Newman cams

Has anyone tried Newman cams? How do they hold up over time? (either chilled cast iron or Nitrided steel). I am wondering if the Newman nitrided steel cams last as long as hardwelded steel cams.

I believe nitriding is only a surface effect which is only a few atoms thick. A better way might be to weld up the lobes with a nickel bearing alloy steel to get more internal hardness and nitride that after heat treating and grinding.

acotrel said:

I believe nitriding is only a surface effect which is only a few atoms thick.

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Google seems to say you made that up.

I have a Newman PW3 in nitrided steel.

I can't say anything about it's longevity, but I did have to fettle the thrust washer to get some end float. When I first bolted the cases together the cam jammed. It may be because my engine is partly Atlas, partly Commando but the thin washers gave far too much end float and the triangle profile one gave no end float.

pommie john said:

I have a Newman PW3 in nitrided steel.

I can't say anything about it's longevity, but I did have to fettle the thrust washer to get some end float. When I first bolted the cases together the cam jammed. It may be because my engine is partly Atlas, partly Commando but the thin washers gave far too much end float and the triangle profile one gave no end float.

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How much time do you have on it? Racing or street?

It's now my street bike and rarely sees over 60MPH ( honest, officer.)

Very few hours on it, and I hope I won't need another strip down for many years

Newman Cams do have a very good reputation with classic racers in the UK.

jseng1 said:

Has anyone tried Newman cams? How do they hold up over time? (either chilled cast iron or Nitrided steel). I am wondering if the Newman nitrided steel cams last as long as hardwelded steel cams.

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Not to diverge slightly, but the stock Norton cams are listed as a steel in the specs in the 850 Workshop Manual ?
What process gave them long life ? (as long as they got it !).

acotrel said:

I believe nitriding is only a surface effect which is only a few atoms thick. .

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When making various items (i work in engineering)which were then nitrided the main reason for using that process was it was cheaper than other forms of hardening and if the part was made of a suitable grade of metal it would distort very little or even not at all. This ment further machining (grinding ) would not be necessary.
How ever the maximum depth of hardness was always said by the company's preforming the process to be 0.5mm to 0.75mm at the very best an the outer surface was the hardest part which get progressively softer so that once that surface has worn further ware occurs rapidly.
So most of the time nitride hardening is used only as a cheap or quick and easy fix.

Pommie John - Do you know of any Norton racers who have time on their nitrided steel Newman cams?

Rohan - Yeah, what was the hardening process on stock cams - can anyone elaborate? The early Commandos also had steel cores and they held up well. Some of the 850 cams were soft.

jseng1 said:

The early Commandos also had steel cores and they held up well. Some of the 850 cams were soft.

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I have a selection of dommie cams, and they are all steel.
No-one can say what that X1 cam was though - the late 50s Daytona type dommie cams ?

It was well reported that some 850 cams had missed the hardening process, usually just one cam lobe (!?).
And others were all good - or they wouldn't have reached considerable mileages.
Don't blame the cams for makers mistooks..

My fathers shop had a can of case-hardening powder.
Heat the item to red heat, poke it into the powder.
Repeat if a deeper harden was needed.
Made things really surface hard, but kept a soft core so was tough and wasn't going to snap.

Something like this.

Rohan said:

jseng1 said:

My fathers shop had a can of case-hardening powder.
Heat the item to red heat, poke it into the powder.
Repeat if a deeper harden was needed.
Made things really surface hard, but kept a soft core so was tough and wasn't going to snap.

Something like this.

Click to expand...

Click to expand...

I remember using that stuff as an apprentice many moons ago. Basically the surface absorbed carbon at red heat and then was quenched to achieve a few thou of hardness.

jseng1 said:

Pommie John - Do you know of any Norton racers who have time on their nitrided steel Newman cams?

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I'm half a world away from the UK racing scene now. seeley920 is still there and still racing. He'd be the one to ask.

Nitride is more than just surface hardness but also puts insides under high compressing tension too. The dipping powder is a hi carbon source similar to dipping into table sugar.

The PW3 cams that Newman produce are in chilled cast iron. They will also make from billet to customers order, either in EN36 or EN40B.

Chilled cast iron posesses inherent self lubricating properties by virtue of the makeup of the material, and has in the past been well regarded as a suitable material for low to medium stressed items such as cams

EN36 is usually case hardened in a cyanide bath, but long shafts are prone to distortion, so a straightening process is usually applied after hardening, but before final grinding of the bearing journals.

EN40B is a nitride hardening steel, and is relatively free from distortion following the hardening process, but bearing journals are still finish ground after hardening, the same as for EN36.

For future use by overlaying with weld and reprofiling (when necessary) EN40B is difficult if not impossible to overlay unless all the outer surface of the profile is ground away, whereas there is no such difficulty at all with EN36.

Both steels may be used with every confidence, but for arduous conditions where flat or radius tappet are used, cams or followers may be DLC treated. Roller followers can run direct on either material without the DLC treatment, but of course are not as yet incorporated into any Commando engine that I am aware of.

My experience with Newman cams is not good, delivery and fitness for purpose being the main issues.

The preferential camshaft material was always chilled cast , but to get the forged blanks manufactured at a sensible cost you have to commit to big number production runs
of forgings then get the profiles ground Which is a very costly procedure for any single vendor

Norton camshafts are not a high turn volume production item so recovering investment would be a very slow process

this is why we see the EN 36 / 40 nitride camshafts these can be manufactured from a solid material often in low batch production at a sensible unit cost

I think AN do use Newman cams as do SRM for BSA stuff

SRM tried the DLC coating on their BSA lifters and it failed. They are going back to stellite pads. Newman cams will cut cams to any specs without hitting you with a setup or master charge and this is almost irresistible to me in my efforts to redesign the PW3 cam with smoother closing ramps to raise the RPM limit before hitting valve bounce. I just have to supply the all the lift numbers at every degree to them. I just need some reliability confirmation about the Nitrided billet lobes before I proceed.

Norton roller cams do exist but there’s a lot of development left to do. See sample images below that were sent to me.





Snotzo - what do you mean by "fitness for purpose" - a PM would be best.

Interesting comments on cast iron vs. steel Norton cams. From an article in the initial issue of Classic Racer in Summer of 1982.



I find it a little confusing. Cast irons in general have much lower elastic modulus than common steels, so I would expect the cast iron cam to be more flexible, not less. Might have something to do with other mechanical properties, like different modulus in tension vs. compression, but I haven't found a good explanation anywhere. I recall reading somewhere else that PW chose a chilled cast iron for the cams, but even that doesn't have as high a elastic modulus as common hardened steels. Anyone here have a good explanation?

Ken

Frankie17 said:

The preferential camshaft material was always chilled cast , but to get the forged blanks manufactured at a sensible cost you have to commit to big number production runs

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Preferential for who/what though ?
Norton cams right back into the early dommies are always steel.
And a very high quality of steel too, as indicated by the solid 'clink' if you clinked them together.

'Forgings' and 'cast iron' in the same sentence doesn't make sense, you don't forge cast iron.
Or are we mixing our subjects here, and steel cams are forged into blanks...

I'd comment that I have snapped a cast iron car cam, under rather arduous conditions admittedly.

The cast iron camshaft is considerably weaker than a steel item of identical dimensions.

By drilling the steel shaft it is possible to make it weaker (less stiff) than the cast iron undrilled version, but to do so the hole size would need to be 16mm or greater. This is the only possibility that would make sense.