I replaced my self aligning bearings with a roller on the timing side and a roller and ball bearing on the drive side. The surface area on the self aligning bearings is quite small and I wouldn't bother with them. I bought them from Russell's.

email (option): horror@blueyonder.co.uk

How critical is it to use C3 tolerance?

Rob

email (option): robmiller11(a)yahoo.co.uk

On a personal basis, I have found this thread enormously interesting and helpful - thanks Ian plus all who have replied !

My own 16H runs on non self-aligning bearings that originally came from Draganfly.............not sure of the make but no issues since whatsoever, no play, no vibration (other than the normal), a big mileage since and I thrash this thing.....

Interestingly though, and to add to the thread, I recently stripped-down my spare 16H engine and this was fitted with the self-aligning bearings as discussed above......they were rather worn, one disintegrated on removal, but the big-end assembly in the engine remains sound and within wear limits....this engine has stampings indicating overhaul at some point by a Middle-Eastern ("E" class) workshop..............I too, am debating what to fit when I get round to rebuilding this unit, but if my up and running one is anything to go by I may simply opt for standard non-self-aligning bearings if the current performance over the last 15 years is anything to go by.........

Thanks again though, for all the useful contributions on this thread......

['How critical is it to use C3 tolerance?..']

'C3' fit refers to the internal clearance of the bearing..Bore, O.D and width are the same as a 'standard' bearing...

The purpose of the larger internal clearance is to take account of the relatively high running temperature and the amount of 'crush' on the bearing resulting from the interference fit when it is fitted to the crankcase..

However, the extra tolerance can be measured in microns so is relatively small...

I believe it is highly likely that many cases have lost some of this fit over the years through repeated and sometimes incorrect fitting and removal of bearings...

Certainly I have used non C3 fit bearings many times in BSA engines without noticeable problems...

Generally I'll use a C3 fit bearing if it is available, though some are now getting hard to find in that fit and in some cases the cost difference is massive...

At the risk of starting off another debate I'll also express my personal opinion (and one confirmed by more than one bearing supplier)that I would only use branded bearings from Japanese, European or American manufacturers for this application...

Of course, in the final analysis that is a choice for the individual...Ian

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

Hi Ian.
Typically internal fit on a standard bearing of this size is between C2 and C3. Which is from 12 to 18 microns. A C3 fit on the same size would be between 15 to 21 microns. So really it's an overlapping tolerance which means C3 just guarentees that you get the upper limit of the clearance for the reasons that you so elequantly stated.

It would be good practice these days to look for C3 but not essential.
I look forward to the list of required bearings in due course, I will certainly help as I can.
Darren.

email (option): Dwrudd at lineone dot net

Hi Darren...Thanks for the extra detail regarding fits...Ian

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

May have already been said, but;

The self-aligning bearings are used in the early 1932/3 TWO main-bearing ES2/16H engines (one each side of the crank) and are expensive and difficult to find - there may be a spherical roller equivalent out there?
The later three bearing engines are not self aligning.

I'm not certain which crankcases the WD engine normally use, but i recently converted a set of two bearing WD marked cases for use on my 1932 ES2 ....?

In all cases C3 or C4 fit are specified, these have increase clearance.

As for using a roller bearing in the drive side, for the mileage we do you can substitute a ball bearing - i ran a (fast)short-stroke ES2 for 3 years without any bottom end problems with balls all round.





As for rigidity - the crank should be rigid - not the crankcases attempting to hold the crank rigid - there are endless cases where the crank was not allowed to move (bend) as it wants - the classic being the Norton Commando combat engine and its 'superblend' mains (also reduce triumph crank from breakage).

One reason why many racing engines simply have a pair of adequately sized mains - without a third 'outrigger' bearing.

(its easy to get & keep two bearings in line, less easy to get three....)

