Author Topic: cam followers  (Read 3639 times)

Offline Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1430
  • Karma: 16
  • A kiwi with a racing A10 rig and too many projects
    • NZ Classic Sidecar Racing
Re: cam followers
« Reply #15 on: 03.07. 2014 01:38 »
Norton twin tappets are not flat either...
Tappets and cams are usually designed together with the quietening ramps design.  While I can see benefits in cam oiling improvement I would not be looking to amend cam follower geometry given 3 good performance cam options were available stock.
The cams certainly do clear the trough & scrub the faces so oils suitable for the cam design (high in zinc)  are preferred to reduce cam wear,
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline edboy

  • Valued Contributor
  • ****
  • Join Date: Oct 2012
  • Posts: 436
  • Karma: 3
Re: cam followers
« Reply #16 on: 06.07. 2014 14:53 »
unfortunately bert hopwood didnt have the benefit of hindsite which is where i hope these forums can help. i thought dunstal brought in the flatter [i dont know if there is a small radius there] camfollowers and transformed norton performance and i notice norton camfollowers suffer less wear than a10 ones. i am going to try the bevelled follower mod and let the site know how they wear in about 5 years hopefully. i m just surprised no one else has tried anything especially as cam followers seem short on the ground. in roy bacons bsa twins and triples book he states bsa designed the cam trougth to splash the big ends and then piston bores so i personally believe the more oil  into the camtrougth through the followers would also help cooling and lubrication on motorways etc. i may even try a triple oil cooler later on. also it seems to me that fresh oil is only delivered to the cam at high pressure via the prv or am wrong there?
on another note , i cant believe how well the follower faces have cleaned up with an oil stone. i will use the best flank on the opening side.

Offline Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1430
  • Karma: 16
  • A kiwi with a racing A10 rig and too many projects
    • NZ Classic Sidecar Racing
Re: cam followers
« Reply #17 on: 06.07. 2014 21:11 »
Norton cams would get better mist feeding from crank rotational spray, whereas the BSA one is masked by the trough, which relies on being filled with oil...while the cams tend to wipe it clear.
Certainly BSA twin cam followers wear is a bugbear as distinct to the beesa pre unit singles cam followers in the timing chect which never need touching
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline trevinoz

  • Newcastle, N.S.W. Australia.
  • Wise & Enlightened
  • *
  • Join Date: Jul 2006
  • Posts: 2903
  • Karma: 67
Re: cam followers
« Reply #18 on: 06.07. 2014 22:00 »
Norton cams also have a hard face.
I have had my followers ground and hardened and seem to be performing OK. Should have had the camshafts nitrided as well.
I tried flat followers over 40 years ago. Had them hard faced and ground. Didn't notice any increase in performance but had a lot of wear on the cam when I pulled the engine down after not a lot of miles.
I thought that Dunstall got the performance from a different grind camshaft to that of the standard SS cam.

Trev.

Offline Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1430
  • Karma: 16
  • A kiwi with a racing A10 rig and too many projects
    • NZ Classic Sidecar Racing
Re: cam followers
« Reply #19 on: 06.07. 2014 22:51 »
not wishing to turn this into a norton forum  *whistle* my last outfit was (norton) atlas powered and I certainly had radius'ed cam followers (which cannot rotate) and they wore  *sad2* too.
But my experience with the road rocket is that my A10 cam followers don't wear quite as well as those on the norton did.
Flat tappet motors like the a10 with heavy spring rates for sports cams will wear.
But certainly worth experimenting with reducing that. But I wouldnt see the slightly Norton design as being the solution
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline dynodave

  • crew chief
  • Moving Up
  • **
  • Join Date: Feb 2009
  • Posts: 12
  • Karma: 0
    • AGTS
Re: cam followers
« Reply #20 on: 07.07. 2014 01:26 »
not wishing to turn this into a norton forum  *whistle* my last outfit was (norton) atlas powered and I certainly had radius'ed cam followers (which cannot rotate) and they wore  *sad2* too.
snip

You certainly must be referring to an after market cam with modified lifters, since by 1963 all atlas' and the whole norton twin range had gone to  flat lifters. They did have radiused lifters as late as 1959 as in my 88 (500cc) engine. My 49, 51 and 52 norton engines are all radiused lifters.  I will have to check if the 650SS(1961) was flat or radiused.

