RONIN FC

Wow, this has been coming up alot lately? Its hard to find straight answers.

Speedworks

Can an excentric shaft and/or complete assembly be balanced like an ordinary piston engine or do you need special tools?

Nospig

Up to rx8 mazda balanced rotors static , now they are injected with a gel and balanced dynamically.

Every engine i have worked on that has been balanced by a so called expert has had a nasty vibration at some rev range . One rotating asssembly was taken back 3 times each time hed say now its perfect. B S. When it died an apex seal broke ( shattered ) suprise suprise oppisite to that seal a bunch of balancing marks hed made.

Engines with the original rotating assembly or untampered with matching parts work best.

But from a shops point of view , an unbalanced engine isnt going to last as long , and they can charge you for it. Vibrations = broken apex seals , chatter marks and bearing failure.

Speedworks

Thanks, but I'm putting together my own engine. I'll be reusing all parts except for the front iron. New housings as wel.

new eshaft and rotor bearings as well.

I'm in Europe and rotary builders are rare to non excisting. I need to know if the engine can be balanced like a normal piston engine...

RONIN FC

Ive tried making that point many times. People just insist that having a shop balance their assembly is better, but yet no one can tell me how they can account for different oil volumes and casting differences inside the rotor. Even different kinds of oil can have a different weight.



Now, if youve had rotor lightening and such, I can see a balance job bieng needed.

Speedworks

Thanks Ronin. My car is a turbo so in that perspective not making over 9000 rpm regularly like NA's. I'm just trying to make sure I do the best job I can do instead of having to deal with something as stupid as that afterwards and need to hear 'I told you so'.



I guess the fact that I'm reusing 98% of the original parts will contribute to that.I hahve little wear on the bearins now and will be masuring the e shaft in a few days..

Nospig

IF all the parts are correct for your engine , the factory balancing is fine. With the rotors they are stamped with A B C or D you can use an A with a B or B with a C etc but do not use A with C or B with a D etc and they will work just fine.

GMON

Ive had one done. Dont worry about the effin oil. The rotor spins. Oil seeks a level on inside the rotor and is replenished at a constant rate relative to each rotor.



But yeah, anyone that can do a piston engine can do a rotary (as long as they have half a brain). ~$150 USD depending on how far off your stuff is.



Rotors end up being the same weight and spin balanced individually. Eshaft checked individually then front and rear counterweights are added with nuts and washers then that assy is done. Clutch and pp are also added to the mix.