Paul wrote:

Download the Lemans engine SAE paper Mark. No wear.

Paul Lamar

Mark wrote

Hi Paul, "no wear" may not be what Mazda says in that  paper at all. It says
that "...apex seals, rubbed surfaces of the housings were found to be 1/2 to
1/3 the upper limits of tolerance, indicating remarkable durablity and
reliability"

We don't know if this is 1/2 to 1/3 of the limits, which might be nominal
and thus no wear, or 1/2 to 1/3 wear from the original build condition,
which would indicate an expected wear life of 48-72 hours for this cermet
coated, ceramic sealed marvel (Which would still be remarkable durablity and
reliability for an endurance race car right?).

It sure would be great to get a couple of the Mazda engineers on here.

Interesting titbit, until the end of 2001, 1,094,416 RX-7's had been
produced according to the annual report, but only 2,500/year in 2000/2001.
The cummulative production for rotary engine vehicles is given as 1,800,144.

Mark Wrathall

Yes I exaggerated. The statement is kind of vague. For a 24 hour race 
engine that is still remarkable. Most piston race engines are total junk
after 24 hours. We could could totally destroy a Chevy small block in less than 
2 hours at the 450 HP level. We had to back off the HP a lot to get it
to live for 24 hours.

BTW Iannetti claims no wear on ceramic apex seals. The life of a gen set 
engine using ceramic seals has been projected to 25,000 hours. Nobody has run
one that long yet.

Paul Lamar
 
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