clare at snyder dot ontario dot canada wrote in message
...
On Sat, 12 Apr 2008 19:08:43 -0400, "Ed Huntress"
wrote:


"RoyJ" wrote in message
...
After reading the other comments I think you have multiple issues going
on
to switch from diesel to gasoline:
-the gasoline will have a MUCH lower viscosity, you are going to get way
different (more)amounts of fuel through the injector. I'd think that is
what causes the white smoke a lousy performance, it's too rich.
-at the same time, gasoline has lower fuel value per gallon or
milliliter,
same volume of fuel will cause the engine to go lean, never a good thing

You raise an intriguing question there, Roy. How do you make a diesel run
lean? g

-gasoline has a much higher flame front speed, ie it will detonate,
really
does bad things to the top of the piston.

It will detonate, but it's because of the *slower* flame front speed.
That's
the thing that's indirectly measured by the cetane rating: gasoline around
25, diesel typically 45+.


It's not realy detonation, and it's not really the speed of the burn
that is involved (flame front). It is the speed at which the cyl
pressure goes up with gas vs diesel. You DO get a faster pressure
spike when burning gasoline than when burning deisel at high cyl
pressures.

Reference? You may be comparing a homogeneous mixture in a spark-ignition
engine with the timed spray in a diesel. If you create a homogeneous mixture
with diesel alone, it burns faster than gasoline. That's what the
HCCI-engine research shows.

--
Ed Huntress