full balancing of e shaft rotors and counterweights assembled

[Grizzly]

I don\'t belive it, I\'ve just been looking at mine, They are all well covered in grease but on one there is faint outlines of what look like dowls?? but they have been Machined down. I\'ve never noticed this before??

I\'ll have to take one to work and weigh it too see exactly how much they have been Played with? I\'ll have a Go at getting a Picture of it too but its not very Clear.

Do you think this could have been the Fixing for the ballance or do you think there could be Internal Work? (they don\'t look like Bolts)

[Timrxmotors]

PS ,
have you done snap rings in the rotors gear ring( lock up the gears to stop its walk out at high rev)

Has anyone actually seen the gears \'walk out\'at high rpm? appears to be a myth which doesn\'t apply to modern rotors.Mine have never moved,I have logged 12,600 rpm and probably been higher.

[stuart wizy]

Has anyone actually seen the gears \'walk out\'at high rpm? appears to be a myth which doesn\'t apply to modern rotors.Mine have never moved,I have logged 12,600 rpm and probably been higher.

To walk out, every thread on all the grub screws would need to be ripped out,
have u balanced your e shaft with everything on tim?
12,600rpm is seriously quick, I knew u where reving high by the sound of your motor at elvington but i didnt think to nearly 13 k!
I can balance the assembly myself between centres the oldschool way by just turning the whole thing in different positions and letting go, if it drops and stops, mark the bottom with a pen and add weight to the opposite  side until it wont rotate in any position on its own. this is how we balance grinding wheels on all the large grinding machines that spin really quick.
This guy in manchester can do it on a dyamic balancing machine the same way they balance turbo shafts, its got an encoder on the end linked up to the shaft so it knows what angular position its at all the time and  knows how many grams are being thrown out at that excact angle, thus remove weight at that angle, but how the hell  u keep the rotors on when it spins up to high revs I dont know.

[shaunwil]

could you not machine some sleaves that are in 4 peices and balanced on a mandrel prior to fitting? this could be used to shim the rotors into position so when your doing the full balance the rotors don\'t move. would need it be tight to the eshaft as well but it should cancel itself out of the overall balance.

Shaun

[stuart wizy]

Here is a pic of a Assembly being Ballanced. (this is manderville\'s ballancing set up)

ive sussed it out,
im gona turn 2 spacers the same outside diamater as the 3 tip points of the rotors, the inside (bore) diamater bigger than bore of rotor bearing, drill amd tap the spacers in 3 places at the centres of the corner seal bores on your rotors.
now this spacer will fit on 1 face of the rotor with long allen bolts turned down in the middle to 2.8mm dia so they fit through the 3mm wide tip grooves but leaving the thread on the end to screw into the spacers with large washers on the oposite side.

measure the weight of the rotor empty then fill with oil and measure weight,
weigh the 3 allen screws and washers, turn down one side of the spacer until it weighs the same as your oil weight and clamp up and balance.
that would let you  balance everything perfect with the rotors full of oil without guessing because the spacers are on the centre line of the rotors lined up with 3 tip points. (same rotating axis as the oil would be)

[Grizzly]

How would you go about the Timing of the Rotor spining on the E-shaft? or would that not realy matter as long as the Rotors weigh the wame?

[stuart wizy]

thats what them allen bolts are holding on the rotors on your pic griz, its the only way to get the oil weight, the rotors will be free to spin in what angular position they want when rotated quick, they find there own balance if you think about it.
very dificult to rig up so they spin timing wise on the gears though without assebling stationary gears fixed somehow, theyve not done it on that pic anyway!
By the way have u seen how much racing beat charge for lightening the rotors and counterweights assembled by the way?!!!!!!!!!!:Thumbsup!

[Grizzly]

Yep... BIG BUCKS!!!!!!!!!!!!!

Not as bad as some of the other Performance shops in the US i\'m sure they send out the RB and wack there bit on.

