Gibkey keyway offcenter in crankshaft, now what?

[hotater]

  There is a very good reason the gib keys are driven in with a sledge with a severe interferance fit in India.....the damage done in installation of the key is no where NEAR the damage that can be done should the wheel leave the machine.   

I'll echo my old Grandad when I say--- "If you don't have time to do it RIGHT now, when will you have time to do it OVER?

Straighten the keyways and make keys to fit.  That's the *right* way to do it.  In my *opinion* anything less is dangerous and should not be done.

<is my ass covered, now??> 

[clytle374]

At the moment, the whole engine can run off into the mountains as far as I care.

At this point I'm not going to trust it until I have completely tore it apart and put it back together,   I had planed on it next spring/summer but needed it to be running during the cold winter power outage season.   I don't have time now, and I agree about doing it right.

Anyway, How to run this ST head off of a 540rpm rear PTO or the 2000rpm mid PTO under the tractor,  or mate it to a 3.0L Mercedes diesel engine.  But ain't got time for that either.


 

[hotater]

  It's easy to run the ST off a PTO.  Just set it up solid to a  mount with a jackshaft on one end with the correct ration pulleys.  Drive the jackshaft with the PTO.  That way vibration is isolated and you can disconnect the tractor anytime you want without disturbing the set-up.

[clytle374]

OK, I have vented and calmed down.   Time for cool logical thought.

Mic the old keys, they are .003-.004" bigger, duh why didn't I check that first.

Could they have beat them in that hard?  Or are these keys undersized?

What metal are keys made out of?  Finding keystock here that big will be a problem.

 

[hotater]

I'm guessing the keys are 5/8" or 9/16" or ??    McMaster Carr has them in standard American sizes but Listeroids take an odd ball.  All have to be thinned dramatically.

Regular old 1018 cold rolled steel is keystock.  Any chain hardware store will have it in squares.

I have spare 3/4 gib-head keys, but my milling machine is taken apart for moving or I'd cut you a custom set.  Sorry about that.

Still laughing about the Anal-I naming.........Doug has a lot of experience 'looking too closely'.  It causes a lot of work.   

If you want to know the easiest way to do a job, give it to a lazy man to figure out. 

[clytle374]

One of the first things I learned as a machinist is, if you don't start with a square block, you don't have anything to go off of.  Nothing is square and I'm confused.

So I can't figure out why the key rocks more one way than the other.  The new keys are narrower than the old ones, and the side dimension is bigger on the little end.

I squared the bottom of the key way up quite a bit using a fine stone, I know it is slow but safer and easier to not cut the side of the keyway. 

If the noise I heard before was the keys knocking the keys shouldn't have been that tight. right??

I have collars to hold pressure on the keys(keys can't walk out, wheels can't get off)  and I check it frequently to see if I am getting motion between the shaft and the wheel(key should come loose if motion, correct?).  Is there a danger of fracturing the wheel hub? (my real fear, one running away will not cause injury) There is less than .001" side play between the wheel and key. 

Not trying to be careless here, just trying to think through my options.

Still laughing about the Anal-I naming.....

So what do I christen it with??

[hotater]

The key transfers all of the engine's mechanical energy to the flywheels by those two keys.  When you consider the forces of acceleration and loads involved it's better to do the 'old fashioned way'.  Any engine will sooner or later tear itself apart if heavy parts are allowed room to knock the hell out of each other.  Once the *slightest bit* of 'slack' is introduced into the linkages that slack soon becomes bigger and bigger until it runs out of room or strength and expensive smoke and noise results.

It's like climbing a hill on a bicycle missing a few spocket teeth to your engine....and brittle cast iron fly wheels.

Here's a few questions--

With the key removed and the wheel placed squarely above the shaft keyway, are the sides the same width?  What is that width?

Are they parrallel?

Is the top and the bottom of the two keyways parrallel?

What is the measurement, top to bottom?

If you SWITCH flywheels are those measurements and geometry the same?

[clytle374]

The key transfers all of the engine's mechanical energy to the flywheels by those two keys.  When you consider the forces of acceleration and loads involved it's better to do the 'old fashioned way'.  Any engine will sooner or later tear itself apart if heavy parts are allowed room to knock the hell out of each other.  Once the *slightest bit* of 'slack' is introduced into the linkages that slack soon becomes bigger and bigger until it runs out of room or strength and expensive smoke and noise results.

It's like climbing a hill on a bicycle missing a few spocket teeth to your engine....and brittle cast iron fly wheels.

I understand the slack will increase rapidly.  My question was.  If monitored closely will it be detectable before damaging the flywheel?


Here's a few questions--

With the key removed and the wheel placed squarely above the shaft keyway, are the sides the same width?  What is that width?

NO, keyway width is several bigger on the shaft ~.003"

Are they parrallel?

I haven't developed a accurate test for that yet, gut feeling is NO

Is the top and the bottom of the two keyways parrallel?

Very close on one, the other was .005" and after stoning the bottom out should be around .002"
But after the number of on and off cycles I did yesterday, I can't lift the 200# wheel back up.

What is the measurement, top to bottom?

Will find out.

If you SWITCH flywheels are those measurements and geometry the same?

That requires carrying the wheels over the genhead,  I'll try later.  If I don't have a hernia already.

Again, if the key was knocking it should have came out easily?

[Quinnf]

This might be helpful.

http://listerengine.com/smf/index.php?topic=962.msg12839#msg12839

Relevance is in the 5th paragraph. 

Quinn

[clytle374]

Thanks.
I will use some shim stock.  I will run the engine for longer and longer periods of time, rechecking the keys and seeing if they are working loose or will tap in further. 

If the shaft to the flywheel is moving, it should wear the key and cause it to seat deeper.

One question, he stated a few thou is OK, seems a bit much too me.



 

[jimdunne]

"So you see that the shims don't have to be a perfect fit.  As I tapped the key into the hub, at some point the key will draw the shim with it, and then as it tightens, the shim will stall out against the side of the keyway and the key will slide past the shim.  So you have to withdraw the key and shims a few times and play around with how far into the keyway the shim is placed before driving the key home.  The goal is to have the shim in contact with full length of the side of the key. "

You have to read it all, clytle374

[clytle374]

Yep, actually I found some .005" brass shim in the tool box. I fit in both the shaft and the hub, a little surprised with the hub.  But again it is brass

I cut it longer than the key, and with ~the same taper.  I started it a bit ahead of the key it hit the taper and stopped, key followed suit shortly after with a nice "ping"

I already had the sharpie marker and the file thing down so I didn't take much time.  I am a little leery of the few thou won't matter, according to "calipers measuring crooked things" I was almost inside that.

You have to read it all, clytle374

I did, are you seeing something I missed? 

[clytle374]

Cool, just got the other one fitted and installed.

Hotater:  No disrespect intended with using the shims.  Not ideal, but I had been thinking it and couldn't think of why it wouldn't be safe.  Making keys to fit is the long term solution to the problem, but the cold/snow/no-heat-when-the-power-goes-out season is here.  I don't have much time starting a new job and all.
Next spring I had always planed on a a complete tear down, de-bondo,hot tank, and loving re-assembly. Now one more reason to do it.  Plus I figured some hours would help find the weak spots.   Oh yeah and some serious balancing. 

ANAL-I is alive again

[4x4_Welder]

At about 1:34 in this video, you will see the key installation method they use on the Indian engines.  BTW, production values and work quality seem about on par in this video-
http://www.youtube.com/watch?v=qE_EDxV_rRc

[dcamac1]

Has anyone ever tried Red Loctite?  Takes up to .030.  Seems like this would work temporarily. To disassemble just heat to appox. 120 deg. F. If this engine is going to be disassembled in the spring why not machine a new keyway on the crank?  Broach a new keyway in the flywheel, cut new Gibkeys and have confidence that the flywheels will not fall off.  Not trying to step on anyones toes, I'm new here and just asking a dumb question.