Following are links to a variety of Norton heavy twin cam profiles.
They represent many, many, hours of data taking of a sampling of Norton
factory, Axtell, Dunstall, Harmon & Collins, Johnson, Megacycle, Norris,
Norvil, Pete Williams(Hemmings) and Web.
The newer profiles have been taken on the new cam measuring test fixture
I designed and fabricated. Measurements are to .0001" resolution. The main
limitation is my seeing and then setting the degree wheel by hand. This
degree of resolution shows the variations within the base circle of some
cams and brings into question the capability to accurately set valve lash.
Pix of cam measurement fixture
All the profile data is raw cam lift data measured directly off the
cam with a flat or 3"radiused brass shoe, and no rocker arm ratio or clearances
are taken into account.
Unfortunately during my early profiling, I did not pay as much attention
to detail in the opening and closing ramp areas. On those, only the lift
and overlap are useful. The later ones show more detail. I will be going
back over the cams I still have access to, and retake the profile data
with the extra detail needed. As of this date many are completed, but some
cams I do not have access to, and are not likely to be reaccomplished.
NHT cams are either on twin chain (cam/magneto) core or later commando
single cam drive chain version.While they have some dimensional similarities,
they are not interchangeable.
Norton
cam100.gif
D12-790 The original 29hp dominator model 7 cam, very mild. It is installed
a little more advanced than shown on the graph. This engine comes standard
with radiused lifters.
cam140.gif
21225 This is from a standard model 88. Significantly hotter than the model
7 cam.
cam110.gif
22729, 650SS and later 750 Atlas grind with common X2
marking on the twin chain core, know as SS
cam110a.gif 061084
This cam grind started as the 650ss cam shown above, by now it's called
the 1S for the commando, it is the standard cam grind for all non combat
750 and 850 comandos. Lobe centers are 100º
cam120.gif
063536 The famous or "infamous" 2S combat cam. Note*** this is MARKED
"SS" on the camshaft, but it is not the 650SS (1S) grind.
cam120a.gif 2S
Combat grind with 3" radius lifters.
Dunstall
cam210.gif
PD04ZC mild cam not much hotter that a stock cam. A bit more lift and duration, very little extra overlap.
Used in my Dunstall Atlas on a twin chain core and This is the same Dunstall grind later supplied for commando's on a single chain core.
cam220.gif
PD R2 B540 WFC, This cam was out of a grenaded 810 Dunstall kit,
probably the claimed 75HP version when ALL the mods have been done, including
the ported reangled big valve intake head.. The cam I sampled was prepped
for needle roller bearings and pressure oil feed to the cam lobes.
Similar grind to the Norton Combat 2S cam.
cam230.gif
PD/03 E434 WEC, 20M3 core,profiledwith flat and 3" radius lifter, LC 105º,
exh .333", int .346", loan by Tom Patterson
Axtell
cam350.gif
Axtell 5S data courtesy of David Winship. Like a stock cam only with about
5% more lift. But a fair amount more duration (40º)
Norvil
cam430.gif
3S camshaft. Very close to 2S Combat, Hard to tell any difference.Thanks to Brian Finck, Ontario Canada
cam440.gif
4S camshaft. Also very close to 2S Combat when the extra lash clearance is taken into account!
cam470.gif
7S camshaft. Getting warm yet?.
Megacycle including their Norris profiles
Caution-Megacycle uses a 1/4-28 bolt to retain
ignition AA unit or ignition rotor. vs 1/4-26bsf on english commando 20M3S+
cams.
cam510.gif
Norris RX data with thanks to John Magyar, a bit more overlap than PW3
cam520.gif
Norris D
cam630.gif
56-0NR This would be the cam I would recommend as the slight boost over a regular norton 06-1084 1S cam without the "hot rod" syndrome.
cam640.gif
56N480
cam610a.gif
56-000/11-01 EOB with both flat and 3" radiused lifters
cam620a.gif
56-020 with both flat and 3"radius lifters
Johnson
cam920.gif
NT360
Web
cam931.gif
Web 132 a good cam for an 850, not to hot...similar to a megacycle 5600NR-Thanks for loan Bob Bolduc NENO member
cam932.gif
Web 86C/12C a touch hotter than 4S
Pete Williams
cam940.gif
Hemmings supplied PW3 grind-loan by Mike Pappas
Harmon & Collins
cam910.gif
7014 drag race? Viscious lift rate off the ramp!!!-loan by Sherwood
Shute
cam911.gif
7138 A bit more exhaust lift and similar overlap to the PD04CZ-loan bySherwood
Shute
cam912.gif
H&C?? 168 extracted from a twin chain 650 as it was not a good choice for a street motor
Comparisons
cam101411.jpg
M7, 88, 650SS(1S)
cam1121.gif
1S cam, Dunstall 04ZC cam
cam2123.gif
PD03-105º, PD04ZC-102.3º, virtually same profile with different
lobe centers.
cam111244.gif
1S, 2S and 4S cams
cam432.gif
2S, 3S
cam247.gif
2S, 4S, 7S
cam356392.gif
5S, NR, NT360 virtual clones....Who made who?
cam936247.gif
Web8612, 56-020, 7S
cam9961.gif
Larry Martin's hot rod cam, megacycle 56000 3" radiused lifters
MISC extra profiles
cam950.gif
A 1970's grind by englishman Lloyd Dickensen, a bit more overlap than the
PD04CZ-loan by Roddy MacLellan
cam120rw.gif
2S on a domi core. This shows a lot of detail on the exhaust ramp and a
second set of ramp profiles super imposed on the original profile. This
second set of ramps it the "after" of the grinding process that I did to
the cam to make it suitable for my purposes. Pix
of cam measurement and grinding process Norvil sourced, but they
claim Norton Andover are supplying them. It has been verified by two others
that a 4S (domi and commando core ) and the 2S (commando core) are also
afflicted with this design ramps. Care should be used to insure enough
valve lash on these cams.
