ronnierockets
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« on: 12.05. 2009 22:20 » |
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hi all,
I was recently given, a thick flanged barrell,in very good nick ,but with slight damage to the bores,however after a visit to a machine shop, the bores cleaned up nicely to +60,which suited my 'rockets existing pistons.
so as i wasn't completely happy with the thin flanged barrells that i was already using, (some broken fins ect) i deceided to swap barrells.
when i removed the cam followers, (with less than 500 miles on them) from my superrockets thin flanged barrells,i discovered them to be badly scuffed ,but on inspection of the camshaft lobes, they dont seem to be as badly marked. i had no trouble dressing up one of the followers surface using 240 grit sandpaper on a flat surface,
i would of thought that its surface would have been a lot harder, so to my question, are my aftermarket followers a bit on the "soft side" ?(krap),
has anyone else been down this road?
the first pic. shows the follower that i dressed alongside one of the scuffed ones
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as the wife says,too many bikes, and only one butt.
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ronnierockets
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« Reply #1 on: 12.05. 2009 22:24 » |
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sorry lost first pic.
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as the wife says,too many bikes, and only one butt.
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a10gf
West Coast, Norway
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« Reply #2 on: 12.05. 2009 22:49 » |
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They should last way more than 500 miles, can't be that bad metal quality   (made of lead, maybe. lol). Lack of oil in the area for some reason? Large metal particles in the oil ? Cam lobes looking good? then it could be the followers' metal\hardening. |
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A10 GF '53, Triumph 900 Legend, Yamaha XT500  Norway - Bergen |
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BSA500
A's best friend
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Tonbridge,Kent,UK
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« Reply #3 on: 13.05. 2009 09:47 » |
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I have had two sets do that on my A7 I am hoping the ones I have in now are better  |
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fido
Zala County, Hungary
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« Reply #4 on: 13.05. 2009 13:55 » |
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Perhaps get some from SRM and see if they are better.
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A10Boy
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Solihull, Near Birmingham England.
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« Reply #5 on: 13.05. 2009 16:37 » |
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Cam followers are usually "case hardened", or stellite tipped, anything which is hardened wont scuff like that and you wouldn't be able to clean them even if they did, they would be too hard.
Looks like you got some soft rubbish there.
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Regards Andy 1960 A10 - Black Golden Flash 1973 Z1a - Fast 1960 AJS Model 31 CSR - Beauty  |
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ronnierockets
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« Reply #6 on: 13.05. 2009 20:39 » |
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Hi fellas, thanks for your imput,
i purchased the scuffed ,(crappy) followers from a supplier in Nottingham .
I have since contacted SRM about their camshaft and 'followers, and they tell me that neither will
be available until they'r finished testing both products, which will be about mid June ,
so it looks like i'll have to sit tight till then, pity in a way, as i was looking foward to bringing the 'rocket across the "pond" ,on the 22nd of this month, to attend the "welsh Irish Rally".
So it looks like its the Nortons turn this time.
As it would happen, my friend Tom, is having his "firebird" engine worked on by SRM,and as we arrive a day early for the rally, we have arranged to visit the SRM workplace.
so i might have some interesting photos for the forum, when i return from my trip.
thanks to all... Ronnierockets..
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as the wife says,too many bikes, and only one butt.
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A10Boy
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Solihull, Near Birmingham England.
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« Reply #7 on: 13.05. 2009 21:33 » |
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Regards Andy 1960 A10 - Black Golden Flash 1973 Z1a - Fast 1960 AJS Model 31 CSR - Beauty |
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ronnierockets
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« Reply #8 on: 13.05. 2009 21:56 » |
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hi andy,re SRM's web page on Stellite cam followers,it gives a phone no.to order,which i did, to be told by a member of staff ,that they wont be ready to purchase till about mid June,same applies to the superrocket camshaft. best regards..Ronnierockets..
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as the wife says,too many bikes, and only one butt.
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BSA_54A10
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« Reply #9 on: 15.05. 2009 03:12 » |
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Then get your current ones hard faced and reground.
Most shops that grind cams ( for cars) will have the facilities to hardface your followers and regrind them to the original profile .It is stock & trade for most of these places and usually the local place where you are liable to bump into the owner in the pub that will do the best job for you.
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Bike Beesa Trevor  |
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rocket man
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« Reply #10 on: 16.05. 2009 15:34 » |
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hi mate hang on for the followers from srm
ive been to srm nice bunch ove lads good quality
work they did all my engine and gearbox work
top job theres a lot ove poor quality stuff out there
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ronnierockets
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« Reply #11 on: 17.05. 2009 12:27 » |
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hi BSA-54a10, and rocketman, thanks for your advice,
Now i never turn down a suggestion to visit the pub,...Lord no..
But i dont think i'll bother to get the "crappy" followers hardened ,i dont think it would be worthwhile.
i'll just wait for a decent set, from SRM, as all their products seem to be well made, and of a good quality .
Best regards..Ronnierockets..
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as the wife says,too many bikes, and only one butt.
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dpaddock
NC, USA
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« Reply #12 on: 17.05. 2009 16:53 » |
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Some thoughts:
The A7/A10 has a "part-time" cam oiling system, as one wag has put it. This is because the cam surfaces are oiled directly only when the pressure relief valve lifts. Otherwise, they depend on oil being flung off the crank journals which, by design, get priority.
The followers have a foot radius of 1.25 inches and a foot hardness of 62 Rockwell C. This is pretty hard, and any scoring/scuffing is because of a paucity of good lubrication there. Contemporary engine oils lack the slipperiness of period oils since such additives tend to poison modern catalytic converters.
All cam followers act to remove the lobes of their cams, especially non-rotating followers in the presence of poor lubrication and dirt. Bear in mind that followers are cheaper than cams and that fresh oil is cheaper than followers. This suggests frequent oil changes and the use of a modern filtering system. Adding a dab of STP or similar slippery oil enhancer is also a good idea.
By all means, go ahead with your replacements but consider the foregoing.
David
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David '57 Spitfire  |
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