i can do motorbike wheels with a bar in my vice and it works fine.but i would like to balance my flywheel as i got it from ebay and its been skimed down to 6 kg.and i dont know it its been balanced or not.
or can i do it on a car wheel balicing machine at kwik-fit as i have a mate who works there.i was just going to drill it a bit and not add weights. ??????

YOU DONT.

Unless you have already lost your legs and it does not matter if it parts company at 6K revs and comes crashing through the bellhousing and tunnel panneling

I would pay and have the thing done right.

Its worth researching how toolrooms balance grinding wheels. basically a shaft through the disc, then have the shaft on 2 level blades so you can find the heavy spots. After balancing you should be able to rotate it to any position and it wont move.

Method you use to balance could have effect on durability. Metal removal or add weights.

Is it cast iron, if so I would be very wary about using it, see comments & pictures in this previous posting

http://www.locostbuilders.co.uk/viewthread.php?tid=79595

[Edited on 8/1/09 by wicket]

your link has an extra v at the beginning wicket

Static ballance is very different from dynamic ballance.

I'm a locost champion but not in this instance.

Best to have this done professionally for safety reasons. Also it may not have a neutral balance and require a specific weight somewhere.

For example my engine only came in automatic cars and I have a manual behind it. The A/T flexplate has a heavy weight on it to offset the extra weight of the supercharged bottom end. I need to have the M/T flywheel balanced so that it is in the same spot, and same weight (no M/T cars came with a supercharger so no balance weight)

Cheers.
Cory

Hi

It is not just a case of balancing the flywheel on it's own. You should be balancing the crank flywheel and clutch cover as a complete unit to do the job properly.

It is money well spent though if the flywheel has been lightened significantly.

Cheers Matt

I am running a cast lightened flywheel on my pinto which has basically had both of the large rings of casting removed which takes is down to about 6kg. This was then carefully balanced on a grinding wheel balancer which has worked very well. Its regularly revved to 7500-8000rpm and has been fine.

Due to the positioning of these rings (i.e at the circumference of the flywheel where the weight makes the most difference) removing them is going to make little difference to the strength of the flywheel in my opinion - it's not like you are removing strengthening ribs. (There is less weight at the periphery of the flywheel therefore less force on the central sections holding it together). Where the problems come is the increased inertial forces as the engine is now able to rev faster with no load.

This is, of course, only my opinion and experience. You take your own risks using a lighted/cast flywheel!

If the flywheel has been lightened but not balanced are you 100% sure that it has been done professionally? If not, personally I wouldn't use it no matter how much of a bargain or how expensive it was.
Transverse engined Autograss cars have to have a flywheel guard (steel plate) fitted and I've seen the mess a flywheel can make of even a substantial steel guard never mind 1mm ally covering a tunnel!