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triumph cams

23K views 29 replies 17 participants last post by  Mr.Pete 
#1 ·
what are the e2478 cams? are the they stock pre unit cams?
Thanks,
Travis
 
#8 ·
this list here, was posted by john healy (i believe) on the BB forum. your cam isn't on it, and i was under the impression that this list was pretty complete.

Group 1 - High Performance - E3134 "Q" Cam Form
Part # Code Casting # Timing Detail
E3134 E3134 I0 34° BTDC - IC 55° ABDC - EO 55° BBDC - EC 34° ATDC Inlet or exhaust
E4819 X E3134 " " " " Inlet 5047 YCP E5048 " " " " Exhaust E5162 XCP E4602 " " " " Inlet
E10040 XN E10040 " " " " Inlet
E10041 YN E10041 " " " " Exhaust
E4038 SG E3838 " " " " Inlet
E4039 E3838 " " " " Exhaust
E4678 E4679 " " " " Inlet
E5044 YCP E5045 " " " " Exhaust
E5047 Y* " " " " Exhaust
E5163 CP E4679 " " " " Inlet
E6965 Y E6642 " " " " Exhaust
E10043 N E10043 " " " " Inlet
El 0047 E10050 " " " " Exhaust
E11063 N 71-0040 " " " " Inlet
E11064 N 71-0043 " " " " Inlet
E9983 YN 70-9986 " " " " Exhaust
E9984 YN 70-9987 " " " " Exhaust
E9989 YN 70-9990 " " " " Exhaust
Note: 1. Running clearance .002 in. intake and .004" exhaust.
2. Take readings at .020 in. follower lift with "std" radius (3/4 in.) followers
3.
<st1:place><st1:placeName>Lobe</st1:placeName><st1:placeType>Center</st1:placeType></st1:place> 100.5°
4. Duration 269 °
5. Lift .314 in.
Group 2 - High speed touring - E3325 Cam Form
E3325 E3325 IO 27° BTDC - IC 48° ABDC - EO 48° - BBDC - EC 27 ATDC Inlet or Exhaust
E4818 X E4997 " " " " Inlet
E4848 Y E4560 " " " " Exhaust
E4855 Y E4561 " " " " Exhaust
E4931 " " " " Inlet
E4022 SG E3838 " " " " Inlet
E4023 E4679 " " " " Exhaust
E4786 Y E4679 " " " " Exhaust
E10046 YN E10049 " " " " Exhaust
Note: 1. Running clearance .002 in. intake and .004" exhaust.
2. Take readings at .020" follower lift with "std" radius (3/4 in.) followers
3. Lobe center 100.5°
4. duration 255°
5. Lift .296 in.
Group 3 - Ramp cam form (standard) - Quieting ramps
E3275 E3265 IO 26.5° BTDC - IC 69.5° ABDC - EO 61.5° BBDC - EC 35.5° ATDC Inlet or Exhaust
E3838 SG E3838 " " " " Inlet
E3839 E3838 " " " " Exhaust
E5341 Y E5342 " " " " Exhaust
Note: 1. Running clearance .010 in Intake and Exhaust.
2. Take readings at .020" follower lift using "std" followers.
Group 4 - Modified ramp form (racing)
Thruxton Bonneville
E4220 E4220 Valve lift at TDC with nil clearance 0.195/0.175" Intake or Exhaust
E6267 E4220 Valve lift at TDC with nil clearance 0.205/0.215" Intake
E6147 Y E6146 Valve lift at TDC with nil clearance 0.165/0.175" Exhaust
Note: 1. Running clearance E4220 .008 in. E6267 & E6147 .013 in.
2. Valve timing taken in inches of VALVE lift at T.D.C. with valves set at nil clearance for checking.
3. E6267 and E6147 must be used with 3" radius cam followers and special guide blocks.

Key to Codes: X = Breather Y = Contact breaker n = nitrited CP = Copper plated SG = Spiral gear (distributor drive)
 
#9 · (Edited)
As the title fits, i'll resurrect this instead of starting a new one.

