New (2020) Andover One-Piece Followers

The followers are 5g heavier than 70's items. This could be improved for those that want to lighten them.
Jim, you are very correct in your findings, but is the lobe wear separate to or a result of impact, yes the impact does not occur on the lobe. But from what I have seen suggests depending on your cam tappet combination the lobe wear can be the result of impact.
In the past the assumption seems to have considered that the worn lobe as it failed destroyed the tappet face. Could it be the other way around.

Madnorton said:

The followers are 5g heavier than 70's items. This could be improved for those that want to lighten them.

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So, with mine at 78g (from 650ss - all I have to hand at the moment) that's a 6.5% increase.
What sensible weight saving to you think is achievable - for road use, not race, although I'm sure some forum members would like that too!
...and what work would be involved (for each)?

robs ss said:

So, with mine at 78g (from 650ss - all I have to hand at the moment) that's a 6.5% increase.
What sensible weight saving to you think is achievable - for road use, not race, although I'm sure some forum members would like that too!
...and what work would be involved (for each)?

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Very little involved as the weight is in the base metal which is not iron, but you will need to be able to work special hard facing alloy. They were designed to be tough, not hard, to avoid being brittle. If anyone has successfully lightened a two piece tappet then what they did would work, how you would do it may be a problem.
The old two piece is a game of chance, they were furnace brazed and quenched, which causes varying rates of hardness from one body to another.

Madnorton said:

The followers are 5g heavier than 70's items. This could be improved for those that want to lighten them.
Jim, you are very correct in your findings, but is the lobe wear separate to or a result of impact, yes the impact does not occur on the lobe. But from what I have seen suggests depending on your cam tappet combination the lobe wear can be the result of impact.
In the past the assumption seems to have considered that the worn lobe as it failed destroyed the tappet face. Could it be the other way around.

Click to expand...

The spintron tests I made were at low/med RPM to eliminate impact. Anything is possible and I'm not saying I've covered everything. But I personally don't see impact being a problem with street RPMs.

Its usually the cam that shows the most wear - but its the lifter design or flaw that causes the cam wear (as Madnorton noted). Soft 850 Norton cams were at fault. Other than that the heavy flat Norton lifters are at fault. I've had reasonably good service with early style 750 cams and stock flat lifters. But I'm getting better longevity with the radiused BSA tappets - good enough to be happy with it.

I use radiused standard followers on a cam that has only 0.020'' less lift than the Sifton 480. The barrel was lifted after 4000 miles, all was good, and they have now covered 16000 miles.
Radius lifters I feel are the way ahead in no matter what form. The cam / follower envelope that makes up the boundary of the design lends itself to no perfect or ideal solution but I think the cam designed for use with radius followers enables more scope for better control of the system and better cam characteristics to used.
Jim C's testing gave a surprise finding when the tappets were etched and examined using a £250K microscope. I also sent a set of 70's tappets and these were also examined, to the naked eye they looked OK, had covered 27,000 miles.
Not this month, but I will put a feature together for AN newsletter, with photos of the surfaces examined.
The problem is that once failure is noticed it is usually so bad (pickup on sump plug) that the source or start of failure can't be seen.

The radius has to be better than flat and not rotating.

Why do the followers seem to get some form of point load at the lobe tip. (This one must be soft)

I think these were the followers out of my Mk2a but seem to remember the lobes had no obvious galling (but the T/S journal and bush were corrugated)
The finish probably looks worse than it is due to the camera.

Time Warp said:

The radius has to be better than flat and not rotating.

Why do the followers seem to get some form of point load at the lobe tip. (This one must be soft)

I think these were the followers out of my Mk2a but seem to remember the lobes had no obvious galling (but the T/S journal and bush were corrugated)
The finish probably looks worse than it is due to the camera.

View attachment 14488

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That happens to them all over time. It doesn't seem to matter what RPM. And you know the inertia forces and pressure timing peaks are changing throughout the RPM range.

jseng1 said:

That happens to them all over time. It doesn't seem to matter what RPM. And you know the inertia forces and pressure timing peaks are changing throughout the RPM range.

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Is ' That the groove in the centre/center ? ... The follower is bouncing or some weird chatter at full lift ?
Does a radius reduce that ?
I can't recall if Triumph (BSA) followers mark like that but the lighter weight might have some bearing on that.

I have seen that same mark on BSA Unit single flat footed followers.

I had a look at the radiused followers that came out of my 1957 TR6 (Original I do not know and marked R)
A faint flat at the centre but not bad for their possible age (weight 35 grams)

Time Warp said:

The radius has to be better than flat and not rotating.

Why do the followers seem to get some form of point load at the lobe tip. (This one must be soft)

I think these were the followers out of my Mk2a but seem to remember the lobes had no obvious galling (but the T/S journal and bush were corrugated)
The finish probably looks worse than it is due to the camera.

View attachment 14488

Click to expand...

Is the oil retaining "pocket" on top the camshaft on this engine still there, and has the engine being stood a long time?

Time Warp said:

The radius has to be better than flat and not rotating.

Why do the followers seem to get some form of point load at the lobe tip. (This one must be soft)

I think these were the followers out of my Mk2a but seem to remember the lobes had no obvious galling (but the T/S journal and bush were corrugated)
The finish probably looks worse than it is due to the camera.

View attachment 14488

Click to expand...

Quality photo, the tappet maybe soft or not, but it has worked. The indent is caused by one of two things, force against the tappet face or if not force then excessive wear at that point. The point you say about the cam being fine, confirms my suspicions that in the past the race for hardness on the cam and tappet were maybe not the best combination.
With impact usually comes work hardening, but not always, so not necessarily a problem in its own right. If it the impact does harden the surface then cracking is more likely to occur, if the cycle repeats and the cracking gets worse pitting will be evident, these bits that break away will score the faces.

It really is not straight forward, there is lot more understanding out there now which is good.

Time warp - you see the same groove on Triumph, BSA and Norton, but its worse on the Nortons because they have flat lifters. I also saw the same groove on the buckets of my dual overhead cam XKE Jaguar.

Its not caused by impact or clatter because you get the same groove when running at low RPM.

See my spintron vid at:
https://www.accessnorton.com/NortonCommando/spintron-demo-showing-norton-cam-lifter-wear.29763/

Near the beginning of the vid it clearly shows the line starting to happen at 1500 RPM. later in the vid it shows that the cam is only touching the center of the tappet when the cam is at peak lift.

Bernhard said:

Is the oil retaining "pocket" on top the camshaft on this engine still there, and has the engine being stood a long time?

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Not sure what a oil retaining pocket on Top of the cam shaft is but the engine case oil catchment/pocket ? under the cam would retain oil.
That bike only had 20000 miles on the clock so would have sat for long periods some time in its life.

The irony (If it is that) is that bike still needs a new set of followers or at least the good OEM replacement set I got refaced.
#
Follower problems are not just Norton.
On my 1973 Moto Guzzi (round followers that should rotate) it had the common pitted face on the R/H exhaust follower which can lead to the common worn lobe on that cylinder... replaced with a NOS cam and modern followers.
On the OHC Moto Guzzi prior to 2102 (iirc) with flat followers with a DLC coating on the face were failing (the coating) all but destroying the engine as the lobes wore away, they went to roller followers after that.