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Rob's WD16H and Big4 Forum

Dutch army, Johan Herman Fuhler, somewhere between 1945 and 1950

Rob's WD16H and Big4 Forum
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WD16H Primary Case Queries ?

I am desperate for a Primary Chain Case for my nearly completed WD16H project, being built from a very incomplete and rusty box of bits. I have a Norton Single chain case, probably post-war ES2, that I hoped might be adapted as the external dimensions looked the same as that on my 1936 16H, but on trying a fit, there the similarity ends. Photo below shows the problem, I expected the external lugs might require some modification but the relative positions of the crankshaft opening, gearbox shaft and footrest hole present a whole new game. Unfortunately a check fit has not been possible until engine and gearbox were in the frame so I have missed 4 or 5 auto jumble visits where I might have found a replacement.

 photo b70722b5-095b-46a2-82bb-1101d977258e_zpsf7op7sqh.jpg

 photo Inner202_zpstizdgwxd.jpg

Rob's downloaded WD Parts List (Contract 294/C/7353) relevant to my frame number shows the Primary Inner Cover as Part 3410, the Outer Cover 3413.
Definition isn't too brilliant on the image in the downloaded copy so I checked my own hard copy of what I believe is a 1936 Parts list but that shows the 16H Inner Cover as 3653, this also being applicable to the B4 and Models 18, 19, 20, 50 & 55. The ES2 has a different Inner (3654) but all models have the same outer cover 3413 as also listed in the WD publication.

 photo 1936X_zpsnkmwq5y2.jpg

The above Inner Cover (3653) looks very different to the WD's 3410. Most noticeably the latter does not seem to have the hole just rear of the crankshaft opening to take the 5/16" bolt that attaches it to the crankcase and the rear chain guard attachment lug is a much different shape. The lack of a 5/16"attachment hole is a real puzzle as how else can it fasten to the crankcase; I thought all Norton engines have this tapped hole. The chronological parts numbering also seems strange, 3653 for 1936, 3410 for 1940/41.

To find the origin of the WD part number and seek a clearer image I went back as far as my hard copy of what I think is a 1934 List which shows the inner cover as 3410, the same as the WD. The 1933 List is identical. The image below clearly shows the lack of the 5/16 crankcase hole. The footrest hole seems lower and smaller and the rear chain guard attachment lug is much higher.

 photo 1934X_zpscch9uvzn.jpg
My queries therefore:

1. If the correct WD Inner Cover doesn't have a 5/16" hole how is the front end held in place ?

2. As all Inner Covers seem to share the same Outer Cover can anyone supply overall dimensions and/or a decent photo of a correct WD16H inner cover just in case the post-war outer that I have might still be compatible ?

3. Why would the illustrated WD/1934/1933 Inner portion (3410) have that extended higher chain mounting lug when the rear chain guards of that era are much different to WD ones?

4. Finally does anyone please know of an available WD16H Primary Case to allow me to get the bike on the road for the first time in at least 40 years ?

Re: WD16H Primary Case Queries ?

All the inner cases have the mounting hole behind the crankshaft, I wouldn't take too much notice of the drawings in the parts book. I'm not sure as all the outers are the same either. I bought an inner and outer off ebay and wanted to use the outer on my 16H as it was in better condition that what was on there. The footrest hole didn't line up, so I think there are more differences than are immediately obvious.

I've just gone through my pictures of my 16H rebuild but unfortunately I haven't got a picture that will help you.

Re: WD16H Primary Case Queries ?

Pete, Don't pay too much attention to Norton's cut and paste parts list illustrations. They often vaguely altered existing pictures with an artist's brush to reflect production changes.

I have a small collection of 1930s parts books and also an inner case here, waiting to fit. I'll take some scans and photos tomorrow.

As Dave Horror says, the WD chaincase certainly has the front mounting position. Some of the parts number changes related to such things as the use of a welded instead of rolled edge etc.

Any post-1935 open cradle frame inner chaincase should fit (although the Model 50 was odd, I believe) - They do turn up.

Re: WD16H Primary Case Queries ?

Hi Pete, Looking at your picture again, I can't actually see much of a problem with your inner case that adjusting the mounting holes won't cure, unless I'm missing something on the small picture. The only thing you're missing are the 2 circular plates that go each side of the gearbox shaft hole. This slides with the shaft when you adjust the primary chain. That should be easy to make. A good way of joining them together is drill 4 small holes through each and weld in the holes, like a spot weld.

Re: WD16H Primary Case Queries ?

Pete, I've followed in your footsteps with the parts books and I'm puzzled too. It certainly seems that the WD16H and Big 4 used the 3410 inner case which appears in the undated book with the blue cover. I've always assumed it was 1933 - 35.

The later green book which refers to 'subsequent to 1936' looks to me to have been applicable for the 1937 model year (i.e. September 1936 onwards production).

The first WD models were delivered earlier in 1936 so may have stuck with the original chaincase. The change of part number may not have been related to dimensions but maybe just to oil sealing arrangements or similar.

I once borrowed a case that had a welded on flange rather than a one-piece pressing. I used it as a model as the cover I had seemed to have lost its pressed depression around the crank boss.

 photo Chaincase inner ccase mount._zpshztv5tgb.jpg

I don't think that the case you have there is from a post-war model as I had an idea that the mounting positions were different for the cradle frames. This looks to me to be for an open diamond frame.

What I don't understand about it is the raised panel around the crankshaft boss which is going to move the case outwards. I can't see how this won't give clearance problems behind the clutch. Your inner would seem to suit an engine with narrower crankcases ?

I'm not sure that I've ever seen a case with a long top rear fixing such as shown in the early parts book. I believe that there is always a front mounting hole present (and the screw and washer are listed in the book). It's simply a poor illustration... maybe from an even earlier book.

The inner below is one that I thought was right for the WD16H and is intended to replace my repaired original, but I won't know until I can compare them.

 photo Chaincase Inner rrev._zpsce09tgtn.jpg

 photo Chaincase Inner_zps895nvmxn.jpg

The outer case ought to be the same as your 1936 civilian model, I believe. This is mine :-

 photo RJP Primary case_zps0h4fxe4g.jpg

Good luck and let me know how you get on. I may be able to source a rough inner case out here in Belgium but there would be the problem of getting it to the UK quickly.

Re: WD16H Primary Case Queries ?

Thanks guys, your input very much appreciated. That photo of my inner case against the bike probably looks better than it is Dave. In reality, with the crankcase hole aligned and the fixing bolt in place, the footrest spindle is a good 1/2" low in the case and the gearbox shaft, set up with a newish 74 link chain, is hard against one end of the case slot. Since my original posting a friend has sent me a photo of the inner case off his 1956 ES2, apart from my missing slider disks this is identical to the one I have.

Rick's astute observation that the pre-war and WD Parts Lists include the 5/16" fixing bolt even if the corresponding image of the inner casing shows no hole to put it through certainly shows that one shouldn't believe all one sees in a Parts List. As regards dates, I also have original copies of both the blue (1933-35 ?) and the green (1936-38 ?) pre-war parts lists, in addition to the dates "subsequent to" referred to on page 2 of each, my copy of the later edition also has a Norton sticker on the inside referring to a 10% price increase after 1st September 1937.

I hadn't got as far as thinking about that raised panel around the crankcase opening screwing up the fit of the clutch basket, but you are spot on Rick, it's a non-starter. The photos of your inner case are especially useful, at least I now know what I need to be looking for and am sure I will find something nearer to home.