Cam and follower tests.

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o0norton0o said:
The stock followers have their stellite pads attached by oven brazing. Sadly, some of these pads will eventually delaminate from the body of the follower and can do some serious damage to the bottom end. I had a follower lose it's pad while my bike was idling in the driveway last year. I heard the noise start, shut the bike off then went through the long process of pulling the top end apart to find the follower's pad detached, sitting on top of it's cam lobe. No damage! I got lucky as hell.

A norton friend of mine, just this previous weekend had one of his intake valves drop it's captured pushrod. All of a sudden he has a great amount of play in that valve train linkage. (I suspect he lost the stellite pad on his follower...) It happens often enough to be a flaw. He rode his bike home on one cylinder. I'd hate to see what his cam looks like now... (probably like Jim's cam looked)
Click to expand...

I'm the Norton friend and it appears this problem with Commando cam followers is quite prevalent. I recently attended the INOA Tall Timber Rally and was bragging about how my 1975 MkIII had over 50K original miles with no engine work. Ha ha! 300 miles later the stellite came off the intake follower and now I'm looking at an engine rebuild. So about the comment that, "Norton cam and followers, within certain limits, were fairly successful for 40 years." 43 years in my case, but it's a ticking time bomb! I'm a little mad and like Jim don't want to risk the same failure.

I'm looking at cam and followers from JS Motorsports. This looks like a good solution. Has anyone had long term experience with this?
https://jsmotorsport.com/product/complete-cam-kit/
 
Obviously these types of issues (soft cams, iffy followers, etc. ) are a blessing in disguise. They force us to rebuild the engines on a frequent basis. :confused:
 
So much for vetting original followers by sourcing higher mileage ones.

The evidence at this point makes me want to buy new followers and have them tested for hardness. Should any new followers fail the test will they be accepted by retailers as defective?
 
comnoz said:
Yeah, I was working for GMTC at the time. Running around to the dealers telling them to use MOA with every oil change and mentioning that only cars who had dealership service records showing that were likely to be covered under the extended warranty.
Click to expand...
MOA ... ???
 
Bruce W said:
I'm the Norton friend and it appears this problem with Commando cam followers is quite prevalent. I recently attended the INOA Tall Timber Rally and was bragging about how my 1975 MkIII had over 50K original miles with no engine work. Ha ha! 300 miles later the stellite came off the intake follower and now I'm looking at an engine rebuild. So about the comment that, "Norton cam and followers, within certain limits, were fairly successful for 40 years." 43 years in my case, but it's a ticking time bomb! I'm a little mad and like Jim don't want to risk the same failure.

I'm looking at cam and followers from JS Motorsports. This looks like a good solution. Has anyone had long term experience with this?
https://jsmotorsport.com/product/complete-cam-kit/
Click to expand...

They can have the same problem. The only time I have had a Stellite pad come loose was using a BSA follower....
 
comnoz said:
They can have the same problem. The only time I have had a Stellite pad come loose was using a BSA follower....
Click to expand...

As far as I know you are the only Norton rider this has happened to.

These BSA cam followers never fail because they are hard face welded directly on to the steel (not brazed pads). Nortons owners who are using them now can rest assured.

Cam and follower tests.


There was a lot of demand for them and SRM sold out. I bought as many as I could and offered to buy 100 more but they told me it would take 20,000 english pounds to fire them back up. So someone with deep pockets needs to step up. They would be cheaper to make than the Norton cam followers and the development/testing has already been done years ago.

I was told that Stellite 6 was used. But other compatible hard welds would work.

Here's some data on Stellite 6
http://exocor.com/downloads/product-datasheets/Stellite-6-Datasheet.pdf
 
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Jim, the SRM followers were indeed hard welded.

However, stock BSA ones had stelite pads, same as Triumphs.

Stock ones have been known to suffer pads coming off. But, as with Norton’s, it’s a rare occurance.
 
When hard facing weld is applied it is important that the parent metal does not mix with the hard facing or the result is reduced and possibly uneven hardness of the hardfacing.

Stellite hardfacing is generally applied with an oxy torch and in order to stop the metals mixing the parent metal surface is brought to a sweaty state rather than a molten state, and the hardfacing is melted over the surface. So there is a fine line between having the hardfacing contaminated with parent metal due to melting of the parent metal, or the hardfacing not being properly welded to the parent metal as the parent metal surface was not sweating enough. I have seen several failures where stellite hard weld on a cam has come off in a slab because the parent metal was not hot enough to weld to the stellite hardfacing.

I have also seen stellite hard facing wear rapidly where it was applied with a tig and the parent metal contaminated the hardfacing.

It is possible that the hardfacing pads were brazed to the Norton followers to give a more consistent result than could be achieved by hardface welding by less skilled workers.

ando
 
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ando said:
When hard facing weld is applied it is important that the parent metal does not mix with the hard facing or the result is reduced and possibly uneven hardness of the hardfacing.

Stellite hardfacing is generally applied with an oxy torch and in order to stop the metals mixing the parent metal surface is brought to a sweaty state rather than a molten state, and the hardfacing is melted over the surface. So there is a fine line between having the hardfacing contaminated with parent metal due to melting of the parent metal, or the hardfacing not being properly welded to the parent metal as the parent metal surface was not sweating enough. I have seen several failures where stellite hard weld on a cam has come off in a slab because the parent metal was not hot enough to weld to the stellite hardfacing.

I have also seen stellite hard facing wear rapidly where it was applied with a tig and the parent metal contaminated the hardfacing.

It is possible that the hardfacing pads were brazed to the Norton followers to give a more consistent result than could be achieved by hardface welding by less skilled workers.

ando
Click to expand...

I found hardweld facing very difficult to apply consistently to a follower by hand. Everything has to be perfect and it's impossible to tell if it was perfect without destructive testing.

I would think that some of the new methods of applying hardfacing using a computer guided laser could work well.
 
SRM BSA followers after a few hundred miles use.
The cam/follower problems aren't unique to Nortons!
The cam looks ok, but I feel bad for the owner as all the grindings have gone thru the new motor.
 
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The cam lobe below the wrecked follower is ok, so that rules out oil starvation.
I think it has to be a soft follower.
It's going back to SRM for their analysis, will be interesting to see the outcome.

Glen
 
Wow!

Looks like a nice machining job at first glance!

Just a pity the cutting tool was the cam!!
 
Worntorn
Those are not BSA A65 followers. You can see they have a fat round body. Those are for an older model BSA motor. I'v never dealt with that kind of lifter so I don't know who supplied them to SRM or what material was used. Very odd for them to wear through one pad without damaging the cam. They may have used butter instead of stellite.
 
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Any update on AN followers?
I tore my engine down last Christmas, and planned on having it ready to ride at Daytona in March. It’s still down. I missed an entire (short Northern) season. It would be real nice to hear something.

A week ago, I came to the conclusion I had to stop the bleeding. I sourced another cylinder, (with standard lifter bore sizes, my original cylinder had lifter bores enlarged to suit the AN offered +.020" oversize lifters) got pistons fitted, and painted last night.
 
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