" The Camy Norton" ???

I loaned 1/2 dozon vintage bike books to a friend who rides but thinks of a 1980's Japanese two stroke as a "Vintage" bike! Anyway he ask me why they refer to the 1930's to 1950's Nortons as " the Camy Nortons" ??? I have read about them but can't remember why they are called that. Can someone please explain it to me? Thanks.

Manx had an OHC (bevel drive).

I assumed it had something to do with them but isn't more to do with the way the motors felt as in "very camy"?? All of the bikes run the vales off a cam in one way or another.

Norton Internationals were also overhead cam.

There are a lot of advantages to overhead cam: lightened valve train, less reciprocating mass, usually higher valve lift values because of the reduced friction, usually higher RPM values, less wear. They were a lot more expensive to make back in good old days, hence the rarity of overhead cam streetbikes until realatively cheap Japanese bikes with overhead cam engines came on the scene. It's hard for us folks now to imagine just how revolutionary it was back in the 60's to see an overhead cam multi cylinder bike on the showroom floor for less than the cost of other bikes with twice the capacity. In the earlier days, the lack of a reliable mass produced chain tensioner, the lack of high manufacturing tolerances, and good and consistent metallurgy made pushrods the cheaper alternative.

Kevin

As mentioned "cammy" simply refers to the overhead cam bikes of the day. A "cammy" Ariel Square four is any of the early overhead cam Square fours. Later Square fours were not overhead cam. The early cammy Square fours are more valuable because of their age, rarity and the sportiness associated with overhead cam engines. I have a friend who ownsa 52 Ariel square four, below head cam. He can often be heard saying " I would love to own a Cammy Ariel someday!"
In actual fact the later below head cam Ariels were more powerful due to their larger displacement.
So that is about it, when the Brits talk about a cammy Norton, Ariel or Velo they are rferring to the overhead cam models.

Ive heard the term used differently in North America. People here may refer to an engine with a narrow and hig rpm powerband as "Cammy" or "pipey" . The other term that comes to mind for that type of powerband is Peaky, althoug that is often used in reference to high performance two strokes such as the Honda cr500 and all the others who tried to copy the magnificent Maico 490 powerband but never quite got it.

Glen

The press of the day referred to bikes powered by both the Moore and Carroll engines as 'Camshaft Nortons'

'

The Amercian Sportster pre-Peel dragged against was a cammy Harley as it wanted to die off throttle so needed blips and if given smooth throttle such as leaving a light in traffic it just sort a bogged down then suddenly roared, a real nuance. I think this is world wide connotation even with the Nortons, which likely refers to their good response giving great torque rise right now. A narrow peaky power band is the iconic description but some can come on cam sooner for wider thrusting power. I never heard cammy refer to the cam placement, just its profile.

Cammy - different names for different folks. ?

In a lot of parts of the world, that sportster would be referred to as "cammed".

In the teens, the ultra-flash overheadcam oval track racers from Cyclone, Excelsior, Reading Standard and Indian were refeered to as "cammers". You'd probably need a million bucks to find one these days....

In the twenties, the english overheadcam racers from Sunbeam, JAP, Velocette, OK Supreme, Norton etc etc were referred to as "cammy" motors. It was said that sidevalve motors ran out of puff by 4000 rpm, overheadvalve by 5000 rpm and cammy motors by 6000 rpm. Later dohc Norton 350cc motors were supposedly good for 8000 rpm, but only if you had a good engine builder....

Rohan said:

In a lot of parts of the world, that sportster would be referred to as "cammed".
.

Click to expand...

P.S. The 4 common ways to get more performance out of an engine = the 4 C's.

Cammed
cubed
carbed
compressed.

ie hotter cam, more capacity, bigger/better carbs, more compression.

But we diverge from "cammy" - which only applies to the Norton overheadcam (and doubleoverhead cam) engines...

OK this furthered my Norton education - that the OHV models had "cammy" term applied to them for the cam location, instead of the higher rpm power band the rest of the world and era's use the term to describe the response to throttle behavior. not the location or cam drive.

Here's a 500 cc "Cammy" engine for sale.
http://aberdeen.craigslist.co.uk/mcy/2983805692.html

Here's another brands cammy era engine.

The “Cammy” engine gained a reputation for overheating the rear cylinder heads, so in 1936 the engine was completely redesigned, emerging as the 1937 OHV 995 cc model 4G.[1] In 1939 Ariel's patented Anstey-link plunger rear suspension became an option.[4]

I think we are missing something here ?
It was the OHC models (overheadcam) that had the term cammy applied to them.

Overhead valves were overhead valves were ohv, never a cammy...

P.S. Don't confuse square four engine ohc layout with overheating cylinders, the back cylinders are always going to get hot, even the later 1000cc ohv designs suffered from this.
Going to a 4 pipe (exhausts) helped too, in the 1950s, but never entirely solved the problem.

Watercooling would have (a la RG500 design), but thats getting complcated.
At least a V4 only has one crankshaft, and 2 separate cylinder heads.

hobot said:

Here's another brands cammy era engine.

Click to expand...

That's a post-Cammy era Ariel as it is the 4G OHV.


OHC 4F
http://www.theworldofmotorcycles.com/vi ... ariel.html

The Square Four layout marries a pair of 'across frame' OHC parallel-twin cylinder heads (known as the "Cammy") into a single monobloc four-cylinder head, with both crankshafts connected by geared, centrally-located flywheels. The first Square Four was only 500 cc, with chain-driven overhead-camshafts, and the transmission was a four-speed Burman.

Click to expand...

If anyone is interested,....
Here in South Oz we have a privately owned Museum containing mainly Ariel square fours
( estimate.. 30 of ) includeing one Chopper, and early 30's ( i think ) V8 Chevs.
I will get some pics if anyone is interested.
AC.

Would like to see a pic or 2.
Don't go overboard, there weren't that many different models of Squaffers !

And Ariels weren't considered the epitomy of cammy bikes either ? (sorry Ariel owners ), race CS1's and Inters and Sunbeams and Manxman, now your talking. And BSA DOHC and Manx DOHC and then the whole raft of race Rhondines and Gileras and MVs and Guzzis, including the fabulous Guzzi V8.....

And the luxury 1930s Matchless Silver Hawk V4, and AJS supercharged watercooled V4 racer, the picks of the bunch...

Ok I am straightened out on 'cammy' term as the British applied it to various breeds and engine designs. I've seen designations of OHV and OHC and DOHC that each kind, came in mild or hot 'Cammy' camshafts. So still of a confused opinion that 'cammy' referred to the cam profile only and if a new hotter profile also had a new drive and;or placement then 'cammy' ID'd both new features. Part of the reason for the OH installs was better valve control with more aggressive cams, I think.

On first seeing a Square 4 I can't tell ya how mechanically satisfying it was see such a compact dream engine actually produced, still do even more now I've seen them opened and explained.

hobot said:

Ok I am straightened out on 'cammy' term as the British applied it to various breeds and engine designs. I've seen designations of OHV and OHC and DOHC that each kind, came in mild or hot 'Cammy' camshafts. So still of a confused opinion that 'cammy' referred to the cam profile only and if a new hotter profile also had a new drive and;or placement then 'cammy' ID'd both new features. Part of the reason for the OH installs was better valve control with more aggressive cams, I think.

On first seeing a Square 4 I can't tell ya how mechanically satisfying it was see such a compact dream engine actually produced, still do even more now I've seen them opened and explained.

Click to expand...

Just to add to your confusion the Velo factory made a 350 OHC engine at one time and for the pushrod operated valves on their 350/500 Venom called it a high cam :!:

Rohan said:

Would like to see a pic or 2.
Don't go overboard, there weren't that many different models of Squaffers !

And Ariels weren't considered the epitomy of cammy bikes either ? (sorry Ariel owners ), race CS1's and Inters and Sunbeams and Manxman, now your talking. And BSA DOHC and Manx DOHC and then the whole raft of race Rhondines and Gileras and MVs and Guzzis, including the fabulous Guzzi V8.....

And the luxury 1930s Matchless Silver Hawk V4, and AJS supercharged watercooled V4 racer, the picks of the bunch...

Click to expand...

A good friend of mine, Dan Smith, has a Silver Hawk in his garage. He restored it a few years ago.
The AJS V4 was tougher, he had to build that from scratch, took 18 months. Ive ridden it and it is super smooth.
His current project is to recreate the Velo Roarer. The original belongs to Ivan Rhodes. Ivan has supplied Dan with the necessary measurements.
Dans recreation should be running about this time next year.
He builds the moulds, pours the castings, machines the gears, the whole enchilada. Amazing.

Glen

Heres the ajs

http://www.motorcycleclassics.com/class ... plica.aspx

After the AJS he built himself one of those 225,000 gbp seriesA Vincent Rapides, all done in his basement workshop from raw lumps of metal, then a 1912 Acme VTwin and now the Roarer.

Glen

Rohan said:

I think we are missing something here ?
It was the OHC models (overheadcam) that had the term cammy applied to them.

Overhead valves were overhead valves were ohv, never a cammy...

P.S. Don't confuse square four engine ohc layout with overheating cylinders, the back cylinders are always going to get hot, even the later 1000cc ohv designs suffered from this.
Going to a 4 pipe (exhausts) helped too, in the 1950s, but never entirely solved the problem.

Watercooling would have (a la RG500 design), but thats getting complcated.
At least a V4 only has one crankshaft, and 2 separate cylinder heads.

Click to expand...

As the owner of a couple of ohv square 4s I am consistently asked about the rear cylinders overheating. I have to say it is a fallacy. I have regularly ridden in 40 degree C heat (over 100F) without any problems. When I built my MK2 engine I had the cylinder bored to only .0015 clearance on both front and rear cylinders and I have had the head shaved to raise the compression which will of course increase the heat. In the OHV 4s the cylinders were moved further apart and there is an air passage between cylinders that did not exist with the cammys. They still run hot but there is no problem with overheating or ceasing rear cylinders .
The cammy 4s did have a reputation for overheating and ceasing rear cylinders and the fix is to bore the rear cylinders .002 larger. The cammys also had regular magneto failures due to the excess heat from the engine and are best fitted with an electronic ignition mounted well away from the engine. The other problem with the cammy is that there are only 8 headbolts to hold the head down on 4 cylinders so blown headgaskets were not uncommon.
The original cammy did however feature many innovations. Chain driven overhead cam, roller bearing big ends and horizontally split crankcases, and with the original design and prototype, an integral gearbox. Both cranks were coupled by helical cut gears cut on the central flywheel with the gearbox being driven from the rear flywheel. The manufacturing costs proved too high with the prototype so a separate gearbox was used when production commenced. Interestingly the500cc single cylinder Red Hunter of the day put out 5 HP more than the 500cc cammy. The cammy 4 had a valve timing of inlet opens 10btdc closes 50abdc exhaust opens 55bbdc closes 15atdc which is very mild by anyones standard.
Ando.

Its a tailwind on a hot day that does them in ? At a club meeting, someone was telling of a recentish rally in high temps, where the ohv Sq4 1000 in attendance warped its cylinder head, and limped to the next towns bike shop. Apparently this was a well known foible back then - the meeting errupted into laughter when someone quoted the Sq4 advertising slogan from back then "Everyone will own a Sq4", and as a chorus, all the old timers chanted back "ONCE !".

Undeterred, the rallyee bought a nicely restored XS1 on the showroom floor, and finished the rally (6 day event)....

When most cammy bikes came out in the 1920s, performance was underwhelming. It took quite a while to figure out the valve timing needed s-t-r-e-t-c-h-i-n-g out to get the overlap they needed for the go they were capable of. Ariels didn't have a comp cammy, may not have found this path ? Or, the cooling wasn't up to it, and they knew it ??

P.S. the gas flow path design from a single carb into a sq4 head is awful, from a distribution viewpoint, so good performance is not going to be as simple as finding a nice tuned length and entry angle.... Nice touring bikes though, and handsome as to look at...