Flywheel wobble ?

[veggie]

Gentlemen,

I noticed a wobble in the flywheel when I slowed the engine down to 450 rpm.
The shaft seems to be dead true and the belt does not track side-to-side but the edges of the flywheel seem to wander left-right. Might just be the machining
Total movement is about 1/8 inch side-to-side

thanks,
veggie

[Henry W]

Hello Veggie,

That does not look that bad.

Did you check the gib keys to make sure they fit properly and are tight before you started the engine the first time? If the gib keys fit as required and are tight I say you are ok. I remember I had to grind one gib key to seat properly.
It was seating about a 1/3 on the thick end of the taper. The best way to check is to remove the Gib key and dye the top taper of the key and slam it back in and remove it again and look to see how much dye was removed. If the key has to be reworked do it on the side that seats on the crank shaft.

Henry

[Ronmar]

That dosn't look too bad.  One quick check you can do is to bring a piece of chalk up against the outside of the wheel when running to see where the excursion is in relation to the gib key.  As Henry mentioned, if the gib key is only engaging at the edge of the hub, this could cause the flywheel to wobble a little bit.  Ideally, the gib key taper should match the taper cut in the flywheel so the top gib key face contacts along it's whole length.  If it dosn't, the little bit of play that allows you to slide the flywheel on and off of the shaft can be taken up unevenly and tilt the wheel.  This would be the case if a flywheel was installed backwards and the key driven home It would only contact at the outside edge and would alter the wheel in it's plane.  Incomplete key engagement could also mean that the wheel could shake loose more easilly.

As a little added insurance, I purchased four 2" locking collars.  I put one on the shaft, installed the flywheel against this collar and then installed the key.  Once the key was seated, I installed a second collar outside the key head on the shaft.  In order to come loose, the colars will have to move before the key/flywheel realtionship can be altered.  The collars are about 3/4" wide, and about that thick.  It also kind of guards the key head and makes it look a little less hazardous as the collar is mostly smooth when installed. 

I noticed something spinning between hub and engine case on your video, what is that?

[WGB]

Fitting a key = Persian blue, fit, file file file, Persian blue, fit,  file file file, Persian blue, fit, file file file! LoL fun fun fun!
Actually I kind of like fitting a key. 

[veggie]

I noticed something spinning between hub and engine case on your video, what is that?

There is a 5" sheave that came on the engine when new. It's used to drive the water pump.
You may have also noticed the v-belt hanging there.?
I did not use the stock water pump so the belt and sheave are unused.
The belt cannot be removed without taking off the flywheel.
I think I'll just cut the belt off in the near future. I was waiting in case I came up with an idea to drive something with it.

veggie

[mobile_bob]

gotta love a "trapped" belt design!

we run into that from time to time on heavy trucks, where you have to remove the fan/fandrive/clutch assembly just to
get a belt out that is too short to slip past the fan blades.

or worse, have to remove all that, the A/C compressor and a plethora of other stuff to replace a waterpump belt
on a N14 cummins, thats always fun.

10 dollar belt and 300 bucks in labor?

gotta love those engineers!

bob g

[veggie]

That's where those "linked" v-belts come in handy.
Make them up to any size needed and no removal of accessories.

I can leave that belt where it is. It's not in the way.
I would have loved to drive an automotive alternator with it but the ratio is all wrong.
I need a much bigger sheave in that area to make it work.

Instead, I will be driving the automotive alternator from the OD of the flywheel.
23" flywheel to a 2.3" alternator pulley.... a 10:1 ratio.
So....when I run the engine at 420 rpm for battery charging, the alternator spins at 4200 and puts out 86 amps.

Back to the stock crankshaft pulley... How about driving a small gear pump for oil circulation and filtration?
A good project for next winter. Keeps the oil nice an clean (filter out all the babit and metal particles  ).

veggie

[veggie]

*** UPDATE ****

Well, I finally found time to remove the flywheel in question and do some inspecting.
The gib key was a mess. Not a smooth taper, but a lumpy bar of metal.
I cleaned up the key way's and installed a new gib key.
The new key went in as "smooth as butter" and gradually came to a halt before butting up to the flywheel hub.
As a precaution, I installed some locking rings on the shaft.

While I had things apart, I decided to move my belt drive inside the flywheel and out of the way.
I sized the drive with a 4.5:1 safety factor (27HP) so I'm not expecting to change the belt for a while.

I fired her up, and the flywheel wobble is gone. I turned out to be a bad fitting gib key that was making contact at one end of the bore only.

thanks everyone for your suggestions...
veggie

[rcavictim]

So basically you are telling us all that you 'got lucky.     Nice when things work out like that!

[veggie]

Unfortunately the saga continues.  
When I ran the engine today, I noticed a bit more vibration than normal.
The rig slowly walked (rotated) on the floor until I had to shut it down before it pulled on the rad hoses.

I have addressed the the gib key issue and now it looks as if there are two possible remaining issues.

1] the flywheel is cast with a wobble. Not machined properly

2] the fit of the shaft and the flywheel bore is too loose and causes the flywheel to tilt when the gib is driven in.

I mounted a marker pen and moved it into the flywheel after turning off the engine and letting it spin down with no compression.
The rig was dead smooth, but the pen contacted the flywheel on the EXACT opposite side to the keyway.

To eliminate case #2, can anyone tell me the proper OD of the shaft and the ID of a flywheel?
I measured the crankshaft to be 1.997" on either side of the flywheel.

I have attached two pictures to illustrate this potential condition.

Thanks in advance,
veggie

**** UPDATE ****
I also set up the marker pen on the opposite side (inside face) of the flywheel.
The marks now appear on the SAME side as the keyway confirming that the flywheel is oriented as shown in my sketch.

[Crofter]

The bore may not be true with the rim or the gib key may not have the same taper as the keyway and is not enforcing the clearance evenly end to end of the bore. There is an excellent post on proper fitting of a gib keys ( may be on LE Forum)  How much lateral runout do you actually have. Do you have it on both fly wheels? Is the crank itself free of runout?

If the bore is not true with the rim, you may have to live with it by balancing it out. First you have to find out what is the exact cause of the rim wobble. I felt that the drilled factory balancing holes used no regard for dynamic balance and was not even correct for static balance.

I did not mic. the id of the flywheels bores but they are a free sliding fit on the crank so likely more than .002" The gib key should force all the clearance evenly toward the key way side of the fitup. How much runout on the rim faces?

[veggie]

Crofter,

The runout is 1/8" on the faces.
Enough to put a lateral shake into the rig when running at 650 rpm.
If I slow down to 425 everything smooths out.

I also set up the marker pen on the opposite side (inside face) of the flywheel.
The marks now appear on the SAME side as the keyway confirming that the flywheel is oriented as shown in my sketch.

veggie

[Crofter]

Wow! that is a lot of wobble. Is the shaft itself true? How about the other side? Though it could be done, I would not like to externally balance that much runout or to run a belt on it without creating issues there too.

In that case I would look into boreing the hub to take an SK, I believe taper lock hub mounting system. I think some flywheels come pre done this way.

[lowspeedlife]

In that case I would look into boreing the hub to take an SK, I believe taper lock hub mounting system. I think some flywheels come pre done this way.

This is the fix I would employ. The only flywheels I've seen that come bored for a taperlock SK/Browning style bushings are the custom wheels from Stationary Engine Parts.
   Scott R.

[veggie]

Yep, I suppose it's possible to bore the hub for a taper lock bushing.
I am a big fan of taper bushings.
Might be a bit expensive. A 23" (180 lb.) flywheel would require a big lathe.

Anyone else done this?

veggie