Looks like we got a contest going here. Who can make the
longest claim for engine life. A Russian radial piston engine
or a Mazda rotary? :-)>
My money is on the rotary.

http://www.powercold.com/PR/20010627.htm

Paul Lamar

The key here is the difference between could? and has!!

I really believe that though a rotary is much less likely to

blow, but will wear out faster than a piston engine. The

rubbing velocites are the same or higher, and the wear

surface loads are higher. Industrial gas piston engines

have life measured in years - Vance

Not true. Nobody yet has worn out a set of ceramic apex seals.
Ceramic piston rings won't work as piston rings need to act as a spring.
The ceramic apex seal has a separate spring.

In addition the seal does not come to a complete stop at the top
and the bottom of the bore and then change sliding direction as in 
a piston engine. This is why you get a groove worn in the top of the cylinder.
This is the major problem with piston rings.

Problems with piston rings in engines are very very common.

Course we have not even mentioned silly exhaust valves running cherry
red at the limit of their existence jerked off the seat and
slammed back down by a strong spring every two revs.

Industrial gas piston engines run at a very low duty cycle hence
the power to weight ratio is in an entirely different category
than a Mazda rotary. If you run any engine slow enough it will run
for thousands and thousands of hours. If you run the two engines
at the same seal sliding speed the rotary will still be much smaller
and lighter for the same or more HP. Course the rotary apex seal is
not stopping and starting up in the opposite direction so even this
is not fair to a piston engine.

Ceramic apex seals were not available for the Ingersol Rand engines
at the time yet they ran 40,000 hours with no problems.

Face it Vance! Roundy round beats jerking back and fourth :-)>

Paul Lamar
 
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