Has anybody had experience swapping a 1911 style narrow Transmission Brake Drum to the wider 1926/27 style?
From what I can see, you would need to retain the narrow band but how about just the drum alone?
It is difficult to find a useable early Drum that isn't cracked or chewed out due to the outer legged clutch plates wear.
Ideally, the later Drum with the steel collars to prevent clutch plate wear would be a great outcome if it would fit
Can you give advice or link to a previous thread on this subject
Thank you guys and Happy Australia Day to us Aussies.
Alan in Western Australia
I've done it for a 1912 car with a 7 rivet pan and aluminum hogshead. I cut down the width on a lathe to where it just overlapped the driving plate. Having steel shoes to protect the lugs and a captured driving plate were two benefits. I believe someone stated in an earlier post that you didn't have to cut down the drum to fit but had to use a narrow band. I never tried it that way, thinking it needed to be narrow to fit the pan and hogshead.
Snce the pan on the "improved" cars was relieved to provide clearance for the new wide drum and band, I'd be concerned about clearance in an earlier pan without cutting down the drum, even with a narrow band. This was discussed not long ago, some responses indicated it's not a problem. ??
I checked it out in a previous discussion. Look at a narrow brake drum together with its drive plate - the hinges for the clutch arms are just about as far out and back as the rear edge of a wide drum. On the drive plate from the wide drum, the hinges are moved to the center and the drive plate has a smaller diameter so it fits inside the drum. Clearance to a three dip pan should be about the same for both, while there isn't enough room for a wide brake band in a three dip pan.
No need to cut a wide drum, then.
you also need the later clutch plates
Alan, A few points.
I believe the wide drum will fit without modification, but you must use a narrow band. The wide band will not clear the pan, and the pedal spacing in the hogshead will not line up with the wide band anyway.
With the wide drum you also need the clutch driven plate to suit. The narrow drum plate will not bolt up to the wide drum.
As Peter K mentioned, you will need the later hexagonal clutch discs to match the lugs in the drum.
I have just this set-up in my 1925 roadster. I chose to machine some off the width of the drum, but it is still wider than the original narrow drum and the edge of the driven plate. The advantage is the band has one continuous surface on which to engage, rather than the original two surfaces, often mismatched.
Hope this helps.
Allan from down under.
Alan: We make new transmission drums if you didn't know.
The drums we make have the later style design for clips. These are made exactly to FORD prints.
You can take a wide drum and turn it down to a narrow size
Thank you for the replies. I should have my transmission out of the vehicle soon to assess the damage in this area
The real problem is the bolts stick out the back of the wide drum and will hit an original pan.
Then too, the shaft spacing is different between the low speed shaft and brake drum shaft to center the band on the wide drum.
Ok, maybe the long style of bolt may touch a three dip pan? Maybe they do go a little further out than the clutch arms on a 26/27 driven plate? I'm using the early '26 style screws that stays inside the drum. When using the narrow band with a pre '26 hogshead the brake band will work in the same area as on a narrow drum -if the drum is wider behind doesn't really matter
(Message edited by Roger K on January 28, 2017)