1920 Cadillac starter/generator bakelite coupling

[Matthew Hinson]

Hi All,

 

 I need to replace this bakelite piece that is attached to the shaft in front of the starter/generator. I've got it J.B.Welded and on the shelf until next weekend, but I'd rather have an intact one. I checked my parts bin and no luck.

 

The car is a 1920 model 59 touring 7 pass.

 

Thank you,

 

Matthew

[Restorer32]

Are you sure it isn't fiber rather than Bakelite?

[Matthew Hinson]

It's hard phenolic. It doesn't look like it was ever a flexible material like a rag joint, though that type of material would probably work. If I find a replacement that is made out of fiber that would be fine, as long as it fits.

[Grimy]

I'm no expert on Cads of this vintage, but if fiber "rag" joints will work, John Cislak in MA at 413-five-forr-tree-9017 sells them very reasonably in at least two sizes for Pierce-Arrows.  He'll need OD, center hole diameter, bolt on-center measurement, bolt diameter.  He says he only checks email once a month, so I'm not listing that.

[Matthew Hinson]

Thanks, that sounds like a good solution. I'll give John a call.

[Gary_Ash]

It's probably made of canvas or linen phenolic - sheets of cotton fabric impregnated with phenolic resin and cured.  I'm not sure why they would have used a rigid plastic-like material instead of a flexible rubber/fiber sheet or belt.  If you want a new one like the old one, get some grade L or LE phenolic from McMaster-Carr or MSC.   The L/LE grade is just a little more expensive than the C/CE grade but LE can be machined to close tolerances with a smoother finish.  A 12"x12"x1/4" sheet is about $25, available in multiples of 1/16" thickness.  It machines easily but is stinky.  Take your old part and the new phenolic sheet to any machine shop and they can make a new one for you.  It would help to bring the mating metal coupling so they can get the hole spacing exactly right.  If you're handy with a jigsaw and drill, you can make it yourself.

 

See https://www.mscdirect.com/industrialtools/phenolic-laminate-sheet.html

[Marty Roth]

Matt,

 

I think Mark Shaw had found a source for this part (at least for the Delco Starter/Generator on Buicks) - maybe it was available on ebay?

Check with him?

[Joe in Canada]

Very easy to make as you can use a hand held coping saw very little cost under &10.. Then again you could go into mass production and corner the market under $100 with a powered unit. If they can make an intricate tree from wood you should be able to cut out your part.

 

Edited November 27, 2017 by Joe in Canada (see edit history)

[hidden_hunter]

If it’s the part I’m thinking of its metal on the type 61 (and was possibly an interchange part)

 

I’ll be back in Australia with my cad next week and can take measurements for you from my type 61 5 passenger coupe 

[Matthew Hinson]

Ok thanks everybody! Btw, I picked up a load of 1922 Cadillac parts including 3 starter generators. It looks like most things interchange. None of the starter generators have this piece. They do have a grease tube for lubrication that mine does not have. That must have been an upgrade for the 61

[hidden_hunter]

16 minutes ago, Matthew Hinson said:

Ok thanks everybody! Btw, I picked up a load of 1922 Cadillac parts including 3 starter generators. It looks like most things interchange. None of the starter generators have this piece. They do have a grease tube for lubrication that mine does not have. That must have been an upgrade for the 61

 

They did a lot of upgrades on that area of the motor, the top cover Is also redesigned almost every model year. It wasn’t fixed until the v63 and will disintegrate if you have a stuck valve 

[Ivan Saxton]

It did not look right to me Matt,   I suggest it is a modification by Rube Goldberg, as Jerry Gebby would probably advise you if he was still about.  The correct rings are  60 thou thick steel sheet,  2.500 inches outside diameter, and 1.500 inches inside diameter.

The two sets of holes are at right angles.  They seem to have gone to a lot of trouble to make it wrong.   In the mid 1960s, we had a talk at the Vintage Drivers' Club in Melbourne by Phil Irving, who had designed the extraordinary Vincent racing motorcycle engines; and later  designed the F1 champion V8 Repco Brabham engines, which were developed out of an aluminium alloy Buick production engine block casting.  Someone asked Phil a question about altering engines. His advice was, that you may go to a lot of trouble to change things; and you are likely to find that the designer was right in the first place.  If you need to run with those broken Bakelite  discs, tighten a screw-thread drive radiator hose clip around the outside.  All the best,  Ivan

[Friartuck]

Gary Ash brings up a good point on flexing of this coupling. In that spirit, may I suggest machining it out of Delrin. It machines beautifully and offers slight flexing. Bill in Pittsburgh area sells surplus Delrin and Nylon in large sizes. Some may have seen him in the Green Field at Hershey. His number is 412-977-5279. He offers thick sheet and round stock.

Edited November 29, 2017 by Friartuck (see edit history)

[Ivan Saxton]

The original rings of 1/16"steel sheet give exactly the correct flexibility.   The shaft and couplings only drive the generator function of the dynamotor, which is not a heavy power load.   Thermo-plastic plastics are not a good choice in proximity to those hot exhaust manifolds in the V between the cylinder blocks,  and the exhaust from a low compression ratio L-head without Rickardo combustion chamber design has to get rid of more waste heat than from a later engine.

[emjay]

7 hours ago, Ivan Saxton said:

It did not look right to me Matt,   I suggest it is a modification by Rube Goldberg, as Jerry Gebby would probably advise you if he was still about.  The correct rings are  60 thou thick steel sheet,  2.500 inches outside diameter, and 1.500 inches inside diameter.

The two sets of holes are at right angles.  They seem to have gone to a lot of trouble to make it wrong.   In the mid 1960s, we had a talk at the Vintage Drivers' Club in Melbourne by Phil Irving, who had designed the extraordinary Vincent racing motorcycle engines; and later  designed the F1 champion V8 Repco Brabham engines, which were developed out of an aluminium alloy Buick production engine block casting.  Someone asked Phil a question about altering engines. His advice was, that you may go to a lot of trouble to change things; and you are likely to find that the designer was right in the first place.  If you need to run with those broken Bakelite  discs, tighten a screw-thread drive radiator hose clip around the outside.  All the best,  Ivan

I've seen couplings like this but aren't they made of two .060 thick rings where the bolts only attach to the nearest ring and of course the two rings must be fastened to each other in between the bolts with either rivets or bolts?  Of course the two rings do not lay flat because they need to go over the bolt head.

[Ivan Saxton]

I have an original drive shaft with one 1/16" thick ring on each end beside me on the computer desk.  It has been removed from the engine of probably my Model 61 by a previous owner. ( The starter-generator shaft will not turn, but the engine turns over by hand.  It is sometimes considered beneficial to maintain oil on the surface of cylinder bores of an engine that has not run in a long while.)   That shaft is 12 inches long, and the inside diameter I measured locates the shaft accurately on the matching couplings on the engine at the front, and on the starter/generator at the back.

[Matthew Hinson]

Thank you Ivan,

 

I'm going to pick-up again with this project when the weather breaks. I'll measure my driveshaft and see if it is the same.

 

Best,

 

Matt

[Friartuck]

I think Ivan is correct in suggesting thin disks cut round and profiled inside as shown. Two disks are used on model L Lincolns on each end of the coupler shaft. Perhaps make them out of Stainless which would polish up nice. On the bolt pic, notice the shaft is right up to the bolt head which goes through the disks first allowing the disks to turn on a solid round surface.

Edited January 12, 2018 by Friartuck
pics added (see edit history)