David Carter wrote:

Thanks Tracy and Len, for fleshing out our understanding of the Mikuni
oil metering pump.  Only thing we don't know, now, is whether or not it
has been modified from "gravity feed" to "accepting engine oil galley
pressure".  I suspect someone will dig that out shortly.  Otherwise,
we'll have to find out - and if it makes any difference either way.

It would be easy to simply say, "With my modern fuel flow/totalizer
system, I know exactly how many gallons of gas I'm going to pump into
the aircraft at this fuel stop.  Since I manage my fuel like I did in
Cessna 172, i.e., alternate between left and right tanks in climb and
cruise, and run one dry (if I go that far), I know how many gallons I'm
going to pump into each tank.  Therefore I need that many fluid ozs (or
twice that) of two stroke oil in each tank.  Just get it out of my tied
down sack in baggage compartment and do it."

However, we are still "proving" the use of 13Bs in aircraft:  We have
too small a sample population, too much variation in conditions of
operation (ranging from conservative low power to racing), and too few
teardowns after significant hours - thus can't yet draw significant
conclusions about longevity of the engine and effects of oil "injection"
vs "premixing" oil with fuel.

I am not a slave to "how the factory did it", because that was skewed
from "best practice" by "emissions" and "driving public acceptance"
issues.  However, the fact that Mazda increased injection rate at higher
throttle settings makes me hesitant to accept that we have "two equally
satisfactory solutions to apex seal lub and cooling, therefore I can
choose the mechanically simpler of the two and just pre-mix oil with
fuel." (Paul Lamar and Todd Carrico's observations).

So, maybe just to give future home builders and 13B users another data
point, I plan to keep the metering pump and not pre-mix.  For all the
reasons just posted, I won't meter "crankcase oil" due to bad effects on
apex seal (up to and including zero compression when seal sticks and no
longer seals).

So, now I understand (from Tracy & Len Louthan) that the Mikuni metering
pump is geared to the inside guts of the engine, and it's shaft may need
lub and also has a seal at the crankcase.  I understand, hazily, that
the metering pump is hooked to the throttle linkage - that is what
increases the injection rate as power is increased, no?

Working from that, now all I need to know is the flow path for engine
oil into the metering pump so I can plug that path "out" of the engine
(plug in both engine case and metering pump) and then, if possible,
create a new path from the external gravity feed tank into the metering
pump's existing (but plugged at the case) oil galley:  Where would I
drill - and how deep to enter that input passage?  Location must provide
adequate thread depth for line fitting from external tank and be
accessable for tighting/removal/replacement when pump is installed.  If
metering pump's case is aluminum, then use helicoil or equivalent steel
threads.

David Carter

What you are overlooking David is the difficulty of separating
the pump from it simeze twin... the front cover.

Here is a drawing. It would be easier to machine your own
simple gear displacment type. Sealing the intake and providing
shaft bearings and seals is going to be a big problem
and for what? This is not a car engine. It does not spend
a lot of time idleing around town. 

IMHO The rotary makes a great aircraft engine. 
It also makes a lousy car engine because of smog and high low power 
fuel consumption. Besides that it is *** TOO *** durable for a
car engine and therefore cost too much to make.

Paul Lamar
 
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