Put this in your pipe and smoke it

[John Hofstetter <hofs@domain.elided>]

>Subject: White smoke
>
>OK, for the year I drove my '72, it would always give me some white smoke on
>start-up, then go away.
>
>Last night, I had the Scout running to do some carb tuning (power valve
>probably isn't blown, but mis-adjusted (according to the local Champion
>guys).. so I was going to tinker with it... 
>
>The whole time, white smoke came from the tailpipe.. even with the choke in,
>and the truck warmed up.
>
>Is this something that should go away with some more use?  something that is
>just annoying but not damaging?  Something that I should probably remedy
>before doing the engine swap?
>
>A friend suggested the rings have dried up from non-use, and shrank some,
>causing an imperfect seal...
>
>What should I do?...
>
>1972 Scout II, original 304A, 63k miles
>
>- -Tom Mandera, Helena MT

Tom, 
As a rule of thumb, blue smoke means excessive oil is being burned, black 
smoke means too much gas is attempting to be burned, and white smoke 
means that water in the cylinders is being turned to steam. I am pretty 
sure that you must be getting water into the cylinders, hopefully from a 
bad head gasket. Take off the radiator cap and look for gas bubbles 
coming up through the coolant. Do a compression check although I doubt if 
this would always show the leak. Radiator shop guys can test the gases 
coming out of the radiator to see if it is combustion gas. 
Usually, I would think, if water can get in, combustion gas can get out. 
The water mostly seeps in while the engine is not running and the gas 
gets out when it is being compressed.
John H.