Flywheel wobble ?

[Crofter]

If there were any worry about the integrity of the hub, further drilling and installing set screws to point load it sure is going to cast more doubt on it. If the bore is loose and or crooked, it actually would need six to position it accurately but provides not nearly enough bearing surface to dependably stand up to the pulses of a single cylinder engine.

What are you trying to cure? The properly fitted gib key system works with the main issue being removal if you dont have a puller. Using set screws to regulate a loose or crookedly bored hub is not very good engineering. Usually if  a set screw is used it bears on the key itself as having it dig into the shaft itself raises metal crater that makes the flywheel hard to slide and scores it up.

[Crofter]

Do a google search on "flywheel mass calculator" and you will come up with something you can just punch the numbers into. Distance from centre X pi gives the velocity increase and I believe nergy stored goes up on the square of velocity. Limiting diameter to 16" would need a huge increase in weight to get the same momentum storage.

[Crofter]

A lot of work for a machinist. Especially if two are needed.

This is a perfect excuse for a CNC machining job. The flywheel would consist out of multiple parts. A central hub turned from solid round stock, 1/2" plate steel for the intermediate area and then the outside sections which bolt onto the 1/2" plate steel. I would think that the second flywheel would cost less than 1/2 of the first because the job has been already set up.
The outside sections could be CNC'd from solid plate in 1/4 sections so that you have 4 sections on each side of the flywheel. You could vary the plate thickness based on how much rim weight you want but you could also stack additional sections for more than 8 total sections.
Hope that makes some sense.

Hey Jens, dont forget to spec. out the scatter shields for those segmented flywheels! lol!

It could be done as you describe but there is a lot of material involved to get the rings out of and lots of holes to bore true. I think you would still have to turn it to get true. Unless you can steal or find the material and blackmail a CNC machinist, I think it would be cheaper to buy a new 10-1 from John F, keep the flywheels and sell the rest for parts!

[Rom]

The gib is still installed, just 2-3 set screws to help it hold the flywheel on, spaced evenly around the hub. most of the listers I have seen have the gib head damn near flush with the hub face aswell as the set screws. Sure makes it a pain to remove the keys in some cases. I suppose the set screws help with the continual working on the gib key on the drive flywheel.

Rom

[Rom]

    Indeed, if the bore of the hub of the flywheel does not match the size of the crank, setscrews are not the way to go. I would start with boring the flywheel and bush it to the correct size, if machining for taper lock was cheap enough, I would definately do that. Yall must understand, that probably except for my Anand 16/2, ALL of the Listers down here are Dursley, and the flywheels fit the cranks. Only thing I have noticed about our RA Listers, is that many lose their drive flywheel to a loose gib, which I believe is do to that wheel being the power transmission wheel, with all of the jerking and such that comes from driving a belt on that wheel.
   The VA that I am working to salvage atm has sat in the rain with no fuel lines and a loose injector for 12+ years. The Alloy piston is solid in the bore. I have found what I believe is the failure that stopped this engine from work. The oil holes in the conrod had plugged solid with sludge. Almost an 8th inch play in the big end, and crank journal seems ok. The original 850rpm machines had tin bearings with bronze backing on steel shells, where as the 650s only had tin. This engine wore almost all of the oil grooves out of the upper shell.
   Far as I can see, loosing the drive flywheel, running til it had an oil failure like this VA, lack of cheap parts, and a new power grid is the combo that killed our listers.

Lost my train of thought... lol
Rom

[mobile_bob]

Rom:

were the original lister brg shells very thick with tin layer?
or were they more like modern shells where the babbit layer is very thin?

i would think they would have had to be quite thickly layered with babbit/tin so that the shims could be taken out
to tighten things up, if the layer was thin removing shims might tighten things up but you would be into the bronze layer
pretty quickly.

bob g

[Ronmar]

Ronmar,

Sorry, but I'm having trouble following your description.
What "two piece collars" are you referring to?
Does you solution involve a gib key or a standard straight key a shown in my sketch?
Are there any set screws in your scenario?

