fcdrifter13

Ok today at work we pretty much had the day off so I had my friend bring me back to the house and grab some engine parts. For those who odnt know I work at a engine machine shop. Well considering most of my stuff is about useless, I figures I would try balancing the rotating assembly including the flywheel. Well I had it all put up like it suppost to be run on the machine for balancing. I started up the machine and it appears that the stock parts from the factory are way out of balance. I tried it with and without the flywheel. And yes I did have the counter wieghts on.

Ok so my first question is what would be the best way to balance out the assembly. Taking wieght off of the rotors to make them the same wieght. But then I would come to the issue of the counter wieghts. How would I go about changing there wieght to balance things out.

Now you are probably thinking well if you work at a machine shop you should know how to do this. instead of just rauuning the e-shaft i put on the rotors and countershafts and gave them a whirl on the machine. Now most of the time we just run the crank on the balancer and then make all of the rods and pistons the same wieght.

So has anyone tried this. And what were your experinces. Am I going about this in the right way. Like I said noone at the shop has tried to balance a rotory so were basically just trying different methods. Also the equipment is a little old we dont have anything that is computer controlled. Thanks for your help.

Now for my run of who will be the one with the best answer. Hmmm Im thinking either ted or Icemark may have the answer hidden away somewhere.

FirstRotaryExp

iTrader: (3)

Well a good idea would be to acquire matching rotors. THey are stamped, i forget where atm, with letter designations. If you get a matching letter pair then you wont have to balance them that much. and as far as the rest of the assembly...I think its been covered once or thrice.

GodSquadMandrake

I don't know but I would be interested to find out because it is hurting my brain. Rotaries are supposed to be simple but I just can't figure out how this would work.

fcdrifter13

Well thats the part that got me. THey do match up. They are S4 rotors and Ill have to go look at the number but they are way out. They dont have anychips or anything like that to make them that way but they are way out. I have it all written down at the shop. I Am thinking that may have come that way from the factory but I am sure they would be as bad as they were.

fcdrifter13

WEll i have been looking for a link to some more info but cant find anything. But I am also thinking about were would be the best place to remove wieght from the rotor. But then that also got me thinking about the wieght of all the seals and springs. I wonder if that would affect the balance at all. Maybe I should fully assemble the rotors with all seals and springs ect and then try to balance them.

Any information on this subject would be greatly apprectiated.

fcdrifter13

Well I think that I am thinking to much now on this subject. Now If a spinning rotor has three different sides and are on opposing side of the e-shaft then this would make 3 different wieghts at different points in time. So then that would make a total of six different wieght points. Now for the engine to be in total balance by this therory then each one of the sides of the front rotor would have to be the exact wieght of the opposite side of the rear rotor. Thus making the rotors in complete balance with each other in there rotations. But there is a problem with this theory I do not know of a way to balance the different sides of a rotor individually.

So far is any of this making any sense other than to myself. Its kinda like that orbiting theory. Were an objects center is always in balance. But the objects from its center even though connected are not in balance with each other it will cause a disturbance. This is were my theory on this is dirived from. I think it makes sense. So here is bacically what I would have to do to make a perfectly in balance rotor.

Find a way to measure the wieght of the rotor in thrids much like cutting it into 3 pieces and measuring them. But without accually cutting them. Compare the wieght of the 3rds with the other rotor and find the lowest wieght withing the 6 3rds of the 3 rotors. Then remove enough from all the other pieces to were each one of the pieces is the exact wieht. This would also include apex seals springs and ect.. AS for the flywheel were most of the imbalance is occured it would be balanced much like a tire. Rotating it at higher speed to see were there is more or less wieght and have it machined to be in perfect balance. Thus eleminating alot of vibration in the rotating assembly reducing wear in the engine. And possibly making more power.

But for the Counter wieghts I am not sure about them at this point, the way I have explained it you might be able to run without the counterwieght thus creating less rotating mass and more gains on the top end.

Well I am Sorry if none of this made sense. I am just wanting to try all of these Ideas in my head all of a sudden. Feel free to post your comments thoughts flames.

Alex Saunders

fcdrifter13

Hmm Ddub did just bring up a good point about the counter wieghts that I had over looked. the rear is used to position the flywheel. Now the best way to have the engine in balance in the way I depicted would be to have the rear counter wieght were it needs to be. But on the opposite end of the e-shaft have a counterwieght of the exact same wieght. Ok lets say that the rear conterwieght is sitting on top of the e-shaft(remember this is just to get a point across) then I would have to make a counterwieght of the exact same wieght that would sit on the bottom of the e-shaft on the front. This would act like cancelling wavelengths. Thus the rear counterwieght could position the flywheel but would not be part of the eqation for the balance of the rotating assembly.

Any comment or questions, gripes, bitches, or anything like that.

Alex Saunders

TonyD89

iTrader: (10)

I'm rebuilding a motor and also work in a machine shop. I want to lighten my rotors by machining like RB and other people do. I have asked about balancing (RB) and they said they use a "Propriatary Formula" to calculate the wheight of the rotor "Including oil wheight". They would not tell me how to calculate my balnce wheight in proportion to my counter-wheight. I would be very interested in any information that could help me in this matter.

fcdrifter13

The only reason I started this is because we tried it in the shop and couldnt figure it out. Then I was sitting here looking at **** and this just kinda popped into my head. So I thought I might as well right it down before I forget it.

TonyD89

iTrader: (10)

FC, this is good head candy. I believe there might advantages to balancing. Even a basically stock motor. When I took my '89NA apart, I was surprised how differant the rotors looked. One was smooth and the other had grooves like it didn't go through a finishing operation. I know the previous owner and am sure it is the stock motor.

fcdrifter13

Ok correct me if I am wrong here somebody. But you were talking aboutthe oil in side the rotors right. Well I am pretty sure a liquid spinning balances its self out by pressing up against the side of the rotor. But hey I am not even sure if there is oil in the center of the rotor or not while it is running.

If there is it would be like taking and swirling water in a pitcher if you spin the water fat enought it moves to the oputside and is in balance. because the force is being distributed evenly. But hey I never did take physics in school. I took bilogy instead. So all of the stuff I know is basically from my head and a couple of physics books I have read.

TonyD89

iTrader: (10)

Oil sloshes around in the rotor. It is not always constant. That is where the secret is.

TonyD89

iTrader: (10)

Point, flat, point, flat; the rotor is not shaped like a pitcher. Think!

fcdrifter13

Yeah but the inside of it would basicaly be the same. Oh damn I just thought about something. And you are right. It would be very unbalanced because the oil would go into one oiont and then not beable to flow evenly between the other because of cintrifigul force. Ya not spelled right I know. I have benn looking at this more and more but I need more info on the workings of the internals of a rotor.

TonyD89

iTrader: (10)

I told you what I know. If you can get more information on what percentage of the rotor wheight, including oil, that balancers use please tell me!
If anyone else can help me get this info, speak up.