Norton factory upgrade for cam followers

Back in the 1970s the Norton factory began upgrading their high RPM short stroke flat track motors to BSA type radiused lifters.

They did this because there was valve float problems with the heavy stock lifters and the extreme pounding between the stellite pad and the cam was beating up both the cam and the followers. They used a Sifton 460 cam that was designed for the BSA lifters. The lifter weight was cut in 1/2, the RPM increased, valve float and wear was reduced. Pounding and stress on the stellite pad was reduced.

In the Lightweight BSA cam followers post #4 Jim Comstock says: “They do seem to have a little better wear characteristics. They don't launch the valve train over the lobe peak as much so they don't wear the line across the center of the lifter as much as a flat lifter does..."

The reduction in stress makes it easier on the follower and less likely to knock off a stellite pad because a lighter BSA lifter doesn't need as much force to move it as a heavier stock Norton lifter does.

The photo below shows a Sifton 460 type cam lobe designed for BSA and Triumph radiused lifters as adopted by the Norton factory. If only Norton would have adopted this design for their production bikes they would have saved us all a lot of trouble. But economic reasons prevented it.



Ken Canaga is the one who first told me about the Norton factory going to BSA lifters and I was impressed when he explained the difference in wear etc between this setup and flat lifters.

Remember that any lifter - flat or radiused - should be carefully inspected under magnification for defects or imperfections. Quality control is everything.

Infomercial.

There is a lot of talk about lifters right now on this forum. What can be done about it???? How can we solve this problem???? The uproar started when someone had a PW3 cam wear out. OMG OUR CAMS ARE WEARING OUT!! People started pointing fingers at soft lifters etc. Everybody is suggesting solutions and a few are attacking Andover.

People forget that the Norton factory addressed this problem years ago and it worked.

What some haven't realized is that you can also give original Norton lifters the same tight radius as BSA lifters. You can't match the same light weight as a BSA lifter but you can match the longer lasting improved geometry of a 1-1/8" radiused BSA lifter. Some said it wouldn't work but the proof is in the photo below. There are Norton's running with radius cam design lobes and original Norton lifters machined to 1-1/8" radius as we speak and those lifter and cam combinations will outlast flat lifter cam combinations - everything else being equal.



I'm talking about a solution to the big problem that several threads are presently discussing. I have no problem talking about a better design - especially when the people at Norton came up with the idea. The purpose of this forum is to discuss problems and seek solutions - in this case the solution has been here all along.

The thing I loved about racing is that when the flag dropped, the BS stopped. Better riders on better equip always won the day. Others learned, went home did something about it and tried better next time.

Good to know, and interesting to boot, thanks for posting. Cj

JS,
Very good with excellent points. What is the average mileage numbers for those who have the BSA lifters installed for street bike running? Racing is great and puts hard facts to the conditions as stated above. Engine strip down is frequent in this environment. Not so for Joe average re-builder who just wants reliable no nonsense engine mileage.
So you sold some of these kits. To know how they do on the open road would be helpful and I am not talking of just your experience on your Atlas, Jim but others who have installed your product who ride. My guess is most don't do mileage... but I could be wrong. It would be informative if there is repeatable and consistent results with plus 30k on the odometer.
Cheers,
Thomas

Thomas
There are hundreds of Nortons on the road with BSA lifters now. I don't know the milage and they would have to be the ones to give witness for it to really have meaning. It would be great to hear from some of them.

jseng1 said:

There is a lot of talk about lifters right now on this forum. What can be done about it???? How can we solve this problem???? The uproar started when someone had a PW3 cam wear out. OMG OUR CAMS ARE WEARING OUT!! People started pointing fingers at soft lifters etc. Everybody is suggesting solutions and a few are attacking Andover.

Click to expand...

IMHO this so called (stock) lifters problem is greatly exaggerated. Yes there have been some reports of a lifter that lost the stellite tip and it seems that some type camshafts are bad hardened (mostly stock MK3 cams and todays PW3 cams). Fact is I have been racing for about two decades with Norton twins using stock (steel, not chilled iron) Norton cams, Dunstall, Somerton always in combination with stock flat (lightened) lifters. On the road I guess I did about at least 200K on several Nortons so far. I NEVER lost a stellite tip or experienced a badly worn lifter surface (of course did some re-facing on lifters when changing cams). Most of my Norton friends over the years share my experience. Today for racing I would probably use the lighter BSA style lifters and JS-cams (as far as I know the only supplier of cams for BSA style lifters) however for road use I will always stay with stock flat lifters to use for most camshafts widely available on the market.

I agree the tone is amplified beyond reasonable levels.
But on the bright side, it seems to have sparked a rather comprehensive and real-world oil-testing regimen on the part of Mr. Comstock, for which we will probably be most grateful.

I fitted JS #1 cam and follower kit in the winter of ‘13.

I’ve been very happy with it all. No worrying wear when stripped in the winter of ‘16 and still in there currently.

The bike hasn’t accrued steady high mileage though, even though it’s a road bike, it’s led a life closer to that of a race bike thus far.

Norton speed
Like you - I never had a stellite pad come off a Stock Norton lifter - even when racing. But I still appreciate the upgrade that Norton came up with - especially if it makes street cams last longer (with broader nose).

My bike ran about 25,000 miles before one of the stellite pads popped off while at an idle in my driveway. Luckily, I heard the clanking start and shut the bike down. Without a lot of people using those BSA followers for a lot of miles, it's hard to know if they are any less of a ticking time bomb than the stock lifters can be. Given the fact that it took my lifters over 20,000 driven miles for one of them to fail, it's not a flaw that kills a brand new bike in it's youth, but I'd still like to sort it out... as would all of us who have had an issue where lifter failure caused their rebuild.

As far as being "greatly exaggerated", I disagree. It's an important, real issue. Perhaps the original lifters can work perfectly for 100,000 miles IF they are oven brazed properly, are of sufficient hardness, and the correct motor oil is used. I only have control of the last element, but not the first 2. I have to take the quality of those parts on faith, unless I get a modification that eliminates the problem. Needless to say, those of us who have had lifter failure see the issue as more likely than those who haven't had a delamination.

If removing my lifters to have the joint between the body of the lifter and the stellite pad ground back and reinforced with a weld at the seam would guarantee they will not delminate I would do that. The worst aspect of this issue is that a relatively inexpensive part fails often enough to not be a very rare occurance and it usually causes expensive damage to the engine. I don't think many people would leave the stock lifters in their engine and take their chances, if there was a way to modify them to be bulletproof.

As far as Jim Schmidt's BSA lifter swap goes, I think many of us who have had this issue, don't want to spend $1000. without knowing if his lifters are any less likely to delaminate than the stock ones. Certainly a lighter assembly puts less force on the moving parts, so the physics points to the BSA lifters taking less of a hammering based on their lighter weight alone.

I'm not looking for higher performance, I just want a bulletproof lifter.

I used to ride Tri-BSA back in the day. Never had a problem with their lifters. Which proves nothing.

I thought I understood from a different thread that the BSA lifters supplied in Jim’s kits are from SMR and hard welded. Is this correct? If so pad delamintion is unlikely. I thought I also understood that SMR is no longer making these. Is that correct?
If so the supply is limited.

Onder said:

I used to ride Tri-BSA back in the day. Never had a problem with their lifters. Which proves nothing.

Click to expand...

Yes, ‘prove’ may be too strong a word here, but to answer o0norton0o’s question, BSA and Triumph sold many times more bikes than Norton. BSA and Triumph lifters are very similar (the BSA ones having a thicker shaft). And although this failure has happened, it is very rare and certainly not something that occupies the minds of Tri-BSA riders. So it is surely a way of reducing the chances of failure in a Norton even further?

But I wouldn’t say this would be a reason to buy the JS kit, more of a pleasant additional side effect.

Yes the supply of SRM hardwelded BSA lifters has dried up and they don't plan on making any more.

I have tried the hard welding - it goes on with a torch and its no fun. The pros at Web cam seem to pull it off just fine for their hard welded cams - but they do it every day. Below is a hardwelded cam with the sides trimmed off and ready for grinding.



Removing pads from lifters and hardwelding them would be expensive and a grinding jig needs to be setup for grinding the sides. I think its true that BSAs & Triumphs don't have an issue with pads coming off as often as Nortons do and I never saw it happen during my young years at a BSA shop.

I applaud anyone who offers a product for our bikes and I want them to start threads about what they are offering. This site would less valuable to me, and likely to most everyone else on here, if they didn't. Threads such as this one promote discussion and often enlarge the knowledge base of readers. Always a good thing.

I have used flat followers with race cams in 650 Triumph engines. I felt I gained improved performance, however I was always changing other things at the same time. As the cam lobe progresses across the follower, the contact point does not necessarily start at one edge of the follower and progress to the other. So unless you plot the cam profile in degrees verses lift, you have no idea whether the profile has changed much by fitting curved followers in place of flat or vice versa. I suggest it would take a lot of theorising to determine what is the most suitable profile for the various combinations of four-stroke motors, so most of what guys do is 'suck it and see'. To my mind, flat followers should give a more savage lift rate, but I could be very wrong.

jseng1 said:

Yes the supply of SRM hardwelded BSA lifters has dried up and they don't plan on making any more.

I have tried the hard welding - it goes on with a torch and its no fun. The pros at Web cam seem to pull it off just fine for their hard welded cams - but they do it every day. Below is a hardwelded cam with the sides trimmed off and ready for grinding.

Removing pads from lifters and hardwelding them would be expensive and a grinding jig needs to be setup for grinding the sides. I think its true that BSAs & Triumphs don't have an issue with pads coming off as often as Nortons do and I never saw it happen during my young years at a BSA shop.

Click to expand...

Jim, the option of using explosion forming is still on the table. With this method and given a sufficently large jig, 50 followers could be "welded" in one go. Then a grinding prcess would be needed, which can be automated. I believe this is a recipe to get around the big spenditure SRM envisages. I'd love to try this out but my time is very limited at the moment.

-Knut

I am all for an improved pad wether its explosive formed or hard welded. I've tried the hard welding but thats all. The problem is simply spending the time and money to actually make it happen. The need is there and thousands of BSA owners would gobble them up. Norton style lifters would be more difficult and more expensive and that may make the conversion to BSA lifters more attractive.

Today I'm working on a spintron assembly to determine the cause of some specific wear I've seen on lifters. We'll see how far this goes.