longer lasting camshafts

jseng1 · May 6, 2018

There have been a lot of complaints on this forum about worn camshafts. There are two ways to make a cam last longer - hard weld and regrind the lobes as webcam does in the image below. This works fine but requires a donor cam core.

Another option is to make a new billet steel cam and case harden it with plasma nitriding (better than regular nitriding). Its an added expense but works very well. See batch of plasma nitrided cams below (not available from most suppliers unfortunately).

These are not the cheapest cams you can buy. They cost more but they do last longer.

Joe Schlaberdowski · May 6, 2018

How do you know excessive cam wear has begun? Do you wait for a fall off in prformance? Or regular compression testing? Possibly one side is affected first?

acotrel · May 6, 2018

If your cam has a more aggressive lift rate, does it wear quicker ?

oldmikew · May 6, 2018

Surely 1 inch radius curve will go through the cam lifters hardening .. Must admit JAS 1 seems good.. What about the profile of JasO this is the streetcam you advertise?

Madnorton · May 7, 2018

What's long life, there is an owner in the UK that gets 80,000 miles out of his standard cams, as that is the interval he rebuilds the engine - yes, now completed it's third re-build. Irrespective of how good the cam is made or from what, poor installation will wreck any cam. How long will these cams last, someone must have done of 40K miles to persuade me that the extra tech and coating is worth it.

Fast Eddie · May 7, 2018

That’s a fair point Mad. IF that’s the intended purpose.

I learnt a while ago that different uses have different stresses.

A high mileage ‘sensibly used’ road bike will wear cams differently to a low mileage ‘thrashed to within an inch of it’s life’ bike, like racer or an abused road bike!

Mine falls into the abused category, and experience had led me to prefer hard welded cams.

All only IMHO of course.

ewgoforth · May 7, 2018

As best i can figure out I have 113,000 miles on my 1973 Commando. It had 9000 miles on it when I got it. Although i was just thinking I might have another 10,000 miles on it, it's hard to know for sure as I'm on my fourth speedometer.

Most of that with the original cam (which is in it now). I did run a megacycle 56000 for about 20000 or 30000 miles until it died. I think a broken inner valvespring may have caused that.

Because of my installing the Megacycle cam early in my ownership, I've run RD valve springs which may have helped cam durability. I don't know how they compare with stock as far as rate.

Madnorton · May 7, 2018

Fast Eddie, exactly, what you want it for and expected life are something some owners need to get to grips with. hard facing is very good, expensive and does need any coating - with current application methods I would suggest nothing could beat it, it also gives consistency as the hard face material can only be at the worst its lowest hardness no matter how it is applied. You can also get material that will not scuff and gal at temperatures far higher than found in Norton engine, so if you lose lubrication the cam and follower have a better chance of surviving.
Don't get me wrong, there are some very trick coatings out there, but I have not met one yet that is suitable for a long life Norton cam, other cams yes, but not a Norton - as you would know, I would have checked them out and tested them if the boffins suggested that they were fit for that purpose.

lcrken · May 7, 2018

oldmikew said:
Surely 1 inch radius curve will go through the cam lifters hardening .. Must admit JAS 1 seems good.. What about the profile of JasO this is the streetcam you advertise?

I didn't see any mention in this thread of radiusing a stock lifter to 1", which, as you say, is not possible. What am I missing here?

All the Norton cams I've seen that use that small a radius on the lifter (including the JSmotorsport ones) use BSA A65 lifters, which are 1.125" stock, and are regularly ground to tighter radii. I'm currently using a set ground to .875" with an N480 cam.

Ken

oldmikew · May 7, 2018

Ken

I must have missread Jseng;s website... JAS 2 requires BSA A65 lifters For JAS 1 website talks of reprofiling customers existing followers

jseng1 · May 7, 2018

Ken and oldmikew

see photo of stock lifter reground to a 1-1/8" radius. I didn't know this would work until I tried it. There is still plenty of stellite and because of the geometry of a radius cam the wear patch still does not approach the ends of the stellite. In fact the remaining stellite pad is longer than on BSA lifters.

And yes the JS0 is a street cam with performance similar to a stock Norton Commando cam. Maybe the slightest bit of more pep.

The photo above shows the same lifter Xs 4 that was pasted together in photoshop. You can see that the factory brazed the stellite pad on a tilt and so the pad extends further one direction - probably a factory mistake, but it still came out OK. The stock lifter is a lot heavier than a BSA lifter but you can use the stock pushrods and not have to add the tappet blocks for the BSA lifters. Not as good but more economical for street bikes.

acotrel · May 7, 2018

Don't variations in the shape of the lifter change the lift profile of the cam ? Are there different shaped lifters for various Commando cams ? I notice in photos that the BSA type lifters appear to be radiused rather than flat.

Fullauto · May 7, 2018

Madnorton said:
Fast Eddie, exactly, what you want it for and expected life are something some owners need to get to grips with. hard facing is very good, expensive and does need any coating - with current application methods I would suggest nothing could beat it, it also gives consistency as the hard face material can only be at the worst its lowest hardness no matter how it is applied. You can also get material that will not scuff and gal at temperatures far higher than found in Norton engine, so if you lose lubrication the cam and follower have a better chance of surviving.
Don't get me wrong, there are some very trick coatings out there, but I have not met one yet that is suitable for a long life Norton cam, other cams yes, but not a Norton - as you would know, I would have checked them out and tested them if the boffins suggested that they were fit for that purpose.

A number of inaccuracies here. You're in for a shock.

lcrken · May 7, 2018

jseng1 said:
Ken and oldmikew

see photo of stock lifter reground to a 1-1/8" radius. I didn't know this would work until I tried it. There is still plenty of stellite and because of the geometry of a radius cam the wear patch still does not approach the ends of the stellite. In fact the remaining stellite pad is longer than on BSA lifters.

And yes the JS0 is a street cam with performance similar to a stock Norton Commando cam. Maybe the slightest bit of more pep.

The photo above shows the same lifter Xs 4 that was pasted together in photoshop. You can see that the factory brazed the stellite pad on a tilt and so the pad extends further one direction - probably a factory mistake, but it still came out OK. The stock lifter is a lot heavier than a BSA lifter but you can use the stock pushrods and not have to add the tappet blocks for the BSA lifters. Not as good but more economical for street bikes.

That is good info, Jim. I have always assumed you couldn't do that because it would grind through the Stellite. I never thought about where the wear area was. I'm a little embarrassed about that. Still, I think I'll stick to the BSA lifters with cams designed for the smaller radii, even if it is just for the weight reduction, although I am using radiused stock lifters with a Webcam in one of the street bikes. Always good to learn something new.

Ken

acotrel · May 7, 2018

If you look at the wear pattern on the flat lifter and consider where the contact point is with the cam as it rotates, you will probably see that different shape cams make contact where the spring loads are greater or smaller. With flat followers and a standard cam, the initial loads are probably greater due to the cam lift rate, but smaller because the valve spring is less compressed. With a Commando, it is easy to get more power over-all by using an aggressive race cam to raise the operating rev range. More torque in the midrange is a safer way to go and probably just as productive.

longer lasting camshafts

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