Totally agree NigP, this thread is now so long and confusing it probably defeats it,s initial purpose. To clarify to the best of my knowledge of WD 16Hs which goes back to '76 the mains consist of three identical ball bearings 1" X 2 1/4" X 5/8" (Hoffman) with a small spacer between the two on the drive side. ie no rollers.

The crank and cases are exactly the same as a post war ES2 which use a roller on the timing side and a roller and ball on the drive side. They weren't worried about flexing cranks and self aligning bearing on the OHV engine which puts out more power, so why worry about it on the 16H? The rollers and ball are easy to get and probably cost less than the self aligning bearings. I can't see why anyone would want to use them. I just phoned Russell's and asked for a set, and put them in. It's not that complicated

email (option): horror@blueyonder.co.uk

You're right , you can probably fit ball or roller bearings in any combination you like on timing or drive sides with no problems. I was just mentioning the correct arrangement for a WD 16H as some people seem to like to have everything spot on as period. The bearings I mentioned, I also believe they are RLS8 single row balls, ie not self aligning.
BTW you should get 50,000 miles out of a set of mains so I wouldn't worry about it.

I agree you can probably get away with lots of different components on any old vehicle rebuild and its up to the owner to fit anything they want, but its another matter altogether advising someone else to do it, and this forum could be here in years to come offering bad advise, so I think we need to stick to the facts.

The engine on the Military 16H is basically a 1935 design which was designed to use 3 ball races.

The Military Big4 has a later generation engine more like a late 1930s 16H but with a very long stroke, it probably does produce more torque and was designed to have two rollers and one ball race and it may well need it.

The reasons for using different types of bearing are many and varied, as are the opinions on the subject, just try googling Norton Commando Superblend.

I had hoped that this thread would offer an opportunity to buy the correct bearings directly and more cheaply than through a motorcycle dealer but alas no.

Rob

email (option): robmiller11(a)yahoo.co.uk

You've missread my post. I believe the correct bearings ie OEM for a WD 16H (which is what the OP was asking about), are
3 off 1" X 2 1/4" X 5/8" RLS8 ball bearings (non self aligning single row balls) I would not advise anyone to fit anything else. These are the cheapest of all the others discussed on this post and are readily available from most bearing stockists.

Ten mins on Google

Thanks Keith, so you are recommending "Budget" bearings?

Rob

email (option): robmiller11(a)yahoo.co.uk

Well that was the first place I came to when I googled. However Henderson Bearing are a British company and have been trading since 1949. I have no idea where they source their stock from. I'm sure RHP SKF etc make and sell the same size bearings and are also equally available.
Modern bearing quality is a whole new subject but I'm sure a reputable name is a good enough guarantee.

I have found some good quality C3 roller bearings in the correct size for my big 4 mains but they have a lip in one side, is this correct?

And would the lipped sides be towards the flywheels as in the diagram?

Rob

email (option): robmiller11(a)yahoo.co.uk

Yes that's correct Rob, if the lip was the other way round you wouldn't be able to get the crank out the casing without taking the bearing out the crank case. The inner is tight on the crank, not like the ball bearing on the drive side which is a sliding fit.
There are also shims that go behind the inner for adjusting the end float, it's not easy to take the inner on and off to do this and there are also shims that can go under the bearing in the casing.

email (option): horror@blueyonder.co.uk

Thank you Horror, I'm finally getting somewhere.

Rob

email (option): robmiller11(a)yahoo.co.uk

Hi All

If anyone needs any assistance with bearings please do not hesitate to email me off site.
I have been dealing on bearings for over 30 years and have built up a decent knowledge in that time.
there are many 'budget' brands out there which are usually Chinese rubbish but there are also other options which are pretty good too.
Some of the tapered roller wheel bearings are getting a bit scarce and the few stockists who have them charge a ridiculous amount for them so be careful.
I am here to help and advise if needed but email is best as I often don't get on here for a while as it can be hectic at the office sometimes.:-)


Best regards
Darren

email (option): dwrudd at lineone.net