Flywheel Balancing, Who? Where? How much? Options

[sgomes]

With an electric conversion you don't have a noisy and shakey engine to mask slight vibrations. Before I pulled the car apart for a tranny rebuild I did notice a very slight vibration with the motor spining and the clutch in. It could have been caused by something else I won't go into but my bet is on an unbalanced flywheel. It has very few miles on it so the clutch surface is fine.

So the usual questions:

Who can I send it to? (I'm in the bay area, Cali)
How much can I expect to spend?

[Brad Roberts]

Closest to us is Ellsworth machine in Mountain View off of Old Middlefield.

Wait.. another one close to you is Donsco. I *think* they do balancing in house there.



B

[sgomes]

I just read an interesting discussion over on the EVDL (Electric Vehicle Discussion List). The hotrod guys over there were talking about balancing not just the flywheel but the flywheel-pressure plate assembly. Basically they removed the clutch disk, replaced the pressure plate and spun up the motor.

The procedure was to remove one pressure plate mounting bolt and spin it up again to see if the vibration gets worse or better....etc etc.... Eventually they added washers to the appropriate bolts to balance the assembly.

My question is: Has anyone done this here? Is the the "standard" procedure? It would seem that not doing this would kinda negate any balancing of the flywheel.

[SLITS]

Ok, that might work fine - but running an engine in the chassis doesn't seem as sensitive as a balancing machine.

On our racing engines, we balanced the entire rotating assembly - damper, crank, flywheel and clutch as a unit (and yes, it was an internally balanced engine).

[bondo]

I had this done on my electric opel. I machined the flywheel myself to accept a Chevy S-10 towing clutch (which involved machining off the step and drilling a different bolt pattern). The machining took off some of the factory balancing holes, and by the time it was done you could notice it was out of balance at just a few hundred RPM. I took it to a machine shop in Roseville, CA (it was just an ordinary machine shop, that does balancing) and they balanced the flywheel by itself, then added the pressure plate and balanced again (by drilling holes in the pressure plate flange). They of course marked the PP and flywheel so it could be reassembled the same way. It cost a little over $100.

[sgomes]

Thanks Bondo. I'll give the shop Brad mentioned a call and see if they can do the pressure plate as well.

Slits: yet another benifit of getting rid of that awful engine and replacing it with a fine tuned electric motor.... (IMG:style_emoticons/default/laugh.gif)

[sgomes]

Yep, just called Ellsworth Automotive and machine (or something to that effect) and they confirmed that they highly recommend doing both at the same time. $105 for the set. It'll be there tomorrow.

[bondo]

Sounds about right! Don't forget to bring the bolts you plan to use for the pressure plate (Like I did) (IMG:style_emoticons/default/smile.gif)