Regarding the published PW3 Cam lift figure of .380, it is important to know how the lift is/was measured. From my experience, in the US, some Cam Grinders measure from "0.00" on the base circle of the cam and publish a total lift number, while others measure from .050 "up the ramp" from the base circle 0.00 and publish that number. The PW3 lift number of .380 struck me as a little light and I would suspect this may be the case. if you add .050 to .380 you get .430 which seems more in line with the other Cam published lift numbers.
Re: Norton Racing camfollowers#65883 08/06/0612:17 pm08/06/0612:17 pm
Since the numbers are so succeptable to personal interpretation, and valve clearance, my cam data is off the base circle/pushrods. You still need to do the cam lift math with the rocker ratios of 1.13:1 then subtract the clearance. Method of data taking may be why the combat specs are are so far off from what you expect based on published factory data. http://atlanticgreen.com/camsurvey.htm
I don't have much faith at all on the NOC published data.....They state some of the data is from the NOC internet forum
dynodave BSA 3 1961-1963 Ducati 3 1992-2002 Norton many 1951-1975 87 Serv-Equip 100HP MC brake dynamometer,
Re: Norton Racing camfollowers#65884 08/06/0610:00 pm08/06/0610:00 pm
The 380 " number was measured by myself off the base circle/pushrod. I guarantee it is correct to within 2 thou. I sent the data to Dynodave about three years ago to add to the others on his site. Dave and I corresponded on the methodology and I therefore believe it is precisely comparable to the other data he has plotted there.
Dave - please correct me if I am wrong but I believe the PW3 Mike Hemmings supplied cam on your website are the figures I measured and sent to you a few years ago.
Im aware of the difference in "standards" in recording and publishing cam opening and closing figures(the 50 thou you mention- the primary purpose of which is to elimate measuring issues with quietening curves and difficulties in precise measurement on the very gradual start to the cam lobe etc).
However I have not seen any examples where this 50 thou "standard" is used for the cam lift. Usually the differences here are, as Dave says, due to tappet clearances and rocker ratios.
In any event I consider Dave's site to have the most reliable consitantly measured set of cam figures I have seen published. The PW3 figures there are exactly consistant with my measurements.
The PW3 has a lower lift than 3 or 4 of the other cams on Daves site but generally it sits toward the upper end of available profiles.
Re: Norton Racing camfollowers#65885 08/06/0611:01 pm08/06/0611:01 pm
As a comment, please note that all the data mentioned above is taken directly from the lobe, so it represents the exact motion the tappet will follow. It is quite possible that a diagram made by plotting actual valve lift measurements vs. crank rotation in a specific engine will not be a pantograph 113% height-distorted replica of the lobe plot. The motion "seen" by the tappet is only transmitted faithfully across the rocker arm to the valve stem when the rocker arm dimensions and geometry are perfect. If both the pushrod end and valve end of the rocker are not at 50% lift when the rocker axes cross the pushrod and stem (respectively) the motion will be distorted and lift reduced. If you plot your own engine and get errors, some diagnosis may be possible based on the math, let me know.
Re: Norton Racing camfollowers#65886 08/06/0611:38 pm08/06/0611:38 pm
"I don't think it is worth debating the origins of the PW3 grind. Each side has it's own story they will swear by, they will not give an inch so that it the end of it. I would ask PW or NW if the Norton team ever bought C.R. Axtell cams in the early seventies that might have been laying around for "inspiration", if they will not even "remember" this fact, then anything further is a waste of time right? "
In my post I asked if you had the figures for the Axtell#3 grind.
I freely acknowledged I did not have the data on the Axtell grind but I do have the data for the PW3 - measured by myself.
- and you are absolutly right - We do not have to debate this issue.
If you have the facts (ie the measured figures for the Axtell#3 grind) then state them and let the facts speak for themselves.
If the numbers plot up the same then you have a good case. If they don't then you don't have hard data to back up your assertion.