I'm combining a '67 T100T motor's internals (cracked cases etc) with the cases and crank off a '73. Digging out the cams gave E4678 stamped on the intake, exhaust is E5045.
Both can be found in the "Group 1 - High Performance - E3134 "Q" Cam Form" of 2_wheel_nation's post above.

Anybody know about cams for the unit T100's? I want to make sure it has some oomph, and I am going to be using dual 626's. The T100T had a single 930 fitted earlier. Are these cams worth using? T100C or T100T/R?

Any input appreciated.
 
#10 ·
Cam forging blank numbers
-------------------------
These are not cam numbers, they are the part number for a blank that a
cam profile is ground onto. A single blank will often be used for a
number of different cam grinds, so this number doesn't actually tell
you what cam you have. The forging number should have raised numbers,
the cam grind number should be stamped in. Either number is sometimes
omitted.
 
#11 ·
Not to take away from the current question in this thread, but I have an answer for the original question, in case anyone still cares:

E2478 is a race cam that pre-dates the E3134 profile. It was superceded by the E3134. I believe the E2478 is actually the exhaust cam from the set. This cam would have been used in the Grand Prix models, and very early T100 race kits.

-Shaggy
 
#12 ·
Well here's what I've dug up so far.

The E4678 intake is stock according to my '66 and '67 parts lists.

On Britbike i found this:
"E5045 is a 1966 exhaust cam with racing profile. Timing is the same as Daytona-type cams.
I dont think it is listed in a partsbook"

Guess I'll just use 'em and see.
 
#17 ·
Re: Triumph Pre unit cams or unit? in a Tr6r

The exhaust is correct for a 1970 650. If memory serves, the number doesn't exactly match what the parts book says, but that is the right one for the late 650 engines.

The intake is a pre-unit cam. No real difference between post-war preunit and unit intake cams, although I think by 1970 Triumph was using an E3134 intake profile, instead of the E3325 one for the intake. That intake cam is likely not nitrited, like the factory one would have been for 1970, although that just means it won't last as long.

-Shaggy

Just cracked my case, found this
Intake- marked E2478 MF A1 and also E3325
Exhaust- Marked 71-0042 and also 70-9990

So what should I believe they are?
And what are they
Cheers
VT
 
#15 ·
Well, I have nothing to offer in terms of any answers, but I do have questions.

My cams are marked as follows: Intake (71-0040 RW) Exhaust (71-0042 maybe'3')

Does the "71" indicate the model year? also, the liost on page 1 shows both of those being intakes. Can that be right?
 
#18 ·
Those are late 650 intake and exhaust cams. The intake and exhaust will differ on the units becuase the front of the exhaust cam will have the drive for the points.

The '71-' part is Triumph's translation of their part numbers when they went from letter to number prefixes. All engine parts started with E, as in E3134 for one of the cams. When Triumph went to numbers, that became a 70-3134. The problem that they ran into was the fact that they had run out of 4 digit numbers for the engine parts. So, the 5 digit part numbers went from E10040 to 71-0040 so that they all were two digit prefix and 4 digit suffix.

I have never seen a truly accurate list of all of Triumph's cams. This is in part, due to the fact that the part number on a cam was sometimes the part for the cam blank, sometimes the part number for the profile, and sometimes both. Triumph often changed the part number for the same profile, and often the numbers on the cams don't match what is in the parts book....although often they do :)

-Shaggy

Well, I have nothing to offer in terms of any answers, but I do have questions.

My cams are marked as follows: Intake (71-0040 RW) Exhaust (71-0042 maybe'3')

Does the "71" indicate the model year? also, the liost on page 1 shows both of those being intakes. Can that be right?
 
