<VV> carbon buildup

[Frank DuVal]

I can decarbon a motor with water. It sort of steam cleans the carbon 
from the combustion chamber. On a Corvair you do one head at a time. I 
have done this many times over the years on many engines.

Here is a how to do it clipped from a webpage out in the etherland:

***If* you really want to clean the carbon out of your engine follow 
these simple steps. Fill an empty soda bottle with water. Remove your 
air cleaner. Start your engine. While using one hand to control the 
throttle, trickle the water into the carb or throttle body with the 
other while holding your thumb over the bottle opening. Keep the engine 
rpm's up so that the engine doesn't die. *Make sure that you don't pour 
the water in too fast! Water doesn't compress and if you pour too much 
water in, severe engine damage can result!* White smoke from the exhaust 
is normal. If you have a port fuel injected car, you obviously won't be 
able to use this method, but I have had success with connecting a vacuum 
hose to a port at the base of the throttle body and sticking the other 
end of the hose into the bottle of water. The vacuum of the engine will 
suck the water in, creating the same effect. This will clean out even 
the most stubborn carbon, by 'steam cleaning' your cylinders.

GM also sells Top Engine Cleaner in pour and aerosol cans. TEC you add 
while the engine is running, let it stall and soak overnight if possible.

 From the teaching old dogs new tricks department, if you do this 
"steam" cleaning just before tearing an engine down, the pistons and 
heads will be cleaner to rebuild!

Frank Duval