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Norton 16H Main Bearings

At a bit of a loose end today whilst awaiting parts to get another James ML finished for a friend, I pulled apart a spare WD 16H engine I had lying under the bench. I've had the thing for years and kept it as a spare for my 16H. Scraping off the grime and giving it a thorough clean down it bears stampings suggesting that at some point it was overhauled/rebuilt by an "E" Class Workshop somewhere in the Middle East.....

Stripping it down, internally it appears in very good condition. But on inspecting the three main engine bearings which are RL8's, I was rather surprised to see that they were the double-row self-aligning ball type. Previously, I've only seen the non-aligning single ball type. The bearings remain in good condition but I'll probably replace them anyway prior to rebuilding the engine. They've probably been in there since the last workshop overhaul many years ago......

The question I have is what are anyone's thoughts and experience in using self-aligning bearings for the engine as opposed to the standard type ? Thanks, Steve

Re: Norton 16H Main Bearings

I can't really see that an accurately machined, matched pair of crank cases would need self aligning bearings...If the main bearing housings were machined out of line to each other and that was Nortons answer to it I definitely won't be buying a Norton any time soon!!:laughing:...

I wouldn't have thought that would be the case though (surely) and it's probably just a case of fitting one thing when the other wasn't available...Of course, it might have been done by an enthusiastic Arab some time after demob...I've seen every form of lash up on machines from the Middle East, India, Pakistan, The Phillipines etc.:hammer_and_pick: Ian

email (option): ian@wright52.plus.com

Re: Norton 16H Main Bearings

Hello Steve,

I have found the double row ball bearings in most of the 16H engines I have(6).
Technically these bearings are intended to a allow off axis rotation (self aligning) which would be useful when shafts are bending.
Apparently early Norton engines only had two crankshaft bearings (I have been told but not checked).
Maybe Norton also did not fully believe in their ability to have both bearings lined up in the crankcase halves.
Because the WD16H engine has two bearings on the drive side the tendency of the crankshaft to flex is much reduced and for that reason I think it is not necessary to use a double row bearing.
Its possibly the Norton conservatism that made them use it on these engines.
Single row ball bearings also allow for a certain amount of mis-alignment (but less than the double row), and this is sufficient for this application.
Double row bearings do also allow for a higher loading but as these engines can hardly be stated as high powered, single row bearings are sufficient. I use single row ball bearings for the last 35 years and never had a problem.
There is a significant price difference!

Cheers,

Rob

www.wdnorton.nl


email (option): wd16h@telfort.nl

Re: Norton 16H Main Bearings

Thanks Rob and Ian for the useful replies....

I've had a look at the bearings fitted to this engine and they are "R & M" (Ransome and Marples) manufacture. I very much doubt that this engine was "buggered about" with after disposal, particularly as the engine cylinder still had a small brass workshop tag fitted beneath one of the base nuts indicating the bore measurement after overhaul. Had the engine been subsequently stripped down following disposal this would have been one of the first things thrown away by a new owner....

The Middle Eastern Base and Auxiliary workshops (the latter indicated by a "E" rather than "B") were run on the same lines as UK workshops, employing a mixture of Military and Civilian personnel, and under REME supervision (from 1942) the quality of work carried out had to comply with particular standards and subject to inspection.....

Whilst this engine has seen some service since workshop overhaul, it doesn't look like it was stripped down following that....

Re: Norton 16H Main Bearings

Sturmey had 2 of them standard in some of their 3 speed gearboxes:

20200416-134201

Re: Norton 16H Main Bearings

Norton went on to use self aligning bearings again in the '70s, on the Commando, after a spate of main bearing and crankshaft troubles. I'm sure we all know this story, the solution was the much vaunted "Superblend" bearing, a single row roller with the rollers barrel shaped to allow the crank to flex, may have seemed to be a bodge but it did the trick. Creative engineering.
Earlier Nortons, 1920s, did only use 2 mains and I've come across all sorts of combinations of ball, roller, and self aligning types. They all seem to work as long as the crank is correctly located sideways. Also found all types in later engines with 3 mains and these seem ok too. May be a case of what was available when the engine was built.

