nothing like the old detroits to teach you the color chart when it comes to smoke
clear exhaust = proper combustion light to moderate loads
gray exhaust = proper combustion moderate to full rated load
black smoke = overload, insufficient turbo boost, leaking intake loosing boost, incomplete combustion
blue smoke = messed up injector tip, dribbling excess fuel, oil running out of ports with airbox covers off
causes, sometime loose injector body, bad tip/barrel assy, fuel is barely charred, thickened and
remains look like motor oil running out of ports.
white smoke, = over fuel, bad timeing, fuel isn't even charred, partial atomization from some orifices and others just
squirting a crude non atomized shot of fuel that cannot be ignited.
the proof comes out when you are working commission for a living, it doesn't take long to learn from those that came before you
what causes the different colors of smoke, and how best to address them. otherwise you just spend a lot of time from a misdiagnosis
that you don't get paid for. ask me how i know?
ok, you asked
6v53 compressor engine, complete out of frame overhaul, done to factory standards using all factor new and reman parts
rebuild done, broken in properly and send back to its home location 500 miles away
a week later the engine is blowing heavy blue smoke out of one bank
remove air box covers on bank that is smoking, find copious amounts of motor oil pumping up past the rings on center piston
removed head, pan and cylinder kit, disassembled cyl kit, check for broken oil contro rings, all ok, wrist pin snap plug vacuum check
no problems, reassembled and tested, same issue, tear down again, and reassembled, same issue
but more clean oil being pumped out past the rings while the enigne is running. finally check visc against motor oil
found to be heavier than the 40weight engine oil??? hmmm how can that be
same color, but visably heavier
sent injector back to detroit for testing, found to have injector body overtorqued and internals damaged, no fuel control
injector pouring fuel early into cylinder and fuel is fired just enough to thicken to the consistancy of ~50 weight motor oil!
that cost me dearly in lost wages all for a piss poor factor reman injector that sold for 35 bucks exchange.
many times over the years we would have engines such as small cam cummins come in smoking white, and huffing
detach exhaust manifold to determine cylinder, and have a face full of white cold smoke, diesel fuel based.
generally the cause was attributed to a burned valve, bad injector or scorched piston/liner causing insufficient compression
to support ignition at all, resulting in white smoke.
now this is not to say we didn't see some engine's come in smoking white like a freight train with leaking intercoolers allowing water
to go through, but when this was the case it was apparent what the issue was, the telltale sweet smell and resultant sweet aftertaste
on your lips from being around it,
but in all cases it was water that made it through a dead cylinder into a very hot exhaust and flashed to steam.
also it is very difficult to get water into a cylinder of a diesel engine, the compression is quite high so to get there it generally will come in through the intake via a bad intercooler core, not generally through a cracked head or leaking gskt.
that is generally speaking
there are exceptions to every rule of course, you learn very early on to look for the most plausible first and work your way through.
bob g
