I have a new-old-stock Norton 16H cylinder barrel here that I hope to fit to my spare engine...............

The barrel is the correct WD-type...........but currently measures approximately 82mm without any liner..........

If I fit a cylinder liner, I assume this will take the bore down to 79mm ?

And I assume looking at the NOS item that Norton's were fitted with a cylinder liner as standard ? Any advice appreciated here.........

The Big 4 had a bore of 82mm...Could this be a pre war barrel for that engine?...(I know the wartime ones differed from the 16H with enclosed valves etc.)...

A 1.5mm liner wall thickness after boring to the 79mm finished bore size would, however, be quite OK...
You will need to have a liner with a bore below that size to allow for finishing after fitting...(78mm or less ideally)...

If not readily available you will probably be able to get a liner from Westwood Liners if you can supply the essential dimensions...Ian

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

Why an NOS cylinder would be bored out at the factory to receive a liner is beyond me. Norton cylinders came bored standard size with no liner. Liners were only installed once the cylinder was bored out to it's maximum piston size in order to return to the initial standard.

I have an NOS liner. O/S measurement is 82mm, wall thickness is a hair under 2 mm. Inside diameter is 78mm, allowing a mm or so for final boring, honing.

The manual states not to re bore the liner to oversized pistons, rather to remover the liner and replace with a new one, therefore maintaining standard size. Interestingly enough, I have a lined cylinder that had a 60 thou over piston installed, the walls are very thin, goes to show, the manual wasn't always followed as the Gospel.

It would seem nonsensical for replacement cylinders to be bored at the factory to accept a liner which would then bring the bore to standard size.

Nonsensical...unless the "NOS" is actually a recycled/reconditioned secondhand item, bored out to receive its liner? It would make sense to reuse all those cast off barrels returned from sevice depots??

['It would seem nonsensical for replacement cylinders to be bored at the factory to accept a liner which would then bring the bore to standard size.']...

BSA did exactly that when building M20s and for replacement parts, using a lower quality barrel casting with a liner fitted as standard...
However, the liner was also fitted and sized at the factory so the barrel was ready to use in the latter case...

Of course that doesn't mean Norton followed the same practice...Ian

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

I have a genuine NOS WD 16H cylinder barrel and can confirm that they do not have liners fitted. I used to have a few. bought as spares ex government surplus but am down to my last one now.


If you ever have to fit a liner don't forget you will have to drill a new oil feed hole to lubricate the rear piston wall.

Factory-fitting a liner has some logic but clearly wasn't normal for the WD16H. Would they have done it with cylinders that were out of tolerance in some way ? Possibly although I suspect that they'd have gone back in the smelter. If they were bored for a liner then as Ian says this would only have made sense if the liner was factory-fitted.

If not factory-fitted, there would have to have been a part number for a cylinder suitable for lining.

If this is a 16H (100mm stroke) cylinder then it has either been overbored by someone ready to use a Big 4 piston (which can be done) or it is a factory production fault. I wouldn't rule this out - I've seen WD16H cases with a 'W' number stamped '82x120' rather than '79x100'

Is it definitely NOS and not a rebored barrel that was incorrectly labelled during a 1950s ordnance stock control and re-packaging exercise ?

email (option): ronpier@talk21.com

No, Ron ! You passed on the short-stroke ex-works racing engine that they put together for the 1940 sidecar TT !

['If this is a 16H (100mm stroke) cylinder then it has either been over bored by someone ready to use a Big 4 piston (which can be done)...']

If that's the case I'd do it...That would make 528cc and these old side valves benefit from all the help they can get.. ...Ian

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

Couldn't it just be a 1935 big4 barrel?

Rob

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

I really appreciate all the above advice and opinions from colleagues and friends who know more about this stuff than me.........

I did initially think a pre-1938 Big 4 barrel but am unsure, apart from the obvious bore size, if these are the same as the 16H or different in some respect (eg - taller ?)........anyone know if these pre-38 barrels differ ?

The barrel, although rusty, is in otherwise undamaged condition with really good fins, etc. I guess it COULD possibly be a reconditioned, bored-out 16H item but not (yet) fitted with a liner............

Thanks anyway chaps.......

Pre-'38 Big 4 barrels are, as per the later (and WD) type, about an inch taller than 16H cylinders (the extra 20mm stroke). If this is a Big 4 item then the difference should be obvious.

Later WD16H barrels have a thicker base flange. Pre-war military and civilian were stamped with the engine number (although spare parts wouldn't have been). I've seen quite a lot marked 79x100 as well, and sometimes a stamped oversize.

Any chance of a photo of the drive side base flange, Steve ?

['Pre-'38 Big 4 barrels are, as per the later (and WD) type, about an inch taller than 16H cylinders (the extra 20mm stroke)....']

The barrel would only need to be 10mm (.400" approx.) taller due to a 20mm longer stroke...

Is there a rod and/or piston difference as well?..Ian

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

Thanks Ian and Rik for this info........I'll have another look at the barrel tomorrow and get an image or two....

Also Steve, the liners had a lip at the top, this would require the cylinder top flange to have a groove turned into it at the rim to accommodate the liner lip. I would assume that if for any reason this was an NOS cylinder intended for liner fitment , it would have had this lip turned into it at the factory?

Forgot to mention that the barrel is 16cm from the base (not including the spigot) to the top where the head gasket would fit.........on the left side 13 fins.......I haven't got my 16H here at the moment to compare...........

Would someone be able to tell me how many inches tall a Norton 16h and or 18/es2 motor is from the bottom of the crankcase to the top of the head / rockerbox? Thanks Anton

email (option): antoneastman@gmail.com

Samuel stated that the liners had a lip at the top.

I am fairly cetain that that is not correct/universal.
I have two liners and neither has any sort of lip at the top.
I also have several cylinders with liner and show the liner thickness to be identical at top and bottom.
My conclusion would be that a lipped liner was not intended for the military WD16H.
There is also no mention of that in the M&I manuals.
Drilling the oil hole is!

Cheers,

Rob

email (option): wd16h@telfort.nl

Whereas the M20 did use a 'stepped' liner..Ian

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

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

['It will fit in the frame if that's what you want to know, but you won't get the rockerbox off..']

I don't know anything in detail about the Model 18 engine but the 'Big Fin' Gold Star has the same problem...The head and rocker box have to come off together before the rocker box can be removed from the head...

However, if the rocker box studs are replaced with bolts it is possible to get it off without removing the head (which is a right pain)...Might that work for the Norton?...Ian

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

In the proper frame you can take the engine apart. I guessed the measurements were to see if it goes in a WD16H frame? It's tight, the bolts come out but it won't lift over the valve springs.

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

Thank you very much guys for the measurements. This should help me.

email (option): antoneastman@gmail.com

So what was the reason for the question, Anton ? With a little more information, you could probably have received a much more detailed answer. There aren't many things that haven't been tried in the world of old motorcycles ! :grinning:

Rob, perhaps different liners existed? This one is still in cosmoline and was wrapped in brown paper with Norton designation. The paper is gone.

email (option): cormiersam@hotmail.com

Hello Samuel,

According to a Hepolite catalogue, all Norton models in the thirties (WD16H upto 1947) had plain liners.

Flanged liners are post war items for e.g. Dominators.

Cheers,

Rob

email (option): wd16h@telfort.nl