Once the heat riser opened from exhaust heat expanding the thermostatic spring and things warmed up including the exhaust system the water stayed in the vapor state on both sides until well clear of the exhaust system and dispersed.

No more "white smoke".

Since most of us don't drive in cold weather it's a good idea to wire the heat riser valve open. This usually won't cause any cold drive off issues in mild weather, but it could save the RH exhaust system, which would usually rust out after less than a handful of years due to all the condensation, especially in winter. Wiring the heat rise valve open can also mitigate fuel percolation and high operating temperature issues.

The above is maybe all you are experiencing. It's November. I don't know where you live but many parts of the country are seeing morning temperatures in the forties or less, which can cause condensation. If you're not seeing a decrease in coolant level and can't detect a sweet smell or taste from antifreeze in the exhaust (assuming you are using an ethylene glycol based products), then all you may be seeing is cold start condensation.

Back when I lived in Seattle, cold condensation was common on all cars on cold, damp winter mornings and my SWC's RH muffler rotted out in less than five years.

Duke

P.S. Fuel injection engines, both vintage and modern, don't need heat risers because the proper amount of fuel is injected into each port (or cylinder if direct injection) which evaporates as it's drawn into the cylinder and during compression. Carbureted engines dump liquid fuel into a plenum, which must then evaporate for distribution to the cylinders, which can be an iffy issue, especially on a cold engine.

[James N.]

Re: White smoke from passengers side exhaust

.......

Since most of us don't drive in cold weather it's a good idea to wire the heat riser valve open. This usually won't cause any cold drive off issues in mild weather, but it could save the RH exhaust system, which would usually rust out after less than a handful of years due to all the condensation, especially in winter. Wiring the heat rise valve open can also mitigate fuel percolation and high operating temperature issues.

........

Duke

......

When I put my 67 back together this summer I ditched the heat riser and bought a spacer from Paragon which I installed in it's place, just for this reason. Non-judged driver.

[Duke W.]

Re: White smoke from passengers side exhaust

l did the same to my SWC back in the seventies when I rebuilt the 340 HP engine. By that time I was living in SoCal a mile up from the beach and knew the SWC would likely never see cold weather again. I bought the "FI spacer" from GM which is just a partially machined heat riser valve casting to attach to the manifold and head pipe without the machining for the shaft and valve, and I "ported out" the flat area where the shaft and valve are installed to 2.5" in diameter all the way through.

Duke

[Wally A.]

Re: White smoke from passengers side exhaust

anyone ever mentioned to pressurize your radiator to see if it holds pressure? if it holds 15# , do not worry about it, go from there

[David H.]

Re: White smoke from passengers side exhaust

Wally, this was one of the first things I did quite a while ago. Holds pressure good.

[David H.]

Re: White smoke from passengers side exhaust

Thank you Duke for the excellent description of how the heat riser operates. I believe you may be correct that what I am seeing is condensation burning off. It seems to go away when the engine is warmer. I will do some of the other testing suggested and call it good.
Thank you all for your input.