Clutch Plate Surfacing

[Larry Zimmer]

Paul Van Oss asked me if I would post this for him. I unique method that he devised to refinish clutch plates. Neat!

I ground the alternator clutch disks on my lathe as per pictures.
I made a mandrel to press fit the disk on in my lathe. Checked runout before grinding and after. I was surprised on the runout before grinding!
Anyways I mounted everything back on the engine but without the outer alternator housing so I could check the friction between the disks.
I was surprised how little effort it took to turn the rotor with a wrench.
Any body know what kinda torque this system should support?
I think this is a nice way to check .
By adding shims we could get it perfect to the disinter torque.
My spring was exactly 30mm.

Also, a video, from icloud, of Paul's process.
https://www.icloud.com/attachment/?u=ht ... z=89029127

[Jeff Bennetts]

I wonder if he remembered to chamfer the oil groves?

[NobleHops]

That is in fact important. Without that the edge gets sharp, bits break off, and then grind fresh grooves in the newly ground surface, The stock spring length is 31 mm as new, we restore proper preload with arbor shims purchased from McMaster-Carr. The depth of the oil flinger grooves are 1mm - that is also restored so we don’t build up too much oil pressure between the clutch plates and float the clutches in high-pressure oil.

[Paul Van Oss]

Thanks guys for the follow up information.
Paul.

[wessi]

Very good idea, grinding on the lathe insted reguler turning. Also checking the tension without alternator housing is a great, i will try this.
But according the surface, as far as i know the OEM steel disks are not flat, when new, they are crowned, what would mean less tenion comming from the spring is needed for contact grip. If it´s flat, now, you need more tension, what is negative for the roller bearings of the alternator. My plan is to glue a friction plate onto on surface to avoid further steel wear particles in the oil circuit. Just ordered glue, Beral 1122 friction material and already machined the plates on my Lathe.

[Paul Van Oss]

I was just looking at friction and clutch material also. I think that is the way to go.
I seen a you tube video on this not to long ago, can not remember where .
Thanks Paul.

[NobleHops]

Cary Knapton of the SuoerSport Shed is creating these with friction material and reporting good results. He’s in the Uk.

https://thesupersportshed.com/

[Paul Van Oss]

Very interesting!
Thank you Nils.

[Larry Zimmer]

The slight crowning is to assure contact towards he outer edge of the plates. Preload is preload. The farther out it is the more torque for the given amount of preload. For steady state operation, more torque is required to overcome operating friction losses than is needed to generate charging current. If I remember correctly, the output is only 250W. (1/3 hp) Piddling! Need more torque to accelerate the rotor and overcome other friction in the system. Whatever you do, don't run the plates dry after refinishing. Those are cast iron. The friction between two nice dry cast iron plates will just ruin all good work.

[Jeff Bennetts]

Nice explanation Larry, very comprehensive yet simple to grasp!

[NobleHops]

Honda calls for moly lube on the plates at service, so we do. The last bike did not appear to be charging at first, which we put down to the lube, once some hot oil got in there everything was peachy keen and there was no chirping from the alternator either.

Did I share this in this thread yet? I miss my memory. We geeked out on alternator service a year or so ago and write up this tutorial here. No login needed:

https://www.facebook.com/media/set/?set ... 436&type=3

[daves79x]

I know Cary from GB is resurfacing the clutch plate with fiber and has apparently had success. Frankly, the jury is still out for me on that. I've seen some horrific things happen to these alternators and clutch plates that resulted in welding-level heat being generated. If all stays well with the alternator bearings and the spring is good and shimmed properly, it will probably work fine. I'm also a little leery of the fiber coming loose after many miles of service. I guess time will tell.

Dave

[daves79x]

I've always questioned the need for moly on the clutch plates upon re-assembly. If you turn your engine over with just the starter to build oil pressure after the re-build, you are putting normal oil pressure to the alternator clutches in the process of that. So what's different from any other start-up as far as the clutch plates are concerned? I've never done the moly thing and I've rebuilt a few with success.

Dave

[Jeff Bennetts]

I use a thin coat of engine assembly Grease, I’ve read that moly based grease can attack copper after it breaks down, this assembly grease has been around forever and is used in many industrial engines.

5B895472-BC85-4590-A8CA-06B856F0EFBA.jpeg

[Larry Zimmer]

Do as you mention, Dave, and I expect all should be well. Once oiled, the cast iron will always have something in its porous surface.

My concern with using a 'friction' material would be having it get into the oil. Yes, clutch plates are a material. However, they are not the type to pull off into the oil. Guess I don't know enough about the materials that are being considered, here.