Bruce,

I just completed this mod on a 1990 13B, normally aspirated engine. When I
compared the original parts with the third generation RX-7 parts, I

noticed

that the bearing surface on the 3rd gen counterweight has a larger

diameter

to accomodate the bearing plate and the bearing.

The 3rd gen Torrington bearing would have run into the lip on the original
front counterweight. How did you manage to do this without machining the
front counterweight?

On the 89 and up models, Just change the counterweight with a third gen
model. They have the same internal ballance.

BruceTurrentine@aol.com wrote:

    The front counterweight has a cast lip that retains the hardened washer
on the OD edge. By machining this lip off, the counterweight now has enough
area to support the Third Gen thrust washer. A .035" washer (radial spacer)
is used to keep the thrust washer centered on the E-shaft. Since the material
that I removed isn't part of the offset mass, it has no effect on the balance
of the counterweight. The selective spacer also has to be machined .035" to
compensate for the radial spacer. Another note is that some 86 engines will
need to have the front stationary gear modified slightly. There are a few
more details to the whole job, but that's the general configuration.
Bruce

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org