Performance Camshafts for the Triumph TR6

The following table is a list of cams that are available on the open market today. I've attempted to list all available specifications. There is not a lot of call for TR6 cams these days, and so they have been removed from their web-sites. However, if you called, eg, Isky, and asked them, all that information is still in their books. This is a living document and will be updated as the information comes to hand.

The following cams listed here is not an endorsement for any of the cams. It is intended as a starting point for the engine-builder to help decide upon a choice of cam for their needs.

For an article on interpreting two of the most critical specifications (duration and lobe center angle), with simulations showing the effects of changes in these specs, click here.

  

Lobe Lift Valve lift @ 1.46:1 Valve lift @ 1.55:1 Advertized Duration (I/E)

 Duration @ 0.050"
Intake open (BBDC) Intake close (ATDC) Exhaust open (BTDC) Exhaust close (ABDC) Lobe Center Angle RPM Notes
Stock PI (UK) 0.25 0.365 0.388 280   35 65 65 35 105 1969-1971
PI (UK) 0.24 0.350 0.372 256   18 58 58 18 110 Post 1971
Carb (USA)

0.22
0.321 0.341 240   10 50 50 10 110 Early TR6/GT6
Carb (USA) 0.24 0.350 0.372 256   18 58 58 18 110 2000-5000 Post 1972
 
Ted Schumacher (TSI)
S2 0.279 0.407 0.432 282   31 71 71 31 110 3500-6000 Good for street
S4 0.283 0.413 0.439 293   42 71 71 42 104.5 4200-6500 Marginal for street
TSI275-6 0.293 0.428 0.454 275   3000-6500 Flat power curve
 
PRI (Performance Research Industries)
Stage 2 0.297 0.434 0.460 282  
 
Ken Gillander (British Frame and Engine) Profile #149 0.274 0.400 0.425 282   110 Good street racer, slight lope @ 800rpm
Profile #150 0.274 0.400 0.425 292   110 Unsteady idle
Profile #300 0.342 0.499 0.530 300   45 77 85 37 109 JK Jackson cam, too much with roller rockers
 
American Cams M-26 0.31 0.453 0.4805 290   35 75 75 35 105 Very aggressive for street
 
TriumphTune
Road 83 0.288 0.420 0.446 266   30 56 74 28 104 2200-5200 max bhp @ 4750
Fast Road 83 0.288 0.420 0.446 280   37 63 74 28 107.5 2500-6000 max bhp @ 5250
Fast Road 0.270 0.394 0.419 280   30 70 70 30 110 2500-5500 max bhp @ 5500
Fast Road 89 0.293 0.428 0.454 290   34 76 58 34 106 2750-6250 max bhp @ 5750
Sprint 83 0.275 0.401 0.426 288   34 74 74 34 110 2700-5750 max bhp @ 5750
Sprint 0.274 0.400 0.425 288   38 70 70 38 106 3000-6500 max bhp @ 5750
Race 0.280 0.409 0.434 302   42 80 74 48 106 3500-6500 max bhp @ 6000
Race 83 0.302 0.441 0.468 290   42 68 78 32 108 3300-6500 max bhp @ 6000
Race 86 0.29 0.423 0.450 320   54 86 86 54 106 3400-7000 max bhp @ 6250
 
Richard Good (GoodParts)
GP2 0.258 0.377 0.400 278   2000-5500 No lope at idle
GP3 0.282 0.412 0.437 288   2500-6000 Nice lope @ idle
 
 
Isky
Z-19 0.274 0.400 0.425 268   24 64 64 24 110 Road/race, regrind only
Z-66+10 0.309 0.451 0.479 282   31 71 71 31 110 Competition, regrind only
 
Kent Cams TH2-6 0.261 0.381 0.405 295   39 76 76 39 108 2500-6500 Sports "R", valve lash (I/E) 0.022/0.024
  TH5-6 

 0.281
 0.423  

 280
 

 37

 63

 73

 27
 103

2200-7000
Sports "R", valve lash (I/E) 0.022/0.024
 

 TH6-6

 0.309
 0.447  

 290
 

 42

 68

 78

 32
 103

 3000-7500
Supersport, valve lash (I/E) 0.022/0.024
 

 TH7-6

 0.324
 0.470  

 300
 

 47

 73

 83

 37
 103

 3750-8000
Race, valve lash (I/E) 0.022/0.024
                           
Crower
 
 
Crane  
 
Web Cams #84  0.273 0.398 0.423 248 214              Good alround cam, broad power, for stock engines
   #7 0.288 0.420 0.446 260 232              Improved mid-range and top-end for hot streetb engines
   #1 0.298 0.435 0.462 290 252              Strong mid-range and top-end for racing engines
                           
Elgin Cams TR250  0.214 0.312 0.347 233 193              Stock replacement for TR250, very early TR6
   TR2 0.238/0.248     240/246 188/209              TR2 profile for TR6
  TR6  0.244/0.241     246/245 209/204              Stock replacement for late TR6
   64.5-12 0.251 0.366 0.389 258 204              Street performance
   TR3/TR4  0.262 0.383 0.406 264 217              TR3/TR4 profile for TR6, street performance
   TR5 0.255 0.372 0.395 269 226              Stock replacement for TR5
   67-18 0.289 0.422 0.448 268 222              Performance street, 9:1, springs
 70-9 0.262 0.383 0.406 280 228              Hot street, 9.5:1, max cam w/o bearings
   715-18 0.305 0.445 0.473 286 245              Hot street, headers, 10:1
 75-12 0.300 0.438 0.465 300 250              Full race, 12:1, head work
   77-9 0.312 0.455 0.484 308 256            5000+  Road race
                           
 APT Camshafts  TR26  0.256 0.374 0.397 278              2000-6000  Performance
   TR56 0.290 0.423 0.450 276              2500-6800 Hot street
   TR66  0.308 0.450 0.477 284              3200-7700 Vintage race
 TR76 0.324 0.473 0.502  295              3800-8000  Full race

Notes:

# Stock lift ratio on US (carb) cars is 1.46:1, and UK (PI) is 1.50:1.

Valve lift is given assuming stock US rockers (1.46:1) and 1.55:1 roller rockers.

Lobe center angle has been calculated, as it is generally not given. To do this, it is assumed that the lobes are symmetrical. Modern cams are often assymetrical, but it is likley that older grinds for the TR6 are probably symmetrical. Many thanks to Vance Navarrette of the 6-Pack mailing list for computing these numbers! To understand the importance of this critical (but rarely given) specification, click here.

Observations:

Notice how the British do not give any details on the cam grind, but rather use evocative name for description.

Finally, the specifications here are sadly incomplete. Information such as cam lift at various angles of rotation are necessary to determine the rates of acceleration on the leading and trailing flanks of the profile, lobe center angle, timing points at 0.050" rise off the base circle, etc. Cam profiles are perhaps the most complex part of a motor, and often this information is jealously guarded!


Back to my Triumph TR6 page

Last update: 27 December 2002.