I've been using Castrol 20-50 in my 20B, with the metering pump injection.
The exhaust goes through the prop.  Based on the gummy/sticky film that
builds up on the prop; it seems to me that the oil must not be burning very
well.  I'm thinking I either need to change type of oil, or dis the OMP and
go to premix.

Since the Idemitsu racing oils are made especially for rotaries; do you
suppose that clean burning is also one of their qualities?

Al

I think so. I have been using it in my RX8. Besides that, the girls
they hire in Japan are cute :)

-- 
Paul Lamar ...No rotor no motor.

Whether you use premix or just feed the OMP from a bottle of 2-cycle oil --
select a synthetic 2-cycle oil that carries ISO-L-EGD or JASO FD (best),
ISO-L-EGC or JASO FC (better) or API TC.  These will give you the absolute
lowest amount of smoke, carbon, and seal sticking.  Petroleum and
synth-blend 2-cycle oils can't meet ISO-L-EGD or JASO FD...

As for the engine oil...

I don't recommend running automobile engine oil in our airborne rotaries
that lists 'fuel saving'.  I also don't recommend using products that are
rated as API SJ, SL, or SM; or ILSAC GF-3 or GF-4.

Auto engine oils are evolving to include friction modifiers to help increase
fuel economy.  These modifiers are often the first parts of the additive
package (along with viscosity improvers) that are sheared (physically cut)
in service.  Our engines include gears in both the engine and reduction
drives that are hard on oil.  The 'mangled' friction modifiers tend to
become deposits.

These later oils are also increasingly limited in phosphorus, zinc, and
sulfur.  The industry has opted for chemical limits to minimize
contamination of emission control devices.  The primary compound containing
all three is the multi-function additive package responsible for wear
protection, acid neutralization, and detergency.  Chemical limits required
for newer oils are putting more stress on engine cleanliness and wear
control.

Instead of using auto engine oil in our engines, I highly recommend
selecting a synthetic 10W-40 or 20W-50 motorcycle engine oil.

Why?  Motorcycle (M/C) engines (compared to auto engines) are higher speed,
higher compression, about twice the power/weight, variable cooling, long
periods of inactivity, and most use the engine oil to lubricate the
transmission.  Sound familiar?  These oils have to protect the engine and
transmission both in service and from rust when inactive, must stay
in-grade, and handle some level of fuel dilution, and must protect the wet
clutches (no friction modifiers) - in a significantly higher stress
environment than an auto engine.  And they do it with much less oil in the
sump.

Second best would be the US heavy-duty diesel engine oils (HDEO) referenced
on this BMW Motorcycle service bulletin. U.S. HDEO up thru API CI-4+ have
very strong additive packages to control wear and keep the engine clean in
high-soot environments.  Chemical limits haven't come into the HDEO market
until the latest CJ-4 spec for 2007 on-road diesel vehicles with catalytic
converters and catalytic diesel particulate filters/traps.

Andy Hecker
Lube tech/fleet lube sales
Working on STLE/CLS certification
RV-9 parts have arrived :-)

It is a good idea in general to use one type for the apex seals
and another type for the engine and gear box. The best oil for the job.
I have been using Mobile One in my rotaries prior to the advent
of Idemitsu with no problems. I also have used it in
my piston engine cars for close to 300,000 miles. Everything
else in the Dodge Caravan had failed except the engine :)
After 300,000 miles and 12 years the engine still passed Ca smog inspection.

In my rotary aircraft I would use 2 cyle oil for the apex seals and
Idemitsu for the engine. If you don't want to premix Richard Sohn
has a device that will feed the apex oil metering pump just 2 cycle oil
from an aux tank.

The rotary is unique in that it has no high load, sliding line contact wear surfaces such
as cam shafts and gears. The rotary has phasing gears but they do not appear
to be highly loaded as they never need replacing. It is also unique in that the apex
seals never change direction unlike piston rings. The other obvious differences are
the highly loaded rotor bearing at 9,000 E-shaft RPM while the rotor is only rotating at
3,000 RPM. In fact the rotor bearing load is the limiting RPM factor in the rotary
and not the catastrophic failure of a reciprocating part. Not an issue however
in our aircraft engines that rotate at a maximum of 7500 RPM. For these reasons
it makes sense to formulate an oil specifically for the rotary. Hence Idemitsu.

As far as I can tell many wear packages in engine oils are designed to address
the sliding line contact cam shaft and gear wear issue during start up and afterwards.
So far as I know nobody has worn out the Ford auto TX gears out in a Ross or Tracy gear box
yet, providing the box was machined properly. These gears are so cheap that replacing
them every 500 or 1000 hours is no economic burden anyway. Less than $200.

So Andy, if one is using two oils, what do you recommend for apex seal oil?
-- 
Paul Lamar ...No rotor no motor.

Andy,
Good analysis! My new 1800 Suzuki is a high compression MC and after initial
wear-in with a good quality mineral oil, they switch to a synthetic blend.
Advice to me that full synthetic is wasted in anything other than racing
application.
So what's regarded as a synthetic blend i.e. what is in this type of oil.
George ( down under)


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