I’m planning to balance my rotary engine locally using a CWT Multi-Bal 5000, and I wanted to share my research + get some opinions from people who actually understand rotaries.

The shop I’m going to doesn’t have experience with rotary engines, so I had to dig deep and figure things out myself.

I’m working on a Mazda 13B-REW and going with the “Method B (No-Cut)” approach — meaning I won’t be matching rotor weights, but instead using different bobweights to simulate each rotor.

Here’s what I’ve got so far:

• Front rotor: 4304g
• Rear rotor: 4320g
• Constant mass (seals, springs, oil): 592g per rotor

So:
• Front bobweight = 4304 + 592 = 4896g
• Rear bobweight = 4320 + 592 = 4912g

And I’ll run the machine at 0% reciprocating mass since it’s a rotary.

Now I’ve got 3 main questions:

1. Is the 592g constant mass actually correct for a 13B-REW? I’ve seen mixed info and want to be sure before committing.

2. Has anyone here done rotary balancing on a CWT machine using this method? Especially with different bobweights — did it give accurate results?

3. Is there any way to actually buy a proper rotary bobweight setup? Or is everyone just building custom ones for their own rotors?

From what I understand, most shops use custom-made bobweights to simulate the rotor + seals + oil mass, so I’m not sure if there’s an off-the-shelf solution or not.

Also open to any advice before I go ahead with this — I’d rather double-check now than regret it later.

Appreciate any input from people with real rotary balancing experience 🙏