I've heard from many car people that premix works very
well without worry about the oil settling out of the
fuel.  I don't know how often they were driving the
cars, though, which could be a factor.  Clearly, if
you're autocrossing the car every weekend, it'll mix
the oil up nicely after just a few corners.  I haven't
heard anyone talk about having premature engine
trouble because of premix.

On the other side of the coin, I've seen countless
dirtbike engines that had seized pistons and a handful
of oil-fouled spark plugs from the last ride.  They'd
poured premix into the tank and then let the bike sit
for several weeks, and the oil settled out.  They were
running way too much oil off the bottom of the tank
(thus the fouled plugs) and once they got through the
oil, it ran like a raped ape...  for about 5 minutes,
until it seized due to lack of lubrication.

If it was me, I might adapt the Mazda oil metering
pump to draw from a reservoir of two-stroke oil rather
than the crankcase.  Then you get the cleaner burn of
two-stroke and don't have to worry about depleting the
oil supply in the crankcase; also, you don't have to
worry about oil settling out of the fuel (I don't know
if it happens enough to be a problem, but it's easy
enough to eliminate any worries about it by using the OMP).

Adam Wade


The next message should be interesting :)

Paul Lamar ...No rotor no motor

Adam,
I'm not sure if Paul was anticipating a reply form Me or had another
post to which he was refering. As an FYI though, I'm a long time
motorcyclist and constructor. I have done 2-stroke engine work for
Kenny Roberts. I worked for Kawasaki in the 70's. What I was refering
to, and I believe was confirmed by the fact that they are adding bio-diesel
to the Ethanol is that there is a lubricity problem. I have worked on
several
2-cycle kart engines running METHANOL, which though originally drawn
from a petroleum stock has trouble with oil separation and works best
with some of the castor-based oils, or current synthetics designed for
alchohol fuels. I have considerable experience, but not with Ethanol. If we
do have a chemist monitioring the list perhaps he or she can provide us
with non anecdotal information as to wether oil will stay in solution in
ethanol. Doug, I don't think you could forgo the mix oil just because there
is bio-diesel in the mix either. The bio-diesel probably only brings the
lubricity back near to that of gasoline. I'm not trying to knock E85 but
with any new addition or change we must cover all possibilities. For
operation in a piston engine with best power we would raise the
compression ratio at least 2 points when running on methanol. Typically
the ratio would be around 14:1, gasoline gets close to compression ignition
that high, so the setup for the different fuels would vary a lot.
Bill Jepson

Bill,

Thanks for the heads up on the lubricity issue with AGE 85. In light of what
you said it would be prudent for me to premix two cycle oil, especially
since I will be going with the 10:1 Renesis rotors. One point I would
appreciate your opinion on.  I am considering having the two or three
injectors per rotor.

I want to place an injector (probably the primary for better idling) in the
location of the oil metering hole and the secondary injectors shooting
through the P port after the slide throttle.

Because of the size of the hole needed to provide a spray directly into the
chamber won't that hole volume lower the compression ratio?  Ditto a third
spark plug?

Thanks

Doug



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