On Thu, 23 Aug 2007 21:15:47 -0700, "Calif Bill"
wrote:

2 stroke diesels will run without a blower. I have a model airplane engine
diesel that jsut uses the crankcase like a gas rig. And there were a lot of
those 1 lunger diesels in Montereys, etc, that did not have a blower.

Right - but how did that model engine lubricate the main and rod
bearings, and the wrist pins and piston bores? If they were misting
the fuel into the crankcase as a bearing lubricant before it got
inducted and burned as the fuel, that isn't a true Diesel engine, it's
a modified Glow-Plug engine.

And how did they get the crankcase pumping effect to work on a
multi-cylinder engine where one piston is going down when the next is
going up? The glow-plug engine would need solid dividers between the
crankcase sections so each piston pumps for itself.

The Detroits have an open crankcase, so no pump effect. And they
use conventional pressure oil lubrication, plus most diesels have an
oil jet aimed at the underside of the piston for cooling and wrist pin
lube - not sure, but Detroits have to do it like everyone else... If
any of that motor oil in the crankcase was to accidentally get into
the cylinder intake air, you have a runaway engine.

Same thing if an oil seal on the blower or the Turbocharger (if
equipped) blows and starts dumping motor oil into the intake - a
runaway engine that will soon "Go Splodey" when it exceeds redline by
a sufficient amount.

This is why they have that Emergency Shutdown air damper on the air
intake, that's the only way to kill a diesel engine if the oil it is
running on isn't coming in through the fuel injectors.

-- Bruce --