>>I believe that Atkins uses the crankcase oil, not sure what type of
oil
though.<<

I've had multiple conversations with David about oil injection... and
yes, his
RV installation includes the stock oil injection system, and I believe
he uses
Amsoil.  Last time we spoke Dave advised me that the oil injection
system
really doesn't "inject" the oil in the sense that it enters the
combustion
chamber as a mist or stream, rather that it causes a droplet of the oil
to
emerge from the injection port and then be wiped away by the apex seal.
FWIW.

I've had my disagreements with Dave Atkins, but when it comes to hands
on experience with these engines (racing, flying and otherwise), you'd
be had pressed to find someone with more (well; maybe Leon, but I don't
know his experience).  I'll accept his word that carbon buildup problems
mainly occur in cars where cheap oil is used, and/or not changed
regularly.  His experience shows that injecting engine oil using high
quality synthetic (Amsoil) with our duty cycle es no problema.

Al