> > > 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)
> > >
> > >
> > Hi George,
> > Balancing weights of rotors are done dry not wet. Mazda Factory

balances

> > rotors to within 4 grams of each rotor. Balancing is done with the e

shaft

> > turned at 2000 rpm. Dennis Hayes and I talked at length about the

process.

> I
> > believe him as he is very knowledgeable but Hayes does not do

balancing

> > either. They farm out the balancing as that is how I found out about

it.

> They
> > lost my parts and it took four months to get the ones they did not

loose.

> I
> > was very impressed by Dennis on the phone the first couple

conversations

> > but after doing business with empty promises, I can not recommend any

of

> > my fellow rotorheads to use their services. I wish Dennis would go

back to

> > trying to be small. Their work ethic would drastically improve. I hope

you

> read
> > this Dennis. Anyway I will gladly share anymore info I have with

anyone.

> > Doug Mueller
> > RX-6 13BT
> > N900DM
> > Boulder City, NV
>
> Doug,
> I don't wish to get you offside here, but I think you misunderstood my
> message.
>
> TRUE rotors are balanced dry when balancing the rotor within itself and

this

> should be a separate step before balancing the whole assembly, 4 grams

is

> easily attainable in this particular process as there are no fluids
> involved.
>
> HOWEVER the assembly MUST be balanced including the oil weight that the
> rotor holds, as this is the additional weight ( with other things) which
> represents the total rotor weight. IT is terribly important that you
> understand this aspect when talking about balancing a rotary engine, OK!
> George ( down under)
>
Hi George, I guess I did misunderstand, I do agree with you regarding the

balancing

of the whole assembly. It is important to have having matching weight

rotors. Ie same

year and model rotors. I only disagree on the balancing of the whole

assembly because

of the process I have seen it done. I am repeating the process that was

explained to

me. A counter balance is weighed and balanced with a dry assembly. The

additional

weight of oil is negligible and the counterbalance is not compensated

foradditional

oil weight.
Although adding oil does add minimal weight the rotor does not retain the

oil. That

is constantly flowing out and being replaced with fresh cool oil to help

keep the

rotors cool. The counterbalance and the entire assebly is balanced dry. I

have

pictures somewhere of this process.
Respectfully,
Doug Mueller

Doug,
If you adviser tells you this it goes against the advise of all the experts
that balance Rotaries.
I take hart that Hayes send out their engines for balance.

The rotors are indeed FULL of oil when in the engine, they do have their oil
replenished via e-shaft jet. Only when the rotor is full does the oil
dribble onto the stationary gear ( the other side).
See Photo's attached.
Now only when the individual rotor volume ( weight) has been established can
the assembly be truly balanced ( DRY).

It may be that they don't disclose this step to everyone or Hayes don't even
know it's part of the process. Engine balancers do keep their secrets -
believe me when I say it has to be done.

I do hope you appreciate the insight into this process, it's very important
to understand the steps. For instance if you were to have the engine
balanced  by an engine balancer who normally didn't understand this
process - it wouldn't turn out too good. Even if the balancer were to use
ONE single volume weight, it won't turn out so good. Every series and
different compression rotors have different volumes, therefore different
weights.

The next step is, what else is added to this volume weight for balancing
purposes, side seals, corner seals etc.
George ( down under)

Do me a favor George and fill the rotor with oil. Measure how much
it takes and divide by four.

This is an illustration from K. Yamamoto's book Rotary Engine
1981 edition published by Mazda  of how much oil is in the rotor
at any given moment. It changes degree by degree as the e-shaft revolves.
It is impossible to perfectly balance the engine by loading a
quantity of oil in the rotor.

Paul Lamar


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