I note you have edited your original post and removed the bit where you said Peter Williams copied the Axtell cam.
As I said I have met Peter and he is one of the nicest guys you could imagine. His main aim in designing this cam was to control the valve train dynamics and provide a reliable cam for long distance road racing. A very different objective from American short track racing. The opening, closing and lift figures of any cam is only 1/10,000 of the work to properly design a cam. See http://www.designofmachinery.com/CDH/ Peter did this work.
I think that if you are to say he took data from another famous tuner then you should have the hard data to back it up.
You state that the Norton team " will not even "remember" this fact, ".
Who says this is a fact? What data can you supply to back it up?
But it is easy to prove or disprove your statement. A copy of the PW3 profile is up on Dynodaves website for all to see.
Please supply the data for an Axtel#3 so we can compare. Presumably you had some hard data on which to base your statement.
Re: Norton Racing camfollowers#65887 08/07/062:29 am08/07/062:29 am
Originally posted by johnm: Dave - please correct me if I am wrong but I believe the PW3 Mike Hemmings supplied cam on your website are the figures I measured and sent to you a few years ago.
John I'm sure I still have your data in my XLS.files....thanks again .... I would have to research to find out for sure which data set I used for my plot, but I will gladly post you with the credit. I had also done a plot off a friends commando core "Mick Hemmigs PW3", thereby getting the hardness measurement while it was in my grubby hands, in about May of 2002. http://atlanticgreen.com/hscam.htm
I think the data you had up about a year ago was my plot. (I recognised the data label nomclature) but I see you have updated your site this year and are maybe using other data now. Anyway I have looked at it and the figure looks fine. Please feel free to use the data I sent however you wish.
Have a good summer. Lots of rain down here !!
Re: Norton Racing camfollowers#65889 08/09/063:21 pm08/09/063:21 pm
Has anyone heard of an Accusump? It was used in drag racing. It was a cylinder with a piston. Oil on one side and air pressure on the other. Before starting the engine a valve was opened and the pressurized oil would pre-lube the engine for start up. Before the engine is shut off the valve is closed to keep the oil pressurized for the next start up.
If it was easy, everybody would do it!
Re: Norton Racing camfollowers#65890 08/09/065:01 pm08/09/065:01 pm
Yes, used one, works well, but: 1. huge 2. expensive If you're going to do something manually every time you start the bike why not make it easier, smaller, lighter, cheaper, and retro the pre-1936 H-D manual pump? Bolt a primer pump anywhere to the chassis where you can reach it, suction line is patched into the feed line as a source, discharge end with a check valve that unseats under mild pressure to prevent sumping goes to pushrod tube, tappet block, oil pressure switch, wherever you're most anxious or to a manifold with multi distribution points.
Re: Norton Racing camfollowers#65891 08/10/064:32 am08/10/064:32 am
Yeah, Yeah, Yeah, CR Axtell, CR Smaxtell, Axtell, from my memory, was mostly from the BSA, Triumph and the HD race crowd specializing in cylinder head flow, piston design, etc. on these machines only. Exactly how much time and $$$$ did he spend on Norton Engines and cam shaft R & D??? Not as much as others I am willing to guess, to note; Norman White's Commando 12.24 1/4 mile run at the Orange County raceway using a PW Cam.
Re: Norton Racing camfollowers#65892 08/14/0612:28 am08/14/0612:28 am
Please dont think I was wanting to say anything bad about C R Axtell in my question about his cam.
He reportedly obtained more peak hp out of his machines than the factory Nortons but since he was designing for American flat track racing and the Norton team were doing long distance road racing it seems very unlikely their engine development would end up in the same place.
I know almost nothing about Axtell but he clearly was extremely good.
My posting above was a bit strong maybe but it came from knowing Peter as a real gentleman and knowing he damn near gave his life racing Nortons. - and don't think the factory did him any favours after his crash. He had to take them to court to get the money he was owed.
Re: Norton Racing camfollowers#65893 08/16/069:52 pm08/16/069:52 pm
Axtell Shmaxtell? when Norton got serious about racing in the USA they contracted David Aldana as a rider and Nick Deligiannis at Axtell's as mechanic and C.R. Axtell and Mike Libby to do the development work. Axtell developed porting, cams, ignition and megaphones (look at the Axtell megs on the JP team bikes) for a potent 80+ horsepower package David won the Ascot TT national and Jorgenson on Wood's bike won the Ascot 1/2 mile national Axtell developed one of the fastest BSA goldstars ever, Gene Romeros championship winning Triumphs, the only championship race winning dirttrack Nortons, and did much of the development work on Mike Kidd's Lawwill championship XR750, Kenny roberts turned to him to build his comeback TT500 Yamaha the man does not need anyone to defend his reputation...his accomplishments speak for themselves anyone who would say Axtell Shmaxtell only exposes his own jealousy or ignorance...but then we don't know about your motorsports accomplishments...so please share them with us?
Re: Norton Racing camfollowers#65894 08/29/075:36 pm08/29/075:36 pm
I sent graphs of the Axtel #3 to Dave - maybe he has made comparisons to PW.
The stock lifters are way too heavy and cause valve float. My valves were banging on the pistons with the proper cleararce, all the valve train lightened and using racing springs. The way to go is with the BSA lifters & adapters - then choose a cam lobe lift and lobe duration to match what you are familiar with compared to flat tappet cams.
Re using BSA lighter followers. For racing around trying and often succeeding in blowing up motors at 7000 rpm plus using std cranks etc yes OK but for road use???? Has anyone compared the wiping surface area and pressures...remembering what cam profiles they were originally designed for. Strikes my tiny brain that higher lift and fiercer timing simply equals reduced life unless the whole lot is redesigned correctly.. at Norton Just because you see a race bike appear on consecutive weekends or meetings does NOT mean its the same olde highly tuned motor and things havent been changed in a mad rush during the week!!.....the barrels could well of failed at the base flange or the crank might have started to finally break at the stress raiser the twats left inside it but the rider felt the vibes start and shut off the motor thus it had just about stopped before the crank finally became a a 4 piece lump etc etc . Been there wotking feverishly during the week and got the T shirt. The reliable fast motors I knew had lowish CR and non high lift cams, just long dwell AND a tuned correctly designed exaust system. Better to finish the race riding the bike than watch everyone else ride to the finish.....Hell people have won World Championships not winning a race over the whole year. But do I care ?? Do I hell. When young I never listened and learnt from olde farts and merely made the same mistakes they did in their youth and now I is one why should anyone listen to me now????
Re: Norton Racing camfollowers#65898 08/31/075:53 pm08/31/075:53 pm
Yeah - you can blow them up. But They can take a lot and you can prevent the crank from breaking at the PTO shaft by cutting a radius into the cheek. This is tricky - takes a formed 1/8" diameter cutting bit and you have to keep moving it around so it won't chatter. Then polish it with 1/8" brass wire in a die grinder & valve grinding compound (covered in my race manual). The cases need reinforcing too (heat shrink or weld on a 3/8" plate).
And you're right about long cam durations. Pointy high lift cams cause more valve float.
The wear is much reduced with BSA lifters and its not because of the reduced weight. A flat lifter cam gets beat up in a couple seasons but a BSA radius cam still looks like new. The cams look completely different and the BSA lobed cams have a broad radius at the peak and the stress points must be spread around in a completly different manner.
The Norvil tappet blocks are probably Ok - but if you want to make your own I can fax you some plans.
Sure- you can get by with the standard lifters - we all do, but there is a better way.
You can compare the BSA to Norton lobe lifts (at .040" lift),& durations in the megacycle catalogue, at the Johnson cams website (custom cams at reasonable cost). You'll want to pay attention to lobe splits etc to avoid valve clash - stay close to familiar profiles.