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1936 16H oil pump required



A friend of mine has a very original oily rag 1936 16 H,which,up until recently was in regular use,until it suddenly started wet sumping very badly.

Upon removing and stripping the oil pump,it was evident that the body had corroded,and literally fell in bits in his hand.

Do any members with early singles experience know whether a pump from another model will be a direct fit,or,if not,does anyone have a serviceable pump that they would be willing to sell?

Many thanks - Rob



Will give a definitive answer, but Andover Norton do list brand new single cylinder oil pumps, at £183+VAT. Expensive maybe, but no wet sumping for a good few years if you go that route.

Regards,  George. 


I've only heard good things about the Andover pump which is steel bodied as per the twins. There were some small differences in the timing cover and pump castings so it's possible that a little easing may be needed but the 1936 bottom end is the same casting as the WD16H and they seem to fit those with no extra work.

In reply to by richard_payne


Hi Richard,

Many thanks for that info - it is very helpful & much appreciated! Obviously,improvisation is what makes classic bike ownership the fun that it is...! Regards - Rob

I would not normally wish to pour cold water on our resident 16H expert’s opinion that only good things have been reported on the Andover oil pump but feel it necessary to add my own findings for what they are worth.  They relate to the purchase of an AN Singles pump a few years ago.

 Amongst my Nortons I have a couple of 16Hs, a 1936 one and a 1940-ish WD.  Despite its 84 years, the early one hardly wet sumps at all, even after a few months non-use there is only an inch or so drop in oil level, I've never had to drain the sump before starting.  The WD however after a couple of weeks would spill its guts onto the garage floor if it had been left on its side stand or rear wheel stand.  If propped vertically upright on its wheels it was just about OK with regards spillage but required the sump oil returning to the tank before starting.  I refurbished the oil pump when I built the bike from a pile of bits; the pump had a nice feel to it in accordance with the John Hudson single finger spanner turning test, lots of slurpy noises and pumps well - it just wet sumped too much !  I decided therefore to bite the bullet and purchase an AN Singles pump for a little over £200.

 There was a thread on this forum 3 years ago about AN Oil Pumps ( Not wishing to rehash the whole saga, I take the liberty of pasting below the opening paragraphs of the above thread which seem factual and detailed:

 New A.N.Oil Pumps VERDICT

Posted by les_howard at May 05. 2017

 Fed up with excessive wet sumping and after reading recommendations on the Forum that they are so good, I decided to splash out and buy a new “Andover Norton” oil pump. I chose to buy it from RGM as they are priced the same and I needed other parts from them at the same time. Well the first one had to be sent back as it was initially impossible to turn and when I did get it turning it had a single tight spot remaining....not good methinks so sent it back. It was duly replaced with another one and this time it turned easily and to my mind possibly too easy!... On my old pump's removal, I was struck on how good this self refurbed pump actually was and doing a finger block test on the output it actually seemed to pump harder than the new one. Then I did a static drain-through test and low and behold I could see oil beginning to drain out of the feed nozzle in just a few seconds. Oh dear, I thought, I was hoping for an improvement here!

Now cut to the chase. How does it perform? Well I reckon the scavenge side does work that much better with a very high flow rate and instant priming but sadly the drain through is definitely no better. Now using fresh 40 SAE straight oil this time instead of my 20W-50 oil I was hoping for a really big improvement but sadly and annoyingly I seem to have wasted my money. I would go on to say I would have had a better improvement by leaving in the old pump and switching to the thicker oil.

 I have to say that my findings were exactly as stated above by Les Howard as far as my old pump and its new Andover Norton replacement were concerned.  The loose feel on turning the new pump did not bode well with regards drain-through.  Using John Hudson's 5" spanner test one could almost flick the rotation half a revolution with a small ring spanner attached. Incidentally, the AN nut/threads are 9/16" AF - UNF, not Whit - Cycle, as they are Commandoised.  Upon installation with timing cover off and using 40 SAE oil to check drain through, it was probably no more than a minute before a steady trickle of oil appeared through the feed nipple.  No improvement there ! 

 I would have accepted living with this had it not been for the fitting problems I then experienced in relation to the fit within a 16H crankcase and timing cover which I feel need further examination as in my opinion the AN Singles Oil Pump was not suitable as purchased for installation in single cylinder engines.

 At the 2017 NOC "In-Cider" Rally in Somerset, whilst on display in front of Wells Cathedral I was in conversation with a WD16H owner and the subject of wet sumping and oil pumps came up.  He said he had bought a AN Singles Pump when building his engine but found that the pump mounting studs in the crankcase did not quite match the hole spacing in the pump body.  He said he took both crankcase and pump to Andover to demonstrate this incompatibility and the pump body was re-machined to allow it to fit.

 Being aware of this, and assuming it might have been a one-off problem, or one surely that had now been sorted, I took my old pump with me when going to purchase the replacement. A couple of long 5/16" bolts through the old pump holes seemed to match those on the replacement well enough, so I went ahead with the purchase.

 Upon installing my new pump on the studs in my 16H crankcase it quickly became apparent that all was not well.  It slid on for an inch or so but then started to bind on the studs.  The gear and worm drive were loose enough but gentle tapping was required on the pump body to expose enough thread to allow the nuts to be put on.  As I tightened the nuts I had the sinking feeling that I had past the point of no return as the pump body was definitely getting tighter on the studs.  I fastened the nuts fully but couldn't be sure if I had a proper fit on the faceplate.  I pressed on with the oil check mentioned above and as removal of the pump now didn't seem an easy option, I tried to fit the timing cover.  I had already realised that the diameter of the AN fibre sealing washer was too big for the recess in the 16H timing cover and had turned this down by 0.025" to make it fit.

