Oil pump scavange gear question

ES234

VIP MEMBER
Joined
Apr 5, 2014
Messages
45
Country flag
Oil pump return gears 0.407.JPG


I have been trying to sort out some pump parts over the last few days and have a question. Having refurbished/reconditioned probably a couple of dozen Norton oil pumps over the years (predominantly from singles, but also some Dominators and Commandos), I thought I had most the answers to these things, but have temporarily stumped myself. I do not at present have a complete Commando pump to resolve this question.

  1. A single (ES2, Model 18, Big 4, 16H) pump body has the timing cover outlet at the top as fitted, while the twins have this at the bottom. The twin e.g. Commando pump hence has the return gears at the top of the body. and the single at the bottom.
  2. I understood that all the twin oil pumps irrespective of the model, have one of the wide oil return gears intergral with the pump drive spindle.
  3. However, I have a couple of pairs of these late model return gears (0.407" wide), each of which one gear of the pairs has the internal drive "tangs" and therefore from the "bottom side" of the pump.
Can somebody please resolve my confusion. I am sure the answer is obvious, just not to me at present.

Geoff
 

robs ss

VIP MEMBER
Joined
Aug 16, 2016
Messages
1,540
Country flag
View attachment 81094

I have been trying to sort out some pump parts over the last few days and have a question. Having refurbished/reconditioned probably a couple of dozen Norton oil pumps over the years (predominantly from singles, but also some Dominators and Commandos), I thought I had most the answers to these things, but have temporarily stumped myself. I do not at present have a complete Commando pump to resolve this question.

  1. A single (ES2, Model 18, Big 4, 16H) pump body has the timing cover outlet at the top as fitted, while the twins have this at the bottom. The twin e.g. Commando pump hence has the return gears at the top of the body. and the single at the bottom.
  2. I understood that all the twin oil pumps irrespective of the model, have one of the wide oil return gears intergral with the pump drive spindle.
  3. However, I have a couple of pairs of these late model return gears (0.407" wide), each of which one gear of the pairs has the internal drive "tangs" and therefore from the "bottom side" of the pump.
Can somebody please resolve my confusion. I am sure the answer is obvious, just not to me at present.

Geoff
Geoff
Unless I'm going crazy too (a distinct possibility) the answer is that the tanged gear goes onto the driven (bottom) shaft while its mate meshes with it on the undriven (top) shaft on the same (deep) side of the pump.
Does this answer your question - or have I not understood your issue?
Cheers
Rob
 

robs ss

VIP MEMBER
Joined
Aug 16, 2016
Messages
1,540
Country flag
Sorry - that's rubbish above.
I see your issue - the thick, tanged gear should actually be part of the input shaft.
I wonder if Norton had some pumps where the thin (pressure) gear was part of the input shaft - meaning one of the thick (scavenge) gears would have to be tanged?
Hopefully someone, maybe @L.A.B. , will come to the rescue.
Cheers
Rob
 

ES234

VIP MEMBER
Joined
Apr 5, 2014
Messages
45
Country flag
Geoff
Unless I'm going crazy too (a distinct possibility) the answer is that the tanged gear goes onto the driven (bottom) shaft while its mate meshes with it on the undriven (top) shaft on the same (deep) side of the pump.
Does this answer your question - or have I not understood your issue?
Cheers
Rob
That is what is logical, however I don't have a twin pump at hand to look at, and the John Hudson oil pump article infers that the (wide) return gear is fixed on the shaft (as I read it) . Don't worry, it feels like a seniors moment for me.
 

Attachments

  • John Hudson Oil Pump Reconditioning #1B.jpg
    John Hudson Oil Pump Reconditioning #1B.jpg
    458 KB · Views: 12

gortnipper

VIP MEMBER
Joined
Nov 11, 2013
Messages
4,342
Country flag
View attachment 81094

I have been trying to sort out some pump parts over the last few days and have a question. Having refurbished/reconditioned probably a couple of dozen Norton oil pumps over the years (predominantly from singles, but also some Dominators and Commandos), I thought I had most the answers to these things, but have temporarily stumped myself. I do not at present have a complete Commando pump to resolve this question.

  1. A single (ES2, Model 18, Big 4, 16H) pump body has the timing cover outlet at the top as fitted, while the twins have this at the bottom. The twin e.g. Commando pump hence has the return gears at the top of the body. and the single at the bottom.
  2. I understood that all the twin oil pumps irrespective of the model, have one of the wide oil return gears intergral with the pump drive spindle.
  3. However, I have a couple of pairs of these late model return gears (0.407" wide), each of which one gear of the pairs has the internal drive "tangs" and therefore from the "bottom side" of the pump.
Can somebody please resolve my confusion. I am sure the answer is obvious, just not to me at present.

Geoff
Did you see my post in your other thread on this with the link to SD's video? ?
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
16,689
Country flag
I have a couple of pairs of these late model return gears (0.407" wide), each of which one gear of the pairs has the internal drive "tangs" and therefore from the "bottom side" of the pump.

Return gears from single cylinder pumps.
 

ES234

VIP MEMBER
Joined
Apr 5, 2014
Messages
45
Country flag
Sorry - that's rubbish above.
I see your issue - the thick, tanged gear should actually be part of the input shaft.
I wonder if Norton had some pumps where the thin (pressure) gear was part of the input shaft - meaning one of the thick (scavenge) gears would have to be tanged?
Hopefully someone, maybe @L.A.B. , will come to the rescue.
Cheers
Rob
That is correct, and the gears that I have are 0.407" wide scavenge or return gears and separate to the input shaft.
 
Joined
May 12, 2011
Messages
58
Country flag
From Hudson's notes I assume its just terminology, integral gear but he doesn't mean machined one piece sort of thing.
otherwise how could the body come apart.
Screenshot-2021-07-20-021000-jpg.png

pump.jpg
 

ES234

VIP MEMBER
Joined
Apr 5, 2014
Messages
45
Country flag
Return gears from single cylinder pumps.
Just like every single (OHV/SV) pump 0.190" feed and 0.314" return (approx) gears. The single has the feed gear on the shaft as pictured and the twin (Dommie/Commando) the return (wide) gears. So my question/dilemma is what are the separate 0.407" gears I have pictured? :)
 

ES234

VIP MEMBER
Joined
Apr 5, 2014
Messages
45
Country flag
From Hudson's notes I assume its just terminology, integral gear but he doesn't mean machined one piece sort of thing.
otherwise how could the body come apart.
Screenshot-2021-07-20-021000-jpg.png

pump.jpg
To take the body apart you lock up the drive gear in some narrow soft jaws, undo the top nut, remove the drive gear using a puller, remove the key and slide the shaft out. I have done quite a few as necessary when reconditioning these pumps. Om assembly the drive gear can be reversed from memory to provide an unworn drive face.
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
16,689
Country flag
Just like every single (OHV/SV) pump 0.190" feed and 0.314" return (approx) gears. The single has the feed gear on the shaft as pictured and the twin (Dommie/Commando) the return (wide) gears. So my question/dilemma is what are the separate 0.407" gears I have pictured? :)
The pump gears in my picture measure (approx.) 0.187" feed and 0.404" return.
 

ES234

VIP MEMBER
Joined
Apr 5, 2014
Messages
45
Country flag
Thanking you L.A.B. This solves 99% of my real problem as to a source of these gears.

It does however leave me confused as to what these gears are from (of which I have a couple of damaged sets) when the Norton twin oil pump is described as having the return (0.406/0.407" wide) drive gear fixed on the pump drive shaft? This is no more than a seniors moment, and hence for me at least, frustrating as I know I have sorted all this out years ago without over thinking it. :)
 
Last edited:
Joined
Jan 19, 2012
Messages
1,145
Country flag
Opps. I just noticed LABs measurement. Norton fitted really wide gears for the scavenge side of pump type 15521 (this would be for the 1960-63 models). It's surprising, albeit a rational use of existing parts (the dogged gear wheel is special though).

-Knut
 
Last edited:

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
16,689
Country flag
It does however leave me confused as to what these gears are from (of which I have a couple of damaged sets0 when the Norton twin oil pump is described as having the return (0.406/0.407" wide) drive gear fixed on the pump drive shaft? This is no more than a seniors moment, and hence for me at least, frustrating as I know I have sorted all this out years ago without over thinking it. :)

The wide scavenge/return gears in my photo of what I believe to be a 'single' pump are the 'dogged' and 'idler' gears which are at the endplate side of the pump unlike the 'twin' pump which has the feed gears at the endplate side, therefore, a dogged 0.406"/0.407" gear has to have come from a 'single' pump.

According to dyodave...:

"late pump gear width-feed.250"/scavenge.416" (measured .401.406.412) feed-scavenge ratio 1.666

early pump gear width-feed186"(3/16")/scavenge.312"(5/16") feed scavenge ratio 1.666

dunstall
early pump gear width-feed186"(3/16")/scavenge .416" feed scavenge ratio 2.236"

...which seems to be for 'twin' pumps.
 

ES234

VIP MEMBER
Joined
Apr 5, 2014
Messages
45
Country flag
The wide scavenge/return gears in my photo of what I believe to be a 'single' pump are the 'dogged' and 'idler' gears which are at the endplate side of the pump unlike the 'twin' pump which has the feed gears at the endplate side, therefore, a dogged 0.406"/0.407" gear has to have come from a 'single' pump.

According to dyodave...:

"late pump gear width-feed.250"/scavenge.416" (measured .401.406.412) feed-scavenge ratio 1.666

early pump gear width-feed186"(3/16")/scavenge.312"(5/16") feed scavenge ratio 1.666

dunstall
early pump gear width-feed186"(3/16")/scavenge .416" feed scavenge ratio 2.236"

...which seems to be for 'twin' pumps.
All good, and thank you for your time and patience.
Just FYi the single pumps that I am familiar with, have 0.191" (nominally 3/16") feed gears, and 0.314 (nominally 5/16" return gears. I have rebuilt many single pumps, and never noticed the 13/32" return gears. That does not mean that I was simply not aware that different widths existed over all these years.
 
Top