thanks,
veggie

Here is a drawing to help visualize it.  The collars I am refering to are available in many places such as Mcmaster Carr, and Fastenall where I got mine. They are a steel donut, split in two and fastened together with two opposing allen head setscrews which clamp the halvs onto the shaft.  The way I am talking about installing them still uses a gib key, but one made long enough to allow the collar and a large flat washer to be fit between the head of the key and the flywheel.  One half of the outer collar would need a notch milled into it to pass the key, and 3 holes drilled and tapped.  One hole in the middle would be to pass a small screw that would pass thru the head of the gib key and affix it to the collar.  Or if the key fits close enough, it could simply be tack welded to the collar.  The other two holes would be larger and be placed on either side of the key head. These would be used to apply force to the colar to pull the gib key out of it's slot.   The collar clamps to the shaft and attaching the key to the collar prevents it from backing out.  A collar on the inside prevents the hub from walking away from the key.    When it comes time to remove a flywheel, you simply remove the collar clamp screws and remove the inner collar.  Then you loosen the outer collar screws and install larger bolts into the holes adjacent the key and use them to put force against the inner washer(shown in blue) to draw the key out/push the flywheel in

You could also do it with just the two holes drilled and tapped for the puller bolts, and have them hold a lighter metal bracket that goes out around the head of the key to secure it to the collar(less machine work).  These collars are not very expensive, and I use 4 of them to make sure my flywheels/keys stay in place.  I do not have mine rigged like this, as I did not think of this idea untill after I did my gib key fitting:(

[veggie]

Ronmar,
AaaaaH! your drawing makes perfect sense.
Thanks for taking the time to do that.
This solution assumes a proper gib fit 

Everyone else...
After all the discussion and suggestions, I intend to work forward from the simplest/cheapest solution to the most complex and expensive.

Possible causes are as follows:
1] Poor fitting gib key does not have uniform interference causing the flywheel to cock to one side (as in previous sketch)
2] Hub bore is too big for the shaft
3] Hub bore is not true (parallel) to the OD of the flywheel

To start with, I will do some serious taper measurements on the hub keyway and the gib keys.
If necessary, I will have gibs machined to perfectly (within machining limits) match the taper of the keyway.
Assuming the bore is not oversized to the shaft, the custom gib keys should solve the problem.

The flywheel is coming off tonight, so I should be able to get to the bottom of this fairly quickly.

thanks,
veggie

[luv2weld]

For those of you thinking about getting the 2" split collars-----
Here is a link to get them a lot cheaper than McMaster Carr or Fastenal.
https://www.surpluscenter.com/item.asp?catname=&qty=1&item=1-2768-200

I have been dealing with this company for years.

I use them to lock my flywheels on also.

Ralph

[veggie]

I had a new key machined to match the taper of the bore.

ronmar, that was an excellent suggestion to use candle soot as a marker. It worked really well.!
Mark the gib with soot ...tap into place...observe the high spots....file as necessary.....repeat....repeat....repeat

The flywheel now has a wobble of approx. 1/64". I think that's about the best I can get with this flywheel.

Man....I really dislike the gib key arrangement. Every time I whack on the key to drive it into place, I think of the effect it's having on the tapered roller bearings.      Not good.

cheers,
veggie

[Henry W]

Hi Veggie,

I understand what you are saying about hammering the gib keys home. If you an find about 500lbs of steel and locate it against the other end of the crank while hammering the keys home it should help dampen the blows on the bearings. And if you can put the weight against a solid wall it would help even more.

Henry

[Crumpite]

Hi Veggie,

I understand what you are saying about hammering the gib keys home. If you an find about 500lbs of steel and locate it against the other end of the crank while hammering the keys home it should help dampen the blows on the bearings. And if you can put the weight against a solid wall it would help even more.

Henry

You've already got the inertia of a couple of *very* heavy flywheels to help absorb the shock.
And after all, they've been using this system for how long with no major problems (that I know of.)

Crumpite

[Geno]

I tap in 2 opposing wooden wedges between the flywheel hub and the bearing housing to minimize pounding on the bearings. Quick and easy, just in case.

Thanks, Geno

[rcavictim]

The flywheel now has a wobble of approx. 1/64". I think that's about the best I can get with this flywheel.

cheers,
veggie

Congrats! Sounds like you made a huge improvement over 1/8" that you started with.  Perhaps for the final 1/64th of an inch you can use WobblygoopTM.  Lemme know if you can find some. Last time I looked it didn't exist.