Norton Twin, Oversize Cam Followers: Anyone know of a supplier?
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Shelby-Right
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There is a Andover norton video on you tube and ash talks about the method of sizing these to fit , suggesting they could be quite a neat fit , maybe ring them , see if this would be enough to fix your barrel or request some .002" or what ever , in finished size . Maybe they can do this .
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We used to supply oversize cam followers but with our new, one-piece variant these are no longer possible. The old ones were ground to size with oversize castings offering the opportunity to grind them oversize.
Eventually nobody was prepared to grind them for us anymore, the two different material, body and tip, being a major issue for the grinders.
Took us a couple of years to come up with the current solution, involving material research by a major automotive supplier who came up with a suitable steel alloy that suits the various camshafts in the market after several attempts, but these are now precision cast to far tighter tolerances.
Eventually nobody was prepared to grind them for us anymore, the two different material, body and tip, being a major issue for the grinders.
Took us a couple of years to come up with the current solution, involving material research by a major automotive supplier who came up with a suitable steel alloy that suits the various camshafts in the market after several attempts, but these are now precision cast to far tighter tolerances.
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The good news/bad news is the new followers are very expensive, which gives you a large budget window for alternative solutions. This "budget" should cover Kommando's suggestions: coating/plating your existing followers, or sleeving the bores. I wonder if Jim Schmidt's bronze lifter blocks for BSA lifters might help. Maybe available oversize?
Fast Eddie
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Unless you’ve bored the tunnels out, these are the perfect solution in these circumstances!The good news/bad news is the new followers are very expensive, which gives you a large budget window for alternative solutions. This "budget" should cover Kommando's suggestions: coating/plating your existing followers, or sleeving the bores. I wonder if Jim Schmidt's bronze lifter blocks for BSA lifters might help. Maybe available oversize?
The lifter blocks do not care how horrid the tunnels are. They get clamped and loctited into place.
Shagged out tunnels are the perfect excuse !!
Britstuff
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Thank you for your reply.The good news/bad news is the new followers are very expensive, which gives you a large budget window for alternative solutions. This "budget" should cover Kommando's suggestions: coating/plating your existing followers, or sleeving the bores. I wonder if Jim Schmidt's bronze lifter blocks for BSA lifters might help. Maybe available oversize?
I am certainly open to Kommando's suggestion. The problem is I need to find someone to do the work.
I would be more than happy to use Jim Schmidt's cam followers, (my bike currently has his pistons and rods). The problem is, (unless I am mistaken) that you have to use Jim's camshaft. Such would mean splitting the cases and replacing the excellent condition cam already installed.
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Welcome to the inner sanctum of Nortondom. Where even your problems have problems.......
If you don't want to split the cases or change the cam, your options are limited.
Have you visually inspected the lobes and measured total lift, reassuring yourself that the cam is still good?
You should also measure the lifter bores and the lifters. Perhaps the wear is in the bore and new lifters alone will fix the problem?
Depending on how worn/chewed the lifter bores are, plating/coating the lifters may solve the problem. This introduces its own complexities. As in, how thick, and with what? Following up on Ashley's video, I don't think I would want to be "linishing" a plated or coated lifter.
If you don't want to split the cases or change the cam, your options are limited.
Have you visually inspected the lobes and measured total lift, reassuring yourself that the cam is still good?
You should also measure the lifter bores and the lifters. Perhaps the wear is in the bore and new lifters alone will fix the problem?
Depending on how worn/chewed the lifter bores are, plating/coating the lifters may solve the problem. This introduces its own complexities. As in, how thick, and with what? Following up on Ashley's video, I don't think I would want to be "linishing" a plated or coated lifter.
cliffa
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Why wouldn't they work on a standard cam?
Fast Eddie
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The standard Norton cam profile is not designed to work with the radius on the BSA followers.
And (I believe) the BSA follower is not long enough to work if ground flat.
t ingermanson
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Earplugs seem like a pretty good fix for slightly rattly lifters given your acceptable options otherwise.
No offense intended, but how deep is this rabbit hole, and what exactly are you fixing when you get to the bottom? You're looking for a "quiet" Norton?
If the cure is worth the price of the medicine, any old school automotive machine shop should be able to do this for you. Cast iron is available in round bars to be turned and bored to whatever diameter you want for a liner, and a rebore/hone of the lifter tunnel is (hopefully) well within any of those shops' abilities. Call around to local shops; it's a technically simple job.
All of this seems like an absolute self-imposed headache, when Jim's BSA lifter block is an over-the-counter fix. Price-wise, probably a toss up, but one can be done in a weekend with almost zero risk.
My thoughts keep returning to the earplugs that I wear anyway.
No offense intended, but how deep is this rabbit hole, and what exactly are you fixing when you get to the bottom? You're looking for a "quiet" Norton?
If the cure is worth the price of the medicine, any old school automotive machine shop should be able to do this for you. Cast iron is available in round bars to be turned and bored to whatever diameter you want for a liner, and a rebore/hone of the lifter tunnel is (hopefully) well within any of those shops' abilities. Call around to local shops; it's a technically simple job.
All of this seems like an absolute self-imposed headache, when Jim's BSA lifter block is an over-the-counter fix. Price-wise, probably a toss up, but one can be done in a weekend with almost zero risk.
My thoughts keep returning to the earplugs that I wear anyway.
Britstuff
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I appreciate your candor!
I actually have been tuning it out for the last few years. This current situation came about because, stupid me, I went and bought another Norton, ('74 Commando) and now she is finally roadworthy, she is ever so much more mechanically quiet!. The noise from the Dominator's cam followers now fill my restless nights and haunt my every waking moment. I have no choice, for my own sanity they must be tamed!
Got a lead from someone today regarding the very type of machine shop you describe. It does seem the best way forward for me, (as I do not want to change my camshaft) is to re-line the cam follower bores to suit standard size cam followers.
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You will probably need to split the cases for the machine shop to do the job.
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I bought the complete cam, pushrods and radiused follower kit from Jim Schmidt early this year because of the ridicules cost of new Norton followers, with no oversize available and camshafts.
The cam I chose was the JS0 road cam. I thought the follower fit in the bronze bodies was a little too slack, however after following Jim's instructions for setting the valve clearances the noise levels dropped to a rustle at tick over to silence when riding. The JS0 cam for me was a great choice. The motor is easy to start, smooth tick over, free revving and pulls like a train. Fingers crossed it will see me out.
Thanks Jim.
The cam I chose was the JS0 road cam. I thought the follower fit in the bronze bodies was a little too slack, however after following Jim's instructions for setting the valve clearances the noise levels dropped to a rustle at tick over to silence when riding. The JS0 cam for me was a great choice. The motor is easy to start, smooth tick over, free revving and pulls like a train. Fingers crossed it will see me out.
Thanks Jim.
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BSA lifters must be radiused. If they are ground flat then the cam would hit the edges of the lifters. The Cam is designed for the radiused lifters and has a rounder nose. This is why cams designed for radiused lifters last longer - because cams for flat tappets have a pointier nose and higher wear factor. Ken Canaga was the first to explain this to me. Our flat tappet racing cams were beaten to death after a season of racing but Kens radiused lifter cams still looked good. The factory Norton flat trackers in the US went to BSA lifters and wilder cams to get more HP. With radiused lifters you can go all the way up to a Sifton 480 cam (JS4) and thats about as high performance as you can get.
Look at the roundish nose on the used cam for BSA lifters in the photo compared to a pointy nose flat lifter cam.
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Fast Eddie
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The JS#1 cam in my 850 had some serious (ab)use and is unmarked. I did have to get the followers reground once. Considering the normal cam / follower wear issues that Nortons seem to suffer, I thought this was outstanding !
Buying a new barrel may be a better option? They are offered by Norvil. If you have to reline the barrel in the foreseeable future as well, relining the cam follower tunnels doesn't make sense from a financial point of view.
- Knut
Britstuff
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Hi Jim:
I was hoping you would chip in at some point. I certainly get what you are saying about radiused cam follower ends and broader camshaft profiles being superior. If I was smart I would have installed your modified BSA lifters and cam shaft when I had the motor apart. However, I did not. This motor runs your lightweight pistons and rods, my Commando runs a set of your pistons. Both are excellent!
While clearly not the optimum configuration, can you confirm whether your BSA lifter setup can or cannot work with a non JS camshaft? Naturally part of the answer depends on how broad the camshaft lobes are. I believe mine are a bit wider than standard, my cam is supposedly a longer lasting type I purchased from Norvil, that I think has wider lobes, (maybe not as wide as yours). One useful clue may be the wear pattern on my existing cam follower pads. Somebody apparently radiused them, the wear patterns seem to suggest the width of the contact marks.
Truth be told. I would prefer to use your BSA lifters. Lighter, probably a lot quieter, I don't even need the help of a machine shop to install them, (although getting the height right clearly takes some thought).
Thank you!
I was hoping you would chip in at some point. I certainly get what you are saying about radiused cam follower ends and broader camshaft profiles being superior. If I was smart I would have installed your modified BSA lifters and cam shaft when I had the motor apart. However, I did not. This motor runs your lightweight pistons and rods, my Commando runs a set of your pistons. Both are excellent!
While clearly not the optimum configuration, can you confirm whether your BSA lifter setup can or cannot work with a non JS camshaft? Naturally part of the answer depends on how broad the camshaft lobes are. I believe mine are a bit wider than standard, my cam is supposedly a longer lasting type I purchased from Norvil, that I think has wider lobes, (maybe not as wide as yours). One useful clue may be the wear pattern on my existing cam follower pads. Somebody apparently radiused them, the wear patterns seem to suggest the width of the contact marks.
Truth be told. I would prefer to use your BSA lifters. Lighter, probably a lot quieter, I don't even need the help of a machine shop to install them, (although getting the height right clearly takes some thought).
Thank you!
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Britstuff
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Hi Knut:
Yes, I see that Norvil does have a new spigoted barrel for sale. It is indeed an option. Although I hate the idea of buying it and immediately boring it .040 to suit my existing pistons. Seems a shame, so I would have to consider buying a set of std pistons and rings, followers and the new barrels. Definitely not the cheapest option! Also, I do not need to rebore or hone the piston liners on my existing barrels. Said was done about 2,500 miles ago and are still good to go. Same with my camshaft, which is why I was hoping not to have to swap it out.
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