cam followers

Here you can talk about all kind of TECH for the B50 B44 B25 And Other BSA unit Singles

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vetterlatethanever
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Re: cam followers

Post by vetterlatethanever »

I given myself a 10% pay cut this year mark so does that mean I can get 20% off now? ;-)
stew79
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Re: cam followers

Post by stew79 »

firstly mark, i started down this long road to "2 cam followers" for my self, as you wernt making them, and advised me to find old stock for sale. then i found out about the "new ones" that were being made, that can snap as they must be made wrongly in some way ? to get my bike running again, with some confidence that it will still be reliable, is why i am here at this stage. the "bee hive" valve springs from rd in usa should be here next week which could take some load of the valve train (any improvement is going to help) .............. as for publishing the metal analysis results, that have just cost quite a bit, i think i will just pass them on to the cam company who will be making the finished parts. they have 50 + years experience in precision engineering, toolmaking, cam making, cam designing, cam grinding machine designing, cam grinding machine manufacture, prototype development work for all the major car, and some of the bike manufactures as well, and several world class racing companies. (f1, to world rally) i have no worries that they can deliver.
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Re: cam followers

Post by minetymenace »

stew79 wrote: as for publishing the metal analysis results, that have just cost quite a bit, i think i will just pass them on to the cam company who will be making the finished parts.
As moderator of the forum I'm sorry you feel that way and are not prepared to share the information here.

Sharing information and passing on knowledge is, after all, the raison d'être for this forum.
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stew79
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Re: cam followers

Post by stew79 »

hi minetymenace, when i have the finished parts in my engine, and all is well with the bike, i will publish the results from all the tests. including the hardness ones that are still to be done. you are right about passing knowledge for all on this site, but right at this moment me and my wallet are feeling a bit defensive, and need some time to calm down in a darkened room.
stew
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Re: cam followers

Post by stew79 »

its been a snapping good day, with unexpected results. the old bsa followers bent slightly and crack at about 1.3 tones. (the computer read out and graphs are all in kn,s with lots of extra detail) they are through hardened, from a very high carbon steel. (polgain will do further tests on the broken pieces to get a true carbon figure) the "new" followers are only case hardened from a low grade of steel, it bent more, and cracked in several places at a similar force ? the theory is that the new ones (case hardened) will flex more with use, and quickly develop stress cracks, then fail. the oil holes in the side are joined up by a 4mm hole drilled up from the base, before the pad is brazed on (quite a big diameter ?) so its over to the professionals to try and make some ?
stew
ps the "beehive springs" turned up from usa........... they seem to have sent the wrong ones as they are too long !!!!!
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Re: cam followers

Post by stew79 »

hi all, the final metal test results are in. the carbon content of one of the original cam followers is not as high as they first predicted. i have spoken to some of the engineering people at harris several times, and found them very helpful and informative. it would appear that my original followers are not made by bsa, triumph, or to any of there drawing specifications, upgrades, choices of steels, heat treatments etc. this is yet another twist in this long running quest just to get the dam bike running again. by the time i do hear it start again, i would have spent the equivalent of "3!!!!! good sized 3 bedroom houses" on development. but thats more than enough for some people. (like having a new cam in a race bike, but with smaller bumpy bits on it)
stew.
ps to be continued when funds are available.
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Re: cam followers

Post by B44Claus »

Good afternoon,

Rather than creating a new topic about cam followers I thought I might as well continue on this "old" one.

The (flat)followers in the B44/68 engine I'm building are worn and it was my original intention to scrap them as I have already bought new ones.
However, when I fitted the GP/MX cam I have acquired together with the new followers the cam wouldn't turn through all 360 degr. as the followers would hit the crankcase. With the old followers fitted the cam could turn without anything touching. It's not that this cam should use the radiused followers that has been checked.
Comparing the new followers with the old ones it's apparent that the new have a thicker "foot". The old are not just thinner due to wear they came that way originally. I can see that clearly from the unworn parts of the foot.
Now to my question: Can I grind/polish the wear marks away on the old cam followers to achieve an even surface again? The foot on the follower has a fairly thick(2-3 mm) pad brazed/welded to it and I will not need to grind through that to remove the scuffing marks. Is the pad hardened through or is it just the surface that's hardened?

Brgds,
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Re: cam followers

Post by lathejack »

I think the pad is made from Stellite, which will be hard all the way through. There is nothing wrong with grinding or polishing out the worn or scored surface, as long as it is not too deep, and the surface across the pads width is kept square to the stem.

I'm sure the later BSA cam followers did have thicker feet, and are usually refered to as big foot followers.
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Re: cam followers

Post by koncretekid »

I sand the followers on a heavy plate glass slab with sandpaper attached. Work your way down to 2000 grit and then polish them on a buffing wheel. Lastly, send those ugly big-footed ones to me for disposal.

I have never done extensive miles on my sanded and polished ones, but I don't see why we can't.

Tom
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Re: cam followers

Post by JB »

The thin ones are the earlier ones and the stronger thicker ones came along later, can't remember the change year, something like 1969?

It's worth mentioning that the stellite pad is not particularly hard; ones I've tested were in the high 40 Rockwell C range and yet they possess high wear resistance against the high loading of the cam. Also worth mentioning that the most important part of the cam follower, to avoid fractures, is the transition radius between the shaft and the foot, polish the radius out onto the foot as this is the area where all the stress is concentrated in hard use and is where they fracture and fail. If there's any damage or rust pitting to the ground radius... don't use them!
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Re: cam followers

Post by twinshocker »

Hello Claus,

i had the same problem with my CCM.
Grinded the marks on the followes away on a grinding machine, polished them and used them without any problems.
Make sure that the followers are fixed rectangular in the on direction and have the right angle in the other while grinding.
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Re: cam followers

Post by Ubert767 »

I had success in removing traces of wear on my B44 cam followers by using two grades of good quality diamond impregnated honing tools which are often used for the sharpening of wood chisels and the like.
Rob
Last edited by Ubert767 on Mon Nov 05, 2018 2:55 pm, edited 1 time in total.
B44Claus
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Re: cam followers

Post by B44Claus »

Hi guys,

Thanks for your replies and comments.

The followers didn't have any other visible damages than wear on the surface that contacts with the cam. Not a guarantee off course.
Based on your feed-back I ground the wear marks away on the followers taking good care that the surface remained perpendicular to the direction of movement of the follower. I ground them by hand on different grades of stones as I didn't want to risk damaging the mechanical properties of the stellite pad if overheated by grinding on a belt sander. Afterwards I polished it to a finish that is definitely better than the cam surface.
It took a couple of hours in total but I'm pleased with the result.

I also have a B25 and another B44 both 1969 models and neither have the thick foot followers. Perhaps they were introduced with the B50?

Brgds,
Claus
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JB
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Re: cam followers

Post by JB »

The OIF B25 & T25 production run was months before the B50, so it looks like the modified cam followers were introduced on the 250's first :???:
For some reason I thought they were introduced before the OIF bikes although I am not sure of that <201
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Re: cam followers

Post by midgie »

The later thick foot followers were fitted as std on the oif 250 singles. But I have found on a few of the very early examples the earlier thin foot type had been fitted from the factory. The b50 always used the thick foot type (71-2513) from the start.
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Re: cam followers

Post by DiggerB50 »

Hi Forumers, which of the available cam followers do peeps recommend? My exhaust one has just broken and I'd like to order one...
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