#21 ·
Here's a question for you guys: pulled my '53 6T cases apart for overhaul and the exhaust cam has a funny grind near the apex of the lobes.... sorry it's a little hard to see there are "flats" looks like someone ground by hand almost.... forging # is E3325 M/F A2, stamping is 3134. Intake profile is smooooth, no "flats". What do I have (besides a paperweight)? Thanks, Tombat





 
#22 ·
Hello Tombat, this one's for tossing at a stray dog! Triumph exhaust cams are notorious for wear, and they went to all kinds of lengths to fix it, from auxilliary cam follower oil feeds in the 60's, to copper plating, then in '69 to nitride hardening. I still see plenty of well worn nitrided cams as well - good lube, good valve springs (to reduce "bounce" at the cam) all help. If you want the same profile (E3134), I would go for the late Nitrided 70-9989 (E9989) cam. It has the extra gubbins for driving unit construction cams, but who cares in a pre-unit mill.
 
#23 ·
Thought I'd resurrect this thread since I was just looking at a set of Pre-Unit 500 TR5-T100 cases I have and the intake cam is cast E2478 and stamped E3134 coupled with an exhaust cam E3325.

Apparently, there are more than a few cast E2478 cams out there as Daddy Boy had pointed out in an earlier post but with different profiles. Anybody got any insight or observances to add to this?

Also, E2478N is listed as a T100 Race Kit exhaust cam but this cam has the hole drilled near the center that seems to be common to intake cams. Hmmm !
 
#24 ·
I got that info from Shentons tuning book and he was talking about 3134.
Quote "E3134 is a Triumph designation for a cam profile rather than an actual camshaft, and no less than 14 different cams, each with its own part no. have been offered with this profile. But what is more imortant is that the E3134 form can no longer be regarded as as a high performance cam design. They were not fitted as standard to the Bonneville and all other cams mentioned will give far better results for racing purposes."

He mentions the Thruxton cams (E4220) and the E 6987 IN/E6988 EX. "Which produce useful power between 3000-7000 rpm. These good torque production cams are in fact BSA Spitfire profiles on a Triumph shaft"

For the 500 Jon, he mentions the best standard cams for 500 engines are those fitted to Daytona models from eng no.H49833. (40,52,61,31.) The factory did produce a small no. of special cams (p/n IN E7670.EX E7671) which had the 650cc cam profile on the 500cc shaft."Very slight improvement and not widely available.
 
#27 ·
Interesting:
http://www.classic-british-motorcycles.com/1973-triumph-tr7.html
Scroll down to HOT CAMS.
Cams are definitely an interesting subject.You never hear feedback of over hot cams thrown in streetbikes, they'll blame the bad street performance on somethin else, not even good for passin cars.
When it boils down, only the tried and very experienced guys know how to make a motor work GOOD with a variety of modifications.
There's really nothin like a stock, well tuned engine to triumph specs for the street and country I reckon.
When you start fucking with big cams you then have to figure the math on carbs, exhaust, headwork, timing figures to suit etc etc etc!
Sometimes things are simple, like using an inlet profile(the right one) on the exhaust side of a 750 for straight up better performance. Triumph detuned the EX cam for whatever green reason.
 
#29 ·
Interesting:

Cams are definitely an interesting subject.You never hear feedback of over hot cams thrown in streetbikes, they'll blame the bad street performance on somethin else, not even good for passin cars.
When it boils down, only the tried and very experienced guys know how to make a motor work GOOD with a variety of modifications.
There's really nothin like a stock, well tuned engine to triumph specs for the street and country I reckon.
When you start fucking with big cams you then have to figure the math on carbs, exhaust, headwork, timing figures to suit etc etc etc!
Sometimes things are simple, like using an inlet profile(the right one) on the exhaust side of a 750 for straight up better performance. Triumph detuned the EX cam for whatever green reason.
Good call DB, sound advice. I doubt there's many riders of street Trumpets that would exploit the high RPM gains out of a lot of these wild profiles available nowadays anyway.
 
#28 ·
Johnson cams.Triumph T-75 Cam
Stock 750 twin intake. Use in exhaust also, for hot street motors- and racing, where endurance means more than the last HP. Good to 7000rpm with stock springs.
$360pr. Lift LCA Lash Tappet Duration Open Close At
Intake .345 105° .010 S 294°
270° 40°btdc
29°btdc 74°abdc
61°abdc .020
.040
Exhaust .345 105° .010 S 294°
270° 71°bbdc
59°bbdc 44°atdc
32°atdc .020
.040

Browny
 
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