For some odd reason AUS/NZ seems to be the best value for money, Prices seem quite good (just Shippings Bad)

[Shyne]

For tight tolerance rotor configs, you can get a 2 piece E-shaft. benefits: it will already be balanced (although do balance the complete rotating assembly!) and it will be stronger(allowing for tighter tolerances).

a point to hold consideration for is torque resulting from rotating mass, without weight, you will have affected torque figures. Obviously, the revs are the key result of this process, which in an N/A applications is very usefull, but a charged drag application could benefit from greater low end torque.

I am glad people are now looking into/doing this though. Progress for the UK community

[Grizzly]

For tight tolerance rotor configs, you can get a 2 piece E-shaft. benefits: it will already be balanced (although do balance the complete rotating assembly!) and it will be stronger(allowing for tighter tolerances).

yep you got it, If you buy a 2pc crank they are usaly Ballanced for use with stock Rotors etc and i know my 3pc E-shaft came with Counterweights and the Rotors where done by Some one else and sent there for the whole lot of be ballanced. But thing is the Roller bearings have a reputation of Failing on High RPM/HP motors (some thing to do with Metal to metal wear as opossed to Plain bearings that sit of a Film of Oil)

If you think about it the engines are mass produced so they won\'t be Ballanced as an assembly rather matched and roughly Ballanced by weight. Acording to people that have not removed weight and just ballanced the Motor (13b\'s) they say the car feels smoother but for the effort involved its not that bigger deal.

The more i look into it the more i think there is a point in a Rotay where there is a Ballance between power and RPM if you have Big Power you can\'t run big RPm but if you have Lower Power high RPM can be achived.

[stuart wizy]

totaly agree with the 2 piece central bearing shaft, no deflection , fully suported, no chatter or vibration at high rpm.
Ive looked at the ausy one from guru with the central bearing,a bit expensive me thinks at this stage,
im gona balance mine with the lighter rotors, use 3mm atkins and get racing.
regarding torque and power with different weighted rotating assemblys, dont forget mine is fully bridge ported so the power curve is at high rpm and climbs like a cliff face above 6,000rpm or so ive been told ,so it needs to rev as freely as possible with least amount of vibration in my opinion.
If i wanted big torque Id go yank.

[Timrxmotors]

My 12A has never been balanced,12A rotors with a 13B rear counterweight.You will know as soon as you start the engine if it is far out.I did find a company called \'Vibration Free\' who would have no problem balancing a rotor assembly.

[RotorHeid]

knowing about rotors balancing but cannot put my word into writing,it\'s better to hear from the horse\'s mouth live than reading in this forum.
Its won\'t walk out at 1/4 mile down the strip but long race e.g 6hrs,12hrs etccc.., its will walk and jam the housing etc...
This country is UK, don\'t race the rotary car until fast and the furious film came out. so little knowlege what we got about seize-up!

In the pic, no rotors in the balancing machine, only bobweights,e shaft and counter weight!!

Tim, rev your engine to 11,000rpm until it\'s seize-up,using your timing watch and I bet it\'s 1hrs,39 sec!:Thumbs-up

And mine 13Bbp with  rear 12A counter weight

[stuart wizy]

knowing about rotors balancing but cannot put my word into writing,it\'s better to hear from the horse\'s mouth live than reading in this forum.
Its won\'t walk out at 1/4 mile down the strip but long race e.g 6hrs,12hrs etccc.., its will walk and jam the housing etc...
This country is UK, don\'t race the rotary car until fast and the furious film came out. so little knowlege what we got about seize-up!

In the pic, no rotors in the balancing machine, only bobweights,e shaft and counter weight!!

Tim, rev your engine to 11,000rpm until it\'s seize-up,using your timing watch and I bet it\'s 1hrs,39 sec!:Thumbs-up

And mine 13Bbp with  rear 12A counter weight

ian there 3 very large bob weights on the e shaft dont u think!!:Giggle
do u know how to balance a fully assembled e shaft then??

[RotorHeid]

Yes, its for 20B
bobweights must be the same as the weight of the rotor e.g rotor with all seals, bearing and weight of the oil etcccc.
13B rotor\'s Bob/weight\'s weight =4920grams
12A = 4260 grams
20B =3750 grams
The max rev of the balance is 720
drill out at counter weights only to balance it( see counter weight pic)
understand it okay!  
got all  info from Mazdaspeeddeveloment webset.:Thumbsup!