Agreed we probably don't need the additives that have been optimized for the
camshaft (although the apex seal lubrication regime is similar -- highly
loaded sliding line contact -- but you're not intending to use the turbine
oil there anyway). The crankcase oil is what lubricates the oil seals (and to
a smaller extent, the side seals). Since the side housings are iron, they
could possibly benefit from some of the anti-wear additives specifically
designed to form boundary lubrication films on ferrous substrates (the oil
seal and side seal conditions may be similar to piston ring conditions).

You should be able to obtain a data sheet on the oil from the maker. It
should list the viscocity at various temperatures.

Are there any synthetic oils designed for aircraft piston engines? They might
also be worth a look, as the viscosity should be better.

As somebody pointed out Mobil withdrew AV synthetic after some AC engines
were damaged but I know not the reason. I suspect that synthetic does not
stick to surfaces for very long. When I use it in my Ford V8 and I don't
drive it for awhile I think I hear tappet noise. I could be way wrong on
this.
 

The issue of bearing fatigue concerns me the most. When a bearing fatigues,
chunks and flakes of bearing material begin to separate from the bearing
backing quite suddenly. The oil pressure degradation will not be so gradual.

Jon Lauter
Rotary Power Marine Corporation
www.rotarymarine.com

BTW Jon have you heard of anyone using three stock springs under the apex seals?
Two long ones and one short one. This engine I have was rebuilt by some one
that did that. Dave Lemon (Mazdatrix) mentioned he would be worried about
stack height. There is some slight evidence of chatter and a limited amount
of apex seal lube spread from the oil injector holes. Nothing serious yet
but the overhaul is only two years old. I have no intention of putting them
back in that way.

Paul Lamar
 
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