After some time pondering this flywheel business over the weekend, I'd
like to challenge the assertion that switching from manual to
automatic flywheel requires a change to the counterweight on  the
engine.

The flywheel I have has clearly been balanced independant of the the
engine.  There are weights welded to the rear face of the flywheel -
presumably to allow it to spin true.  I assume that an automatic
flywheel would be no different.  Given this, I cannot see how the
counterweight -- which is part of the engine assembly -- plays into
this.

In a similar example, the first step of mounting a redrive is to add
the dampener plate to the flywheel.  A dampener plate - I might add -
which greatly changes the inertia of the flywheel & shows itself no
signs of having been balanced (i.e, no weights added).  I find it
difficult to believe that this is somehow different, and does not
require a counterweight change, where the flywheel it is bolted to
'does'.

So -- am I missing something here?  Happy to be proven wrong, but this
is not passing the smell test for me right now.

(Yes, all of this is my desperate attempt to avoid having to fight the
e-shaft nut off)

Mark

No Mark the counter weight is independant from the weight of the
flywheel. Once balanced the engine will run fine with no flywheel.
Only the counter weight is required. However your options are near zero.
If you have Tracy's dampener plate you must have a disc with a ring gear
to bolt it too. The ring gear must be in the right place as well
as the mounting surface for the dampener plate.

You need to start searching for an automatic transmission flywheel
(flex plate) and a rear counter weight. You should then have the engine
rebalanced with the new counter weight, the auto tx flex plate and Tracy's
dampener to be totally correct. Many people don't bother and just get
the right counter weight. You need to talk to Dave Lemon or John at

Mazdatrix

about the correct counter weight to be used with the high compression

rotors

they put in your engine.

There are some light weight flywheels out that that might work however.

Paul Lamar

Mark,
It's like this - you have two counter weights, one at the front and one at
the back.
They work together to balance the engine.

The back one in a manual is the big fat flywheel.

The back one in the Auto, is the second counterweight BUT as Paul says is
bolted to the flexplate ( for proper mounting purposes).
The flexplate is balanced within itself, you might notice a small tab
somewhere.
Therefore the only remaining balancing variable in a particular engine is
the rear counterweight, which is different ( I would suggest) for each
model.

The design of the flex-plate is to accommodate the Auto fluid dampener ( too
heavy for aircraft use), so Tracy has designed his rubber donut designed
damper to fit within the constraints of the availability of light weight and
readily available parts.

Remember that the flexplate is also different for many different models.The
reason for selecting a certain flexplate and starter motor is to give
guidance to the new builder so that he doesn't have to reinvent the wheel.

As Paul says you could use any number of combinations of lightened
flywheels - this is true of starters as well. Including Subaru starters
which match the ring-gear tooth profile. The Mazda specialist shops would
guide you on the selection of counter weight for your particular engine and
fly-wheel or flex-plate selection.

OR you can follow Tracy Crooks guide to set-up for his PSRU.
OR you could totally redevelop the whole thing - however I would advise
against that!

I saw my first Renesis Flexplate yesterday - seems different again!
Hope that helps.
George ( down under)