BoatBanter.com - View Single Post - Diesel engine smokes after many hours of very light load

wrote in
oups.com:

I know I'm not supposed to run diesel engines almost at idle but I had
no other choice.

Why's that? Where do these wives tales come from. Go by the local
railroad yard. Their diesels sit there at 100 rpm for days with only
intermittent yard work where they run them way up to....oh, 250 RPM!, but
only to move some cars around....(c; I know of one yard engine that has
the date 1947 on it!

I'm more worried about the "white smoke". Black smoke is NORMAL...N-O-R-M-
A-L! Soot is normal anytime you increase injection before the engine RPM
comes up to provide the air to explode it. Excess fuel with not-enough-air
and voila...soot...carbon...HARMLESS! White smoke, on the other hand, may
be STEAM from some crack or leak in a cylinder head, liner or head
gasket...not good. White smoke also happens when lube oil leaks into the
cylinder which boils off because it's too thick to completely burn. Lube
oil is as bad or worse than coolant. Diesel engines can RUN AWAY burning
lube oil from the sump....and explode! Really not good. You have to see
it to believe it! Standing in the engine room of a wooden minesweeper
watching a 12-cylinder Packard diesel running away is even more
exciting....it came in through the supercharger leaking.

Black smoke, and the huge cloud of soot that comes from the exhaust
clearing its throat as you accelerate away from weeks at idel is good.....

White smoke is BAD....except when the engine is cold, then it's normal
(incomplete combustion in a cold diesel. Watch some trucker start his on a
winter morning...(c

One of the fun things of owning an old diesel Mercedes is when there's that
nice white Cadillac tailgating right behind your bumper. You stomp it to
the floor, flooding the cylinders with a big spray of fuel, let it all the
way off then stomp it again. The soot wafting over the hood of the Caddy
being sucked into the air inlets and any open windows.....PRICELESS...(c;