Running a 20/2 with only one flywheel

[Jens]

I need to figure out where a particular pinging noise comes from. It seems to be coming from the gib key. The only way of confirming this would be to run with only one flywheel. Is there any reason why I shouldn't do this?

I really can't see the key to have clearance anywhere but the gib key seems the most logical place for the noise to come from. The noise is more pronounced on heavy load. I am pretty certain there is no side clearance issue between the gib key and the crankshaft and the key is seated very firmly. The only possibility appears to be side clearance between gib key and  the flywheel gib slot sides. Of course the other possibility is clearance in the connecting rod journals on the crank but I refuse to believe that ... I would not be a happy camper .....

Jens

[AdeV]

The only way of confirming this would be to run with only one flywheel. Is there any reason why I shouldn't do this?

The only reason I can think of is the massive imbalance of your engine which will almost certainly damage your crankshaft, and may even cause the engine to break loose & smash itself, the surroundings, and any people or animals within, into many tiny pieces.

Please, just don't do it.

Can you upload a video to YouTube which demonstrates the noise?

[billswan]

jens

Try it it may work. Start it with no load at Idle and accelerate up slowly it won't take long and it will become apparent if one less flywheel will unbalance the engine so that it shakes too badly. Not sure if you could hurt the crank though so you are on your own there. I would think for an unloaded test you would be Okay. Not at all sure if I would put it under full load it is apt to sound, and run oddly though. I remember MANY years ago I had a 2 cylinder John deere tractor that was destin for the scrap yard but it still run......So i had always wondered what one would sound like without a flywheel. Well I loosened up the clamp bolts that held the flywheel on the splined crank started it up and proceeded to use a bar to tap on the smooth edge of the running wheel eventually it popped off the end of the crank dropped to the ground spun in place for a second and promptly took off across the farm yard to my surprise. I thought it would flop on its side and spin to a stop. Well we won't talk about what it hit..... now back to the running 2clyinder. Well the engine run but without it's only flywheel you absolutely would not recognize the sound,it had to be kept running at an advanced rpm state or it would stop. How do I know well it stopped immediately after the wheel came off and you guessed it I put the flywheel back on and tried it a second time. This time when I knocked the wheel off I had a steel loader bucket in its path so as not to hit any thing of value. Oh and a long twine string hooked to the throttle so I could add more fuel from a safe distance. Of course I was about 18 years old at the time so give me a break guys I lived through the experience but the engine did not. The fan blew apart, yes I was expecting that and I was well off to the side when it came apart. It was along time ago can't remember much else about the experience.

Billswan

On second thought maybe ADEV is right you could break your engine!!

[JohnF]

Jens;

I wouldn't recommend it - too many things could go wrong and might cause soft tissue damage.

About the pinging noise - run the engine so you can hear the noise then shut off the fuel, as the engine is coating down does the noise disappear?  If so it is a loose gib key. 

[XYZER]

I have had a loose gib key and it sounded like a knock not even close to a ping.....but it sure could be.

[quinnf]

Yes, what John says.  If the key/flywheel clearance is excessive, the crankshaft will accelerate out from under the flywheel until it fetches up against the gib key.  You can tell if this is happening by running up to speed, then lifting the stop lever.  If the key is REALLY loose you may still hear the clanking on compression strokes.  But if, when you lift the decompressor, the noise goes away, you found your problem.

You might end up having to fit a brass shim between the side of the key and the keyway in the crankshaft, and/or the keyway in the flywheel.  I had to do both with my Ashwamegh 6/1.  Brass shim stock worked great.  After I shimmed the keys in the flywheels the noise went away. 

Quinn

[AdeV]

Well I loosened up the clamp bolts that held the flywheel on the splined crank started it up and proceeded to use a bar to tap on the smooth edge of the running wheel eventually it popped off the end of the crank dropped to the ground spun in place for a second and promptly took off across the farm yard to my surprise. I thought it would flop on its side and spin to a stop. Well we won't talk about what it hit.....

I know I shouldn't, but ROFL! Excellent turn of phrase...

Jens - I'd forgotten you had an internally balanced engine; but, whilst that does suggest you'll avoid any serious shaking issues, Bill's thought that it might all sound too different simply due to the lack of flywheel seems logical to me, even if I couldn't prove it. I should think the engine will stay running OK, so long as you don't load it; the huge mass of the flywheels is partly just to try to smooth things out as much as possible, beyond the simple "keep it turning between power strokes" function that a light flywheel provides.

I think JohnF's got the answer for you; but I'm not sure that'd eliminate "diesel knock" as a possible cause of the sound? Is it a metallic pinging, or more of a dull clacking noise?

[quinnf]

Conceivably, without enough flywheel inertia to carry it through the first power stroke, the engine could also kick back.  If it does that, and your hand is on the crank handle . . .

Quinn

[mobile_bob]

Jens:

i don't see why that would not work?

there is a method known as the "brittle laquer" method used to determine stresses
wherein you coat a test piece in laquer such as a conrod and then run it
after which you look it over for fine cracks which indicate there is flexure in the design
which of course leads to failure sooner than later.

nail polish used to be laquer based i think, surely if it dries hard it will crack if the flywheel
is moveing seperate from the crankshaft.

why not give it a try!

bob g

[veggie]

How about the old stethoscope method!
Touch it in various places and try to pinpoint the source.
Just be careful poking around the running engine.
(Please take off your neck tie before attempting this   )


Good luck,
Veggie

[AdeV]

How about the old stethoscope method!
Touch it in various places and try to pinpoint the source.
Just be careful poking around the running engine.
(Please take off your neck tie before attempting this   )

If you've ever watched Das Boot (the mini-series version ideally, but the "director's cut" film at least), you'll see Johann the engineer do exactly this while U-A's diesels are in full song. Mind you, he also has some cool taps on the side of each cylinder which allow him to shoot blue diesel flames half way across the engine room

If you haven't watched Das Boot, I strongly recommend it. Probably the best WW2 film ever made, by anyone, ever.

[Apogee]

Jens,

I don't think it will be an issue running it missing one flywheel.

I own both a Lister CD (single) and a CE (twin).  While mine are in parts and not assembled yet, I've done a fair amount of research on each...

Both were offered in a marine version and both only had a single flywheel in that config.  Granted the flywheels looked heavier, but for testing purposes I'm not sure it would matter.

Take a look at the original lister marine versions of your engine if you can find info on them.  I realize that you're likely to be looking at either a 12/2 or 16/2, but I think you will likely find that they were setup with single flywheels.

Good luck,

Steve

[vdubnut62]

Jens, I think nail polish is too flexible to do what you are trying to do with it. There is a product made just for the purpose of finding movement in parts, but due to old age I just can't remember what it is!
I have had experience with loose flywheels, and they KNOCK!  Sort of a knock and rattle combined, I haven't heard a ping. And it's usually on the opposite side of the one with the problem.
Just a thought, check the backlash in the cam gears. A "loose" idler can rattle around and sorta kinda ping or ring between combustion events.
Ron.

[oiler]

DO NOT put your stethoscope against a running flywheel.........

[vdubnut62]

 You didn't say that you had a 1/16 play in the gib key? I just had to misunderstand!       I'll bet that you could try for many many years and never hit that perfect resonance of the expansion chamber again.........
Ron