Balacing a Chipper Shredder Flywheel

[Michael_P]

I have two chipper shredders I got for free a while ago. One is an MTD 5HP and the other is a Craftsman 9HP. The bodies are identical and all parts interchange. I am looking to combine the best parts and build up a decent chipper shredder. Both engines work well after carb rebuilds and general cleaning. The issue I have is both of these chipper shredders sat outside for a while causing water to pool inside causing the flywheel to rust, creating severe balance issues and vibration. The flywheel weighs probably 25 pounds or so with no blades on it. One is severely rusted which will end up at the scrap yard. The other flywheel looks to have minor rust on one side and could be easily balanced. The question I have is; What kind of balancing device would I use to balance such a heavy flywheel? Also; What is the preferred method to add or subtract weight to this flywheel. I have seen where people have drilled heavy spots only to have debris get inside of the holes and clog things up or knock it off of balance.
I couldn't find anything on Google or YouTube.

 

[Brybo86]

Rough up a spot then add some JB weld?

 

[mjoekingz28]

Can a front-end shop turn them as they would rotors?


And then check run-out. Is there a machine that checks balance like a tire balancer, but on metal parts- or do you just measure the thickness at various points?

 

[rubberchicken]

Originally Posted By: mjoekingz28
Can a front-end shop turn them as they would rotors?


And then check run-out. Is there a machine that checks balance like a tire balancer, but on metal parts- or do you just measure the thickness at various points?


brake rotors spin much slower than engine flywheels, and they rarely attempt to balance them outside of the factory. I think you would need to take it to a engine machine shop that can balance flywheels, but compare the cost vs. a new flywheel.

 

[Pop_Rivit]

Originally Posted By: Michael_P
What kind of balancing device would I use to balance such a heavy flywheel? Also; What is the preferred method to add or subtract weight to this flywheel. I have seen where people have drilled heavy spots only to have debris get inside of the holes and clog things up or knock it off of balance.


A machine shop.

Originally Posted By: mjoekingz28
Can a front-end shop turn them as they would rotors?


No.

 

[Trav]

Make something like this from a bicycle wheel axle (no grease on the bearings just a little WD40) and a couple of pieces of angle iron to find the heavy spot, make sure it is clean and rust free before doing this.
It will spin free enough that the heavy spot always goes to the bottom, mark it in the center of the heavy spot. You have a few options to balance it, either add or subtract weight. Either add a stick on wheel weight to the light spot or remove weight from the heavy end by drilling, dimpling or grinding. Grinding on the rear face may be the easier option if its only an ounce or so.

Start in the center of the heavy spot and work out about an inch to either side of the center, take only a little at a time and check it. Repeat until it stops randomly. It should get it close enough so it doesn't vibrate like crazy.

http://www.discountramps.com/motorcycle-...CFYSKswodXecCTw

 

[BrocLuno]

The other thing you need to think about is the crank interally balanced, or does it depend on the flywheel? Many OPE engines are not balanced at all. No throw weights on the crank, so they will shake because of engine design. Has nothing to do with the big flywheel.

But I'd do the above and get it close and see what happens... Do you have a welder?

 

[Michael_P]

I do have a welder (Actually I have MIG, TIG, Oxy/Acy, Arc and Heliarc welders). I should have probably said, the Craftsman body was destroyed due to excessive vibration. It was so bad, that you would have to chase it in the yard it would move so much. Much of the sheet metal ripped like paper after a few hours of use. I also have a lathe and I'm thinking about building some sort of dummy shaft mounted on a piece of steel to get a feel for balance. I could just go out and get a new chipper shredder, but this has turned into a cool winter project. If I'm not satisfied with my dummy shaft balancer, I'll find a machine shop or mower shop to balance.

 

[Cadmanjwm]

I would mount a dial indicator on the engine first to check for a bent shaft as a probable cause of vibration. To check the blade rotor for balance one should remove cutter blades and using a supported shaft do a simple gravity spin to find and mark the heavy spot. Add a small set screw opposite the heavy mark with masking tape. If things balance then one has a good idea of the hole size and depth to drill at the heavy end.

 

[Michael_P]

I dial indicator is a very good idea. Its obvious rust has eaten away a bunch of metal on one side of the flywheel, but with all that vibration the crankshaft could have gotten bent. I'll check it out after dinner tonight.

 

[ironman_gq]

Single cylinder engines aren't balanced too well to begin with, the flywheel on the engine is usually balanced close to what the piston and rod weigh but not a whole lot of thought goes into it. I wouldn't worry about the engine, just have to get the chipper wheel to spin true, You could drill out the heavy spots and fill the holes with epoxy or JB weld so it spins true. An engine machine shop could probably balance it on a flywheel machine, just make sure that all balancing is done with blades or blade blanks installed.