Help dating my "probably" ES2

Hello Bernhard,

A photo would help.

The S before the engine number would indicate a war department Big Four side valve single. It would have the bore and stroke (in mm) stamped after the engine number on the left side of the crankcase. This would be 82 x 120.

S4745 was part of Contract C11297 supplied to the British Army between July and September 1941. Most probably this was a sidecar drive outfit but check your frame for the splined driveshaft. (Maybe cut off).

Check the club's technical folder for information or you can get a manual download from wdnorton.nl

Good work Ian, that first 4 on the CC should stand for the model number, ES2 while the frame number is usually on the head stock. Count the fins on the barrel to give an original engine size.

71X 88 is model 50 while 79X 100 is ES2

The big end and mains are all the same.

To me this is a real bitza.

To me also, that carb has to go. Good advise from Ian to also contact Rob in the Netherlands.

Just a start.  ATB.

Your crank case seems to have suffered some surface damage - but the '82' number looks like the case might originally have come from a Model 19.  The 597cc Model 19 had 82x113 stroke from 1933 to 1939 and then again from 1954 to 1955. The plunger frame looks like post war ES2, and is too early for the post war Model 19 which was either rigid (19R) or swing arm (19S).  So it looks like the crankcase left the factory in a different bike.

So the number on the case don't necessarily tell you the engine size.  From the height of the barrel, it doesn't look tall enough for a Model 19.  Maybe you could measure the stroke with a cycle spoke down the plug hole?  It could be a Model 50 (88 stroke).

A  nice ridable classic when you have it sorted.  It's all there, neat and straight and I'm sure will not take a lot of fettling to get thumping again.   

With regard to the Frame Number, apply a  smear of  good old fashion car body polish,  leave it  dry to a white powder then with a flat squeegee take the dust away; the number indents should become apparent.   

 Good  luck with it.

J

The crankcase stampings look to me to correct for a sidecar wheel drive WD Big 4. These tend to have pretty erratic stampings. "Matching" engine and frame numbers were stamped at the time of despatch and this cannot have been easy on a sidecar outfit with left-hand chair.

The letter stampings look OK for a WD Big 4 of this period and it looks as if the remains of the inspector's stamp are also present (probably M223) If you compare yours below with S4495. The two faint "dimples" are markers for the application of the brass spare parts plates sometimes fixed there. 

The basic side-valve casting is the same as the civilian 1938 - 1939 and 1946 - 1947 OHV engines. I believe that it is as simple as boring out the area around the SV tappets to allow the pushrod fitment.

Here is the closest engine number that I have on file.

Hi Bernhard,

   Your bike is an early 1947 ES2. My best guess is that your engine has had the drive-side crankcase half replaced by the WD big 4 part with those numbers. This will fit your engine as the drive-side case was the same for both engines. The timing side case is different on the s.v. so they could not easily be fitted as a pair. All the other major components are as 1947, although the front mudguard has been replaced and also the rear mudguard stays which are too long at the rear. The frame number can be found on the nearside front petrol tank lug and would be B4 13??? or there about. The original crankcase would have the same number as the frame and the 79 x 100 engine size.

FYI.... All the WD 16H engines were the 1937 pattern, but the WD Big 4 engines were the re-designed 1938 version which continued in production until late 1947.

P.S.    Hello Richard Payne, looks like we have had another posting cross-over. Not to worry, you can't have too much info !