fan hub fix - Good Grief

John Z · August 14, 2015, 06:44:46 AM

I dropped off my 4104 fan hub at a machine shop last Friday. I asked the owner if he could weld it up solid and balance it. He said yeah, they could do that. Yesterday they call and say its ready. I go to pick it up, and when she sets it down in front of me, it just didn't look right. After I pick it up to chk it out, I see they have welded it together backwards!!! They reversed the inner sleeve! The hub for the blade and the keyway for the crank are on the same end! I show it to the guy who welded it, and he's like, "yeah, that's how it was when I got it!". He offers to cut it apart and redo it. I question how well balanced its going to be after that. "Balance! We can't balance it." I speak to the owner and ask him about the balancing. He chuckles a bit and says they can kinda balance it. "Kinda? Its either balanced or it isn't, no kinda about it!" He says they will cut it apart and fix it right them. Will take 20, maybe 30 minutes. 45 minutes later the lady says their working on it. "I hope so, it was supposed to be done 15 minutes ago. How much longer?" She says she has no idea. <crickets> "Could you find out?" She comes back and says its going to be about a half hour. I had to leave to get home to be with my granddaughter. I wonder what I will find when I get back there today?

eagle19952 · August 14, 2015, 02:31:20 PM

should have taken it to drive shaft shop.... it might not be too late

John Z · August 14, 2015, 02:59:10 PM

Never thought of that. I picked it up and dropped it off at the shop where my bus is. The head of the shop thought it looked pretty good.

gg04 · August 15, 2015, 09:46:02 AM

It has to be true with the crank!!! And has to be balanced ,otherwise it will eat fans.rdw

Hard Headed Ken · August 16, 2015, 08:16:55 AM

John if you're going to mount a fan on that hub I can tell you form experience that a fan, plastic or metal won't last very long before it disintegrates mounted directly to the crankshaft. That's why it had an isolater from the factory.
The fan with the adjustable blade pitch will be a little better because you can at least keep a check on the bolts that hold the blades in. I can't think of the name of that fan, maybe Wing something.

Ken

gg04 · August 16, 2015, 02:54:13 PM

Different experiences I guess. Mine has been solid mounted for over 13 years and 100,000 miles. Works for me. rdw

John Z · August 16, 2015, 03:08:04 PM

Well the machine shop said it ran true. I guess how could it not? They sleeved the two pieces and pressed them together, then welded it. I will ask the shop foreman if he thinks I should pursue further balancing. The blade I ordered is a metal hub with nylon blades.

Hard Headed Ken · August 16, 2015, 03:18:33 PM

My failure may not have been caused by the solid mount hub. I always blamed the solid hub because after it failed I read somewhere that any fan should not be mounted directly to crankshaft because of the vibrations produced by the diesel combustion process. I put the variable pitch fan on before I sold it and the current owner says he has to keep a check on the bolts that hold the blades in the hub. I think Uncle Ned has this style fan and like my old 4104 it also has a 6V92 so I'm really not comparing apples to apples. Of course the 671 is a very different engine.

A plastic fan with a metal hub is the style that failed on mine and took out the radiator.

Ken.

luvrbus · August 16, 2015, 03:37:06 PM

The GM buses with a direct fan drive use a rubber isolator we ran into that when Red Ryder had all the parts made for his,we were advised by Luke and Chris not to use the direct drive without the rubber coupling so we went back to fluid drive.

LOL I see Mikes $$$$ worth of machine parts in my shop daily

Red Rider · August 16, 2015, 06:11:02 PM

Clifford,
We left those parts so you could tell other folks not to do what I attempted. Those GM engineers knew a little more about engine cooling than I do. Thanks again for saving my bacon.

pvcces · August 16, 2015, 06:48:32 PM

Clifford, we are trying to work in a fall trip to get the torus rebuilt. I'll let you know if we get it figured out.

Tom Caffrey

uncle ned · August 17, 2015, 07:06:17 AM

I think we need John Vickery in on this.

Our friend from Costra-rico that had all the GM insigna's made was trying to find some fan hubs to have reworked
in his home country.

uncle ned

John Z · August 17, 2015, 07:33:37 AM

The garage just called. I expected him to say it was back together and to come pick the bus up. But things have gone from bad to worse. He started to put it all together. It would only slide on the crank about 2". He gave it a couple light taps, and if didn't budge. So he pulled it off, the weld broke and the inner sleeve pulled out about an inch! How did they shrink that inner sleeve?

gg04 · August 17, 2015, 08:50:52 AM

Clifford what happened to Mikes? Mine has been welded sold since before I changed engines. Am I just lucky? rdw

luvrbus · August 17, 2015, 09:46:38 AM

Nothing happen we didn't install the pcs,Mike bought a engine from a 4107 that had a direct drive with the clutch and isolator the problem only the direct drive came with the engine less all the parts from the drive out and there was no parts to be found

Someone told him the torus setup would not work on the engine so he began having parts made ,he went home for the week end and I removed all the parts and install his torus fan setup and he has been happy, he had a valve problem but repaired it all has been well since I guess he never called ragging on me.

Mikey and Tom Caffrey are my favorite bus people nothing excites those 2 my type people

lol the GM people seem to have adopted me for some reason GM people are rare breeds I enjoy the GM people