Tony

Re: Norton 16H Main Bearings

Actually, we've discussed these bearings before...It seems likely that the self-aligning Hoffmans were a WD requirement bu there is nothing in the MEE reports to indicate failures of others.

Probably a purchasing officer at the War Office had been included in the party for a weekend's shooting on the MD of Hoffman's estate...

http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1127262&cmd=show

Re: Norton 16H Main Bearings

I'm guessing there is no surviving standards book for he 16H?...At least they didn't have the bizarre and seemingly unnecessary Velocette pre loaded bearings arrangement...

It always amazes me how manufacturers stick with expensive and complicated solutions when simpler ones are proven to be successful in faster and more powerful bikes...Ian

email (option): ian@wright52.plus.com

Re: Norton 16H Main Bearings

Sadly, when AMC moved production to Woolwich, they seem to have discarded everything that wasn't applicable to then-current production (the early 1960s).

The second drive side bearing had arrived for 1934 but the part number remained unchanged, simply one extra. The wartime workshop manual states "Engine Bearings. Ball (3). 1" x 2-1/4" x5/8"

The bearings seem to have arrived with the 1932 Edgar Franks redesign. It would seem that the 1932-1934 engines were fitted with two of these bearings and thereafter, three. For pre-1938 500cc and 600cc OHV engines this was part no. 9033. WD for 1937 used the same part number but added 'Hoffmann'. The civilian parts list for 1938 includes a mainshaft roller bearing (8858). WD16H continued to specify simply the 9033.

Nowhere though does it actually mention 'self-aligning or give a usable bearing code.

Re: Norton 16H Main Bearings

Many thanks for the additional replies chaps - very interesting....

"I'm guessing there is no surviving standards book for the 16H?" mentions Ian. Just to expand on this a little, the "Standards Book" is an A4 comprehensive publication compiled post-war by the War Office specifically detailing the technical measurements and wear limits for all components of a particular motorcycle, and was intended as a definitive guide for military workshop examiners/inspectors for machines undergoing overhaul.....

Around 10 years ago now I was fortunate enough to acquire two original copies of these "standards books" for the G3L and the M20, limited copies of which I made and made available to Forum members. They are absolutely invaluable to anyone overhauling or restoring a Matchless or BSA simply because they provide the most detailed information available on critical wear measurements and according serviceability....

I'm not at all certain whether or not these publications were made covering other makes and types of WD motorcycle. Whilst these were compiled during the 1950's and smaller quantities of some other wartime machines remaining in service throughout that decade, such as Norton 16H's, Ariel W/NG's, Matchless G3's, etc, it would seem that during that period the military had chosen to retain both the G3L and M20 in limited quantities as the standard motorcycles for the services, hence the two publications I found. Others may exist, but I simply don't know....

Re: Norton 16H Main Bearings

Here's my original copy of the M20 standards book...A little different to Steves...Ian

email (option): ian@wright52.plus.com

Re: Norton 16H Main Bearings

What I am still wondering about, there must have been infromation like in the postwar standards books even prior or during the war.
RASC and REME stations did apparently straighten and repair frames so they should have some reference.
Even if they received the jigs to repair frames there must have been people making those jigs.
As shown in O&M they were fairly sturdy and fork and frame work was not uncommon.
I would still very much like to have the frame measurements and wear limits for the WD16H but they have been elusive for a long time.
I am quite envious on the Matchless and M20 guides. Very comprehensive.

If anybody has frame measurements for the Norton, please contact me :smiley:

Cheers,

Rob

www.wdnorton.nl

email (option): wd16h@telfort.nl

Re: Norton 16H Main Bearings

The Inspectorate of Fighting Vehicles who produced the standards book I have was located in Yester Road, Chislehurst, Kent...No sign of anything on Google Maps etc...The area seems to have been redeveloped as a 'leafy suburb'....Ian

email (option): ian@wright52.plus.com

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