 With a coating of ThreeBond sealant to the mating surfaces I tightened the screws fixing the timing cover only to become aware of oil dripping from the base.  Peering from below it was obviously there was an obstruction inside as there was a gap of about 1/32" around the lower part of the cover.  Removal and inspection showed a gauge on the inside of the timing cover caused by the rear of the two pump retaining nuts, the gauge mark was removed and the area relieved with a Dremel sander.  I thinned that nut to reduce protrusion and allow the flat of the nut to be adjacent to the cast tunnel inside the cover which it had been fouling (Fig.1 attached). The pump installation at this stage is shown in Fig.2, the top of the reduced left hand nut is just about flush with the stud top whilst the right hand one is still a thread or more short.  I realised then that the height of the pump body had to be greater than that on the original Norton pumps.

 The tapered wooden dowel in the feed nipple is to stop oil flow whilst the cover is off – so much for drain through !

An attempt to refit the cover still proved futile as it seemed that the pump body was too tall for the space available and the top-hat / bleed nipple was fouling the outer case.  It was also noticeable that this AN fitting was of the large flange type as fitted to Twin and Commando pumps whereas all Norton Single pumps have a significantly smaller flange.

 There was no option but to try to remove the pump and measure things.  Unfortunately, the pump was now too tight on the studs to allow it to be withdrawn.  I had to grind a slot in the end of one stud to take a large square shank screwdriver fitted with a spanner.  This just succeeded in turning the stud and unscrewing it through the pump body releasing the pressure to allow easy removal of the pump off the remaining stud.

 The following measurements were made:

1.       The hole spacing in the AN pump was +0.011" greater than the original.

2.       The hole diameters in the AN pump were -0.002" less than the original.

3.       The body height of the AN pump was +0.030" more than the original, Fig. 3  clearly shows the difference.

4.       The Top-Hat / Feed Nipple is +0.042" higher than the original (Fig. 4) :

5.       The feed nipple flange diameter is a whole quarter inch greater than the original and of greater thickness (Fig. 5).  This means it interferes with the cast rim of the hollow for the sealing washer instead of sitting inside it and compressing the washer. This seems the most bizarre aspect of all as even the most cursory comparison with an original pump must realise that if for three decades Nortons fitted a significantly smaller flanged nipple to their Singles pump it was probably for a very good reason.

It would not take much ingenuity to rectify these problems. Reaming the mounting holes to allow greater tolerance, machining the outer body flats to allow the nuts to seat better, fitting a smaller feed nipple or reducing the present one, about an hour’s work, but these would obviously invalidate any warranty on a £200 item.

I returned my AN Singles pumps for refund together with the above findings and photos.  These received neither acknowledgement nor comment. I had to phone subsequently to affect the refund.

All a somewhat time-wasting and frustrating experience, especially when I believe some of the short comings might already have been known about. Nor does it do many favours for a well-respected organisation who's quality control and service to Norton owners is normally second to none.

All this was three years ago, perhaps modifications have now been made to sort the issue.  Possibly Herr Seifert’s NOC representative might confirm or otherwise, the AN Oil Pump being in fact his “part of ship”.

With regards my WD’s wet sumping, I gathered a couple of used ones and some bits at Kempton to swap around parts and refurbish and achieved a quite acceptable result at a fraction the cost of a AN new one.



Pete McDermott

Hi Pete,


Having comprehensively read through your experiences,I can honestly say that my friend will be indebted,as,whilst he is an extremely able and competent engineer (capable of overcoming most hurdles) I doubt that he - like yourself - would be too chuffed to purchase a part that,by the nature of today's advanced technological equipment and production savvy should be of aircraft industry quality,only to discover that it was (possibly..) no better than what Norton were producing in the 30s...

I shall relay all of this to him,and would like to pass on his utmost appreciation in anticipation of his likely opinion as to the benefit of your unfortunate saga!

I realise that all opinions in life differ,and can be at extremes,but,having read the first hand (horse's mouth) experience of this product,that is what is important in ultimately making a decision.


Many thanks for sharing that Pete - it is very much appreciated


I have a load of old oil pumps, any chance of a photo/dimensions and i will see if one of them will fit.



Hi Peter,


Many thanks for your help with this search,as the more options the merrier!

Unfortunately,the (original fitment) oil pump has more or less disintegrated into a substance akin to volcanic ash,so it isn't possible to take a photo for comparison with the pumps that you have,for check of a possible match.

That said..I believe that there is an image on the Norvil site,and,if it were at all possible that you could have a look,that would be very much appreciated.

I have sent an email to Neil Shoosmith regarding a pump on the spares shop site,but as of yet he hasn't got back to me,so any other options for a suitable fix are well received.

Thanks again for your interest! Kind regards - Rob


I do now recall Les's rant, but he was always angry about everything, especially me.

I've spoken with several people who appear to have fitted the pumps without difficulty.

The old zinc alloy bodies are dimensionally unstable if dry-stored and can then fail catastrophically. Could it be that Andover copied an example which had 'blown' ?

I shall withdraw from the discussion as I don't have an Andover pump here to compare and hear-say won't help us get to the bottom of the problem.


Despite researching Roadholder I can't find any info on this %' spanner test for the oil ump. What is it?



The test I use is to put a spanner over the top nut and then place a single finger 4 to 5" away from the nut and on the side of the spanner, if I can't turn the pump with that single finger then the clearances are too tight. You can disassemble the pump and regain some clearance by gently rubbing the sides of the gears down or mount the pump in a lathe on the nut and then drive the pump at low revs and feed it oil, 2 to 3 mins and it will loosen up enough to pass the finger test.


Thanks John. I figured it was that but needed confirmation.




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