Author Topic: douglas A32 350cc ? EW Timing Gear?  (Read 4557 times)

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Offline tom hoek

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douglas A32 350cc ? EW Timing Gear?
« on: 04 May 2012 at 18:23 »
Hello
 I have a question for you all
 Is the crankshaft gear of an A32 A31 is the same as that of an EW 350 cc
 or is not?
 Thank you for the effort :)

 Greetings from Tom Hoek



« Last Edit: 07 May 2012 at 07:03 by tom hoek »

Offline Alan

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Re: douglas A32 350cc ? EW Timing Gear?
« Reply #1 on: 09 May 2012 at 01:10 »
I currently have an A31 crankcase fitted to my B29 as the B29 crankcase needs a bit of work.The B29 is based on an EW but with a sump and oil pump....All the internal parts including timing gears etc from the B29 fitted straight into the E31 crankcase...As a side issue,some of the original timing gears were stuffed ( to use a technical term) so replacement gears were made by modifying gears from Brirish lathes etc as these used a similar tooth pattern...The use of these gears was discussed in quite a bit of detail some years ago in this forum. These gears are not hardened and had a chat with someone who had replaced his gears and then hardened these and wished he hadn't as eneded up with internal damage...

Offline tom hoek

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Re: douglas A32 350cc ? EW Timing Gear?
« Reply #2 on: 09 May 2012 at 20:05 »

Thanks for the response
 Go search on this forum after the discussion about the tooth wheels
 If I make a gear he'd better not hardened? If I understood correctly?

 regards Tom















Offline Daren W Australia

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too many dougli not enough time!

Offline tom hoek

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Re: douglas A32 350cc ? EW Timing Gear?
« Reply #4 on: 14 May 2012 at 06:49 »
Hallo All

Have I received this message from Doug    { Doug thanks  :)
Hello Tom,

I believe Alan is referring to these posts:
https://www.douglasmotorcycles.net/index.php?topic=2394.msg8695#msg8695
https://www.douglasmotorcycles.net/index.php?topic=901.msg2964#msg2964

However, they only reiterate old English lathes being a possible donor source for gears and pinions.

The technical specifications for the gear teeth are 18 Diametral Pitch, and 20 degree Pressure Angle.

It was also mentioned on the Forum that the gears should not be hardened. I would not agree in principle, though I might agree in practice. Originally they were case-hardened, a hard surface 'skin' on a tough, shock resistant core. Smaller gears (pinions) should be slightly harder than larger gears. But they should not be at maximum hardness. I aim for 48-58 on the Rockwell Hardness C-scale, depending on the size of gear and size of the gear tooth. Again, smaller gears (pinions) should be harder than larger gears. If you are not going to put extensive mileage (kilometers!) on the machine, you can substitute a non-hardend pinion. I have machine gears from pieces of truck axle shaft for a semi-hard pinion, but you need sharp cutters! I would be more comfortable if it were the cam gears that were soft, they have a greater number of teeth to spread the wear over.

I hope this translates adequately.

best regards,
Doug




 

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