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 |
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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 |
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3000-6500 |
Flat power curve |
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PRI (Performance Research Industries)
|
Stage
2 |
0.297 |
0.434 |
0.460 |
282 |
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Ken Gillander
(British Frame and Engine) |
Profile
#149 |
0.274 |
0.400 |
0.425 |
282 |
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110 |
|
Good street
racer, slight lope @ 800rpm |
|
Profile
#150 |
0.274 |
0.400 |
0.425 |
292 |
|
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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 |
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American Cams |
M-26 |
0.31 |
0.453 |
0.4805 |
290 |
|
35 |
75 |
75 |
35 |
105 |
|
Very aggressive
for street |
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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 |
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Richard Good (GoodParts)
|
GP2 |
0.258 |
0.377 |
0.400 |
278 |
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2000-5500 |
No lope at idle |
|
GP3 |
0.282 |
0.412 |
0.437 |
288 |
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2500-6000 |
Nice lope @ idle |
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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 |
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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 |
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Crower
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Crane |
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Web
Cams |
#84 |
0.273 |
0.398 |
0.423 |
248 |
214 |
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Good alround
cam, broad power, for stock engines |
|
#7 |
0.288 |
0.420 |
0.446 |
260 |
232 |
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Improved mid-range and
top-end for hot streetb engines |
|
#1 |
0.298 |
0.435 |
0.462 |
290 |
252 |
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Strong mid-range and top-end
for racing engines |
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Elgin
Cams |
TR250 |
0.214 |
0.312 |
0.347 |
233 |
193 |
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Stock replacement
for TR250, very early TR6 |
|
TR2 |
0.238/0.248 |
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240/246 |
188/209 |
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TR2 profile for TR6 |
|
TR6 |
0.244/0.241 |
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246/245 |
209/204 |
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Stock replacement
for late TR6 |
|
64.5-12 |
0.251 |
0.366 |
0.389 |
258 |
204 |
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Street performance |
|
TR3/TR4 |
0.262 |
0.383 |
0.406 |
264 |
217 |
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TR3/TR4 profile for TR6,
street performance |
|
TR5 |
0.255 |
0.372 |
0.395 |
269 |
226 |
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Stock replacement for
TR5 |
|
67-18 |
0.289 |
0.422 |
0.448 |
268 |
222 |
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Performance street, 9:1,
springs |
|
70-9 |
0.262 |
0.383 |
0.406 |
280 |
228 |
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Hot street,
9.5:1, max cam w/o bearings |
|
715-18 |
0.305 |
0.445 |
0.473 |
286 |
245 |
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Hot street,
headers, 10:1 |
|
75-12 |
0.300 |
0.438 |
0.465 |
300 |
250 |
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Full race,
12:1, head work |
|
77-9 |
0.312 |
0.455 |
0.484 |
308 |
256 |
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5000+ |
Road race |
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APT
Camshafts |
TR26 |
0.256 |
0.374 |
0.397 |
278 |
|
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|
2000-6000 |
Performance |
|
TR56 |
0.290 |
0.423 |
0.450 |
276 |
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2500-6800 |
Hot street |
|
TR66 |
0.308 |
0.450 |
0.477 |
284 |
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3200-7700 |
Vintage race |
|
TR76 |
0