Author Topic: Gearbox numbering  (Read 325 times)

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Offline saluki42

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Gearbox numbering
« on: 08 Jul 2020 at 17:10 »
Hi there I have at last got to the bottom of the boxes which comprise my 34 Model Z, with some worrying finds, but there is one puzzle I could do with some help with. The engine and frame number match what I would expect however the gearbox is the problem as the only numbers I can find comprise of a letter 'K' in a Letter 'D' followed directly by 'V2' then slightly further to the right and upside down are 'D1' followed at a short distance by a capital 'P'.
Could anybody enlighten me, is this possibly the correct gearbox for my Model Z?

Offline eddie

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Re: Gearbox numbering
« Reply #1 on: 08 Jul 2020 at 18:24 »
According to Jeff Clew's book of the Douglas, a 4 speed handchange gearbox with an E/ was listed for the Z & Z/1 models. A later 4 speed handchange gearbox prefix P/ was listed for the 1935 600sv & 750sv models. Around this time, some gearboxes had stub teeth and others had involute form teeth, so individual gears may not be interchangeable between boxes.

  Regards,
                Eddie.

Offline Doug

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Re: Gearbox numbering
« Reply #2 on: 08 Jul 2020 at 22:06 »
Full rundown on the applicable gearbox prefixes are this:

D/  1934 Z (Wessex), Z1 (Powerflow) foot-change
E/  1934 Z (Wessex), Z1 (Powerflow) hand-change

J/  1935 Z (Wessex), Z1 (Powerflow) hand-change
L/  1935 Z (Wessex), Z1 (Powerflow) foot-change

P/  1935 600 & 750cc , 4-speed, hand-change, involute
Q/  1935 600 & 750cc , 4-speed, foot-change, involute

The superimposed DK is the Douglas of Kingswood trademark. The V2 is some sort of inspection mark; you find them on engine cases too. The trans number is stamped on the top face of the inner end cover and not on the transmission case. The format should be the prefix, slash, and a three digit serial number. While this is not a Z/Z1, it shows the location and format:




-Doug

Offline saluki42

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Re: Gearbox numbering
« Reply #3 on: 09 Jul 2020 at 15:35 »
Thanks Eddie and Doug, I'll have to look in the boxes for the other gear boxes to see what other parts are there to try to find a number

Chris

Offline saluki42

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Re: Gearbox numbering
« Reply #4 on: 09 Jul 2020 at 16:48 »
Hi Doug a quick follow up to your reply.
I've had a look at the inner gearbox cover and the number is "6Q/220" which seems to indicate a 1935 600cc with foot change however, the gear selection is operated by rack and pinion through the top of the gearbox. Did they use the same system for both hand and lever change models?

Chris

Offline Doug

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Re: Gearbox numbering
« Reply #5 on: 10 Jul 2020 at 17:16 »
Chris,

They just altered the end covers which contained the gear change mechanism. Both hand and foot shift ended up operating a rack in the inner cover that turned the gear selection drum inside the gear case proper. I had a look to see if they used the same inner cover for both and perhaps someone has just swapped the outer cover. I have a 1935 foot shift gearbox on a ohv model, and while essentially the same gearbox turned ninety degrees and mounted up under the saddle, sharing many the same parts, am not certain the end covers are exactly the same as the side valve models. Pictures of the foot shift on the Z and Z1 are rare, so I could only find the 1935 catalog image. But it does look like the foot shift cover was much larger and a different outline than the corresponding foot shift version (like the ohv hand- vs. foot-change), so it does not appear you can mix inner and outer covers. Which leaves me a bit baffled! I did check the gearbox code list in the appendices of Jeff Clew's book "The Best Twin" to see if I accidentally got the codes reversed. I did not, but I have noted a few other errors in the list before. Anyone else want to chime in? 

1935 model Z (Wessex) with foot-shift:



1935 model Z1 (Powerflow) with hand-shift:




-Doug

 

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