Folks I would like to offer this info because it is important. The

flexplate

necessary comes out of an 86-88 13B NA. It has the wings on it as

discribed on

the previous email pictures.
The counter wieght can be interchangeable with other engine types of older
models or turbo versions of the motor ie. 13B Turbo. but you must heed the
differnet weights in the rotors. In order to facilitate Tracy's redrive

you will

need to first identify what motor you have with the compression ratio.

That will

tell you approx. weight of rotors. Then you will need to order a

counterweight

for your engine not for the flexplate. This will keep your balance. If you

find

a counterweight at the junk yard you will need to take the whole assembly

and

have it balanced. The parts needed to balance will be the

e-shaft,rotors,and fwd

and rear counterweights. For an even better balance job you will send in

the

front hub and the flexplate to. Pineapple racing will balance it all for

you as

well as Hayes Rotary. The job costs about $450 to do it but it is worth

it. I

would recommend anyplace else over Hayes as I had great difficulty with

turn

around time with them.
Intersting note is that even two identical engines will have different

weight

counterweight weights. Mazda Fasctory racing balances to within a gram but

they

have told me that several grams difference between rotors and

counterweights are

common.

I hope this helps. This is an old topic that was discussed about 3 years

ago in

the archives. If you want more info on it. I did  a lot of research on

this.

Respectfully,
Doug Mueller
RX-6 13BT
N900DM
Boulder City, Nevada

Doug,
Good information and advice, there are some things I don't totally agree
with however.

Firstly I doubt that Hayes Rotary balance to a gram - if they do that would
be wonderful, but having tried to do that, I fully understand the problems
associated.

Firstly it's not just the weight of the rotor which is in question but also
the weight of the oil in the rotor. As there are many different rotors,
their cavities ( see oil volume = weight) vary accordingly.

Then do they measure the cavity (oil weight) statically or dynamically.
A great deal of difference can be seen using the different methods.

Do they use oil or water or soluble oil ( machine coolant -oil in water) and
what conversation ratio do they use.

Did you ever measure a gram of water oil or coolant ?- it ain't much!

I figure if they got within an ounce there doing well - but a gram, I doubt
it!

Then there the argument about what parts are included in the balancing and
how (and where) the parts are held in place when balanced.

Then there's the different balancing machines and which is best for the
purpose in relation to rotaries. Generally agreed the belt type is best for
rotaries
.
I figure I can get to within half an ounce, but never a gram. I figure just
to wet the inside of the rotor would take an ounce or more.

If they don't take everyone of these variations into consideration their
just BS .ing. However it does sound good to the un-initiated!

BTW 1 ounce = 28.3495231 Grams.

George ( down under- working hard on my single rotor)