Cam and follower tests.

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It seems to me that as a Norton owner that I have two needs:

1.) a process by which I may eliminate faulty followers that may cause damage to my engine.
2.) the ability to source new followers.

It would be wonderful if the new followers didn't need to be tested for need number one, but ultimately if I can perform the first then we already have the second. This is not intended to be an argument on my part as to whether or not AN owes us QA. It is only intended to stress that figuring out how to eliminate faulty followers is a worthy effort. If for no other reason than the huge number of them now in circulation.

As for the first need, are the spigoted followers a big enough improvement to reduce the pad separation issue?

Russ
 
rvich said:
It seems to me that as a Norton owner that I have two needs:

1.) a process by which I may eliminate faulty followers that may cause damage to my engine.
2.) the ability to source new followers.

It would be wonderful if the new followers didn't need to be tested for need number one, but ultimately if I can perform the first then we already have the second. This is not intended to be an argument on my part as to whether or not AN owes us QA. It is only intended to stress that figuring out how to eliminate faulty followers is a worthy effort. If for no other reason than the huge number of them now in circulation.

As for the first need, are the spigoted followers a big enough improvement to reduce the pad separation issue?

Russ
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I would second the comments from Russ.

As a 'simple' Commando owner I am now concerned about the followers in my bike & anything I might fit in the future!

We seem to have two 'issues' in play:

1. Hardness of the follower pad in relation to hardness of cam lobes

2. Adhesion of pad to follower. This seems to be an issue steming back to the 'heyday' of Brit bikes and maybe a QA issue with the adhesion process that was never identified?

So, if I was to build a new engine and purchased a new cam & followers from whoever. Can I ask an engineering shop to check the hardness of the cam + followers AND is there a way of checking the adhesion of the pad? Is it just a visual inspection? as per Jim's pics? (looking for voids around the edges, poor installation etc.)

In the vast experience of the members of this forum are the tests I've mentioned, hardness & visual inspection of pad, run of the mill engineering tests or would you need to track down specialist firms to do this testing?

We could all send them to Jim & he could spend ALL his time testing our cams & followers, sleep is highly overrated ;-)
 
I have never seen a spiggoted pad separate from the body. [without a torch and a hammer]
 
Sorry, but I can't envision what a spiggoted follower looks like. Anyone got a pic?
Tnx, Jaydee
 
Rabbit hole.....pad adhesion, current manufacturing has 'solved' that issue, various have stated that in this thread and others.

The thread is about pad hardness, individually and as compared to cam hardness. Please stick to the point. Jim started by testing hardness and showing us results of that testing.

Let's stick with that for this thread!

Jim has also identified hard welded followers as a potential solution to the hardness issue, and that has brought in the need for earlier followers as donor parts, to be able to hard weld them, but it is now meaningless to begin to discuss pad adhesion on those followers.
 
There are a lot of OEM followers in circulation that may suffer from soft pads as well as pad adhesion. For those of us running those, this is an issue. Are you suggesting that we throw them away, or that we donate them to be hard welded?
 
jaydee75 said:
Sorry, but I can't envision what a spiggoted follower looks like. Anyone got a pic?
Tnx, Jaydee
Click to expand...

How about a crude drawing. Externally they look the same.

Cam and follower tests.
 
SteveA said:
Rabbit hole.....pad adhesion, current manufacturing has 'solved' that issue, various have stated that in this thread and others.

The thread is about pad hardness, individually and as compared to cam hardness. Please stick to the point. Jim started by testing hardness and showing us results of that testing.

Let's stick with that for this thread!

Jim has also identified hard welded followers as a potential solution to the hardness issue, and that has brought in the need for earlier followers as donor parts, to be able to hard weld them, but it is now meaningless to begin to discuss pad adhesion on those followers.
Click to expand...


Apologies, I went back to page one, post #16 about the spigotted design developed in the 80's that Jim explained!

So, hardness, hardness, hardness is the issue!

I'm in the same boat as Russ, I might have older style followers in my engine, it was already rebuilt before I purchased it & the original builder has passed on so I can't trace what followers were installed.
 
rvich said:
There are a lot of OEM followers in circulation that may suffer from soft pads as well as pad adhesion. For those of us running those, this is an issue. Are you suggesting that we throw them away, or that we donate them to be hard welded?
Click to expand...

I do not want them for donors for hard-facing.

The hardfacing I have done has been more of an experiment in compatible metals and hardness possibilities than a potential repair.
Hardfacing on small parts with a puddle torch like I have done is a difficult thing to get right and has a high failure rate. It is not a fast process.

Now if I had a lazer cladding machine it might be a possibility but I that's not likely to be in my future.
But I do know some people who could do it and I will do some checking to see if it might be equitable.

So if the followers have significant miles on them and the cam has not failed because they were soft and they have not fallen apart -then I would not worry about them.
 
