Manual Oil Pump

[Chris]

I have prepared a dimensioned sketch of the plunger and base assemblies of the manual pump to suit 2.3/4 hp machines from 1912 to EW. It does not contain 100% of the dimensions but I believe there is sufficient information to enable a working pump to be manufactured. The most difficult part to envisage is the "insert". This needs to be a slide in fit into the recess of the base. The 3/16" bore is a continuation of the bore of the base. This enlarges by means of a counter-bore to a clearance diameter of the non-return spring. The disk sits above the spring in the upper recess and seals against the "Lid" preventing air being pulled up into the pump when the plunger is raised. When the pump is full and under pressure from the spring the disc is depressed against the spring  and the oil then passes through the cut-outs, past the spring, into the bore and thence to the drip feed indicator before entering the engine. The non return disks and springs and the leather washers are available from the London Douglas Motorcycle Club to members of that club only. The missing dimension for length of plunger at the top of the sketch is 5.1/2". The length of 1/4"BSF thread on the plunger is 7/8". The threaded "Spool" at the base of the plunger screws up to the shoulder. The diameter of the top of the spool is just large enough to support the base of the spring but must clear the bore of the pump body. The smaller diameter can be the same as the support washer under the leather washers.



Larger view for screen display

Original drawing for printing - 200dpi, approx 25cm x 19cm (will fit on A4), 317kb

[gsx1100s]

Thank you for your drawings , I was wondering if anyone knows the leather thickness and type (is it important ? )for the washers used on the pump.

regards Michael

[Chris]

Hi Michael
   The leather washers for the oil pump being a soft and natural material vary in thickness but is usually about 75 to 80 thou. thick on the side walls.  They have to be pressed into a cup shape with a punch and die. They have a central hole of 1/4" diameter. The lower washer attached to the base of the oil pump needs to have its central hole opened out to 3/8" diameter. These washers already preformed are available from the London Douglas Motor Cycle Club for members of the club.   Chris.

[gsx1100s]

Thanks Chris , appreciate the information

regards Michael

[Dads24]

Thanks Chris , appreciate the information

regards Michael

Hi Michael, I went to my local pump shop and asked for 1" leather pump buckets- SOFT. Got 3 for $51 off a rega spray pump ,the hole is a bit big but the washer holds them in central enough. I gave mine a coat of engine oil before fitting. Regards John

[Chris]

Hi John
  The leather pump washers for the oil pump are available from the LDMCC at only £1.00 each. The savings from your $51.00 would have more than paid for your first year's annual membership of the London Douglas MCC . The washers always benefit from being kept well oiled and in an airtight container such as a 35mm film container when being stored to prevent them drying out. Chris.

[runmark]

Hello Chris,  I am in need of a complete check valve assembly for my 1924SW Do you make these or do you know of a supplier?  Thanks in advance.  Mark

[Chris]

Hi Mark
There is no Known source for these which is why I put the sketch up on the forum so that members can make them or get them made. The only parts that are available are the small spring and discs sold as a set from the LDMCC Spares Scheme, available to LDMCC members only. By making your need known on the Forum there is a chance that a second-hand item may be made available to you if someone has a spare in their boxes of bits. Good luck.
Chris.
 

[Bert]

I’ve just had to rebuild the oil pump on my 1913 2 3/4 hp. I found that the one way valve and spring at the base of the pump is missing, however the valve on the top of the crankcase is in place.  My engine has apparently been running for quite a few years in this guise.
I tried to unscrew the ‘lid’ but reckon I’ll break the slotted thread if I try any harder. Given that both one way valves work in the same direction between pump and engine, are two necessary?

[JR34]

Is there a part number for the Leather Washer from the club? 
Thanks

[Peter54]

Hello everyone, I'm wondering, where I can get the leather washers for my Douglas W21, when not a member of London Douglas Motorcycle Club. I am from Germany and being in the London Club doesn't really make sense for me. Any other sources where I can get those leather washers? Thanks Peter

[cardan]

Hi Peter,

The expression in English is "leather cup washer" and they seem to be readily available online, provided you know the size.

This ebay seller seems to have every available size so might be worth trying:
https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=leather+cup+washer&_sacat=0&LH_TitleDesc=0

Also, you can make them pretty easily - soak the leather in water for a day, press into a mold, and let them dry out - but it hardly seems worthwhile if you can buy the size you want.

Leon

[Peter54]

Thanks for your help.