Author Topic: Six interesting (?) Douglas (?) oil pumps  (Read 585 times)

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Offline cardan

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Six interesting (?) Douglas (?) oil pumps
« on: 06 Jun 2018 at 06:36 »
Can someone help with IDs for these pumps?

If I number them:
1 2 3
4 5 6

Number 1 is brass, and has a pair of full-width gears. Driven shaft has two flats, so could be shaft drive?

Number 2 is also brass, and is the only reciprocating pump. Drive is via a worm gear on the crank shaft? SW5 or similar?

Numbers 3, 4 and 5 are all similar: steel bodies with drive via a gear screwed onto the shaft. 3 and 4 have a delivery side and a scavenge side, but with slightly different inlet/outlet holes, while 5 has just one pair of narrow gears.

Number 6 looks to be new-old-stock, but made from Mazac (or similar) that has rotted and cracked before it could be used. The drive is similar to Number 1, as are the dimensions, but it's a two-sided pump. On the back (opposite the drive shaft) there is a one-way ball valve to let oil flow into the pump.

Douglas? Something else? Any suggestion welcome.

Cheers

Leon




Photo lighting modified - Dave, 6 June 2018
« Last Edit: 06 Jun 2018 at 08:23 by Dave »

Offline eddie

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #1 on: 06 Jun 2018 at 06:59 »
Leon,
          At a guess, I would say that 1 & 3 are probably Velocette pumps (I have seen them adapted for use on post war Douglases - not an easy job!!). Number 6 is definitely for a 1950's BSA single (B31-34 or C10/11).   Sorry, can't help with the others.

  Regards,
                Eddie.

Offline cardan

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #2 on: 06 Jun 2018 at 11:02 »

Thanks Eddie (and Dave for improving the photo).

Excellent. No. 6 is certainly boring BSA, and 3 and 4 seem to be Velocette. I'm still not sure about No. 1 and No. 5, but No. 2 is very similar to the SW5 pump discussed by Doug some years back: http://www.douglasmotorcycles.net/index.php?topic=4497.msg16113#msg16113

I hadn't realised that the gear-pump-in-cylindrical-body was so widespead in motorcycle engines. I see cammy Nortons used one, but with three gears sets - one delivery and two scavenge.

Cheers

Leon

Offline Doug

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #3 on: 07 Jun 2018 at 05:46 »
Leon,

#3 looks very much like the pump in my 1957 Velocette Venom. I had a broken ADT spring drop into the drive gear mesh on mine, so had an intimate look at it many years ago.  There were subtle variations, so I would say post war Velo.

#2 is I am certain is Douglas, but I am having trouble placing which model. Douglas made 2- and 3-stage versions of this pump. The 3-stage was for the recirculating oil systems. They are seen in bronze, and for the DT/SW5 in aluminum. The problem I am having with identification is the raised reinforcing lip around the perimeter. I have not seen that before.

-Doug

Offline Doug

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #4 on: 07 Jun 2018 at 05:48 »
The drive worm with it is interesting too. Usually these are part of the idler gear on the ohv models, or have a much smaller bore to spin on a post and dogs on the face to take the drive off the crankshaft nut.

-Doug

Offline Doug

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #5 on: 07 Jun 2018 at 05:51 »
3-stage bronze pump here, showing drive worm:

http://www.douglasmotorcycles.net/index.php?topic=4288.msg15399#msg15399

-Doug

Offline cardan

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #6 on: 07 Jun 2018 at 10:18 »

Thanks Doug. This one is only 2-stage - here's some more detail.

Leon

Offline bear640

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #7 on: 10 Jun 2018 at 12:47 »
No1 looks very similar to BSA sloper models?

Offline cardan

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #8 on: 10 Jun 2018 at 23:11 »

Brilliant: No. 1 BSA Sloper. Tick.

So it's down to identifying the only Douglas pump! The drive worm is 7/8" inside diameter, with just a tiny taper on it, no keyway. Of course it may not be Douglas after all...

Cheers

Leon

Offline Doug

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #9 on: 10 Jun 2018 at 23:37 »
Oh, definitely Douglas.

Attached are pictures of the small airbox DT/SW oilpump. As you can see, even the oil circuits look the same, so good chance it will fit. I have just not seen one of these in bronze and with the reinforcing lip. It might be an early iteration, improved later version, or someone cast new bodies (JN?) in bronze to use original Douglas hardware.

I also note there is a slight variation in the bypass check valve.





-Doug

Offline cardan

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #10 on: 11 Jun 2018 at 12:46 »
Yep, I guess it could be an Aussie-made version of the DT pump - we had DT's running until after WW2 and a history of making knock-off spare parts. But the pump in your photo is not worm drive? Or is it just an optical illusion.

Leon

Offline Doug

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #11 on: 11 Jun 2018 at 20:46 »
Leon, 

It is worm drive. The worm is integral with the timing idler gear.



-Doug

Offline cardan

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Re: Six interesting (?) Douglas (?) oil pumps
« Reply #12 on: 11 Jun 2018 at 22:45 »

Thanks Doug. The taper on my worm is so slight that I suspect it is designed as a press-on interference fit, so perhaps the whole thing is a replacement part - machine off your old worm, press this one on.

At least one of the pumps is Douglas! Thanks everyone.

Cheers

Leon

 

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