I'm not advocating, just asking: Why can't the Stellite be applied by building up with weld rod? I have some Stellite 6 rods and have tig applied it to non-critical parts several times. It doesn't flake off ever, tough stuff.
Jaydee
 
And in the meantime the spintron has been howling away.

The 312a cam with 4 inch radius followers has been put to the test. Roughly 20 hours of runtime with the last 6 hours being at 6500 rpm with oil temps around 240 degrees. I am seeing early signs of distress.

It does not look too bad but if you look close next to the red mark you can see the beginning of a dent growing on the closing side of the follower. This corresponds with the pressure spike I see in the cam simulation software. Since this is pretty extreme operating conditions I don't expect a failure for quite a while but it is the beginning of wear and it is measurable.

Cam and follower tests.


Cam and follower tests.


Now for the nest test I installed a prototype asymetrical cam that I have been working on.

This cam has the same duration as the 312a w/4 in rad followers that was in the tester before but it has .025 more lift. The asymmetrical lobe design means the opening side of the lobe is different than the closing side. This lets you use one curve for opening and another curve for closing and get rid of some of the pressure spikes.

The cam software has shown this to be the case and the slow motion camera has shown the valve motion to be very stable.

So I finally decided it was time to risk it and spin it up to check for durability.

Here is a follower with the same harness as the first. The new cam was run though the same test sequence as the 312a was with the same head and springs.

The follower shows no sign of distress on the closing side and even the line through the center of the follower is much better. All the indications say this should be a winner. Now all I need to do is get it on the dyno. It will be in my new motor.

Cam and follower tests.


Now all I need is Ken's doorstop crankshaft to get back from the nitriding outfit and the new billet pistons to get here.
 
comnoz said:
The followers went from design where the pad was simply brazed to the bottom of a flat steel body to a spiggoted design where the pad fits into a depression in the bottom of the steel body. This solved the problem of spitting the pads. The change was made in the mid 80's as I recall.
Click to expand...

Jim, does it really solve the problem of spitting the pads? I do see the advantages but one disadvantage with this design is that you can't inspect the bracing joint anymore. What happens if the bracing bond fails? I can imagine a scenario where the lifter / pad passes the lope peak and is quenched out of the lifter body depression. Maybe I am just paranoid? :)

-Knut
 
jaydee75 said:
I'm not advocating, just asking: Why can't the Stellite be applied by building up with weld rod? I have some Stellite 6 rods and have tig applied it to non-critical parts several times. It doesn't flake off ever, tough stuff.
Jaydee
Click to expand...

It is easy with mild steel but,

The high carbon of the lifter body means you can not allow mixing the metals in the weld.
So two coats of different alloys need to be applied first. One that acts as a sealant and the next that is a wetting coat. They are done with spray-weld.

Then the actual hard coat is done with acetylene and rod.

The tig would be nice but it causes too much mixing and the hardness suffers.

Stellite 6 is too soft for the final layer although it works as a base.

Colmonoy 88 is used for the top layer. RHc62
 
mdt-son said:
Jim, does it really solve the problem of spitting the pads? I do see the advantages but one disadvantage with this design is that you can't inspect the bracing joint anymore. What happens if the bracing bond fails? I can imagine a scenario where the lifter / pad passes the lope peak and is quenched out of the lifter body depression. Maybe I am just paranoid? :)

-Knut
Click to expand...

I have never seen one fail by coming apart.

The one that I took apart with the torch was pretty tough to get apart. The spiggot seemed to be a pretty tight fit in the body.
 
Fascinating stuff there Jim and nice work. A couple of questions:
  • The little dimples I am seeing in the followers - are this from the hardness testing?
  • Can you get a watt meter on your motoring rig and give us a reading so that we get a sense of power required to drive the valve gear and pump?
 
Dances with Shrapnel said:
Fascinating stuff there Jim and nice work. A couple of questions:
  • The little dimples I am seeing in the followers - are this from the hardness testing?
  • Can you get a watt meter on your motoring rig and give us a reading so that we get a sense of power required to drive the valve gear and pump?
Click to expand...

Yes, the indentations are from the testing. I simply blocked them down with a diamond stone before I used them.
My 3 phase inverter will give me the KWH draw. I will have to see what it says next time I get it going.
I know the 4 horse motor is not exactly idling when it's running. With all the running it's done lately I'm sure my power bill will be pretty amazing.
 
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CanukNortonNut said:
Jim,
Were these cam followers in the salt flat engine used with your prototype asymetrical cam design? They look kind of that way to me?
Cheers,
Thomas
Click to expand...

Yes, trustworthy followers are in short supply around here....
 
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swooshdave said:
Is the asymmetrical cam harder to produce or more expensive?
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It will be the same price -after the master lobe and grinder masters are purchased.

I will need to complete dyno testing and if that goes well I have a couple options for masters.

Of course the prototype cam that I am beating on was a chunk of change.
 
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