In the most radical norton races cams the lifters are still suggested to be radiused.
dynodave
61 Gold Flash* 63 Super Rocket* 63 RGS

Offline Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1430
  • Karma: 16
  • A kiwi with a racing A10 rig and too many projects
    • NZ Classic Sidecar Racing
Re: cam followers
« Reply #21 on: 07.07. 2014 03:03 »
On the NOC site there are  discussion threads on flat vs radius'ed cam followers and I speak from recollection of the engines I owned and raced pre 2010. If my recollections are inaccurate I make no apology. Norton followers certainly do not rotate and the cams would be designed for that follower design. But I do recall wear on my Norton followers irrespective of their shape.

BSA used varying cam follower designs across the range. Some were better than others.


A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline dan daughenbaugh

  • A's Best Friend
  • ***
  • Join Date: Nov 2010
  • Posts: 84
  • Karma: 3
    • Greasy Gringo
Re: cam followers
« Reply #22 on: 10.07. 2014 13:26 »
This should take care of it! Someone craftier than me could whip these up.
50' BSA A7 Land speed racer
64' BSA A50C Scramble-ized
67' Triumph Bonnieville (stock)

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5456
  • Karma: 62
Re: cam followers
« Reply #23 on: 10.07. 2014 16:38 »
oh now just hold on there

as someone who is definitely not an engineer in any shape or form I would like to here some comment from those that are.
The rollers are half the width of the cam, they do rotate so wear there will be reduced but what is going to be happening a bit further in where the roller rotates in a fixed pin that has a wear surface much smaller than the roller to cam surfaces.
Would I be somewhere near to say at least a quarter of it so four times the load at that but then the pin is fixed so all the load will be on the top surface of it, I would be worried riding with those in - would I be a woos
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline edboy

  • Valued Contributor
  • ****
  • Join Date: Oct 2012
  • Posts: 436
  • Karma: 3
Re: cam followers
« Reply #24 on: 10.07. 2014 16:50 »
i believe newer harley davidsons use that design, type of cam follower but i bet theirs swim in oil and dont rely on splash feed.

Online chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 3260
  • Karma: 47
Re: cam followers
« Reply #25 on: 10.07. 2014 17:37 »
Hi All,
Vintage and speedway J.A.P. engines use roller followers and they seem to last well on total loss lubrication.
Indian Chief engines use the same setup, I am rebuilding two of these and the cams and followers do not require attention so it must be a fairly sound  design
By the way, Cams for roller followers are very much a different profile to "normal" cams

HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Offline Briz

  • A's Best Friend
  • ***
  • Join Date: Apr 2013
  • Posts: 209
  • Karma: 7
  • West Norfolk UK
    • Custom cycle developments
Re: cam followers
« Reply #26 on: 10.07. 2014 19:54 »
Roller-lifters are a mature technology Bill.  HDs have had them since the 1930s and so have many others. Most American V8s have had them since the 1980s.
They dont need to swim in oil! Splash feed is enough as it is on most roller-bearings.
But the cam profile does need to be designed for them and the cam needs to be hard enough. Adequately hard cams seems to be something that only the British bike industry struggled with!
Frictional loads are far less than a conventional follower. Harley cams never seem to wear out.
Another advantage is that you can design in much faster valve opening rates; you can get much more lift per degree of duration. Lots of lift without losing lower-end torque or idle quality.

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5456
  • Karma: 62
Re: cam followers
« Reply #27 on: 10.07. 2014 22:01 »
OK guys I'm sold

matter of fact I have a similar device for a replacement cam plate plunger in my Flash gearbox, had completely forgotten about it.
It came from Oz some many moons ago (1998 - 2000) maybe, anybody or remember who made/sold them, woo might have been one of us
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline dan daughenbaugh

  • A's Best Friend
  • ***
  • Join Date: Nov 2010
  • Posts: 84
  • Karma: 3
    • Greasy Gringo
Re: cam followers
« Reply #28 on: 10.07. 2014 23:20 »
That picture is the cam I'm running in my bike, the came was made in the 60s by harmon and collins. It was used when I got it, shows no wear and the rollers run on needles like a harley sportster. And yes indeed the cam looks like it has big square legos for lobes *smile*
50' BSA A7 Land speed racer
64' BSA A50C Scramble-ized
67' Triumph Bonnieville (stock)

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5456
  • Karma: 62
Re: cam followers
« Reply #29 on: 11.07. 2014 08:29 »
Quote
the rollers run on needles

ah now that's where I thought there would be a problem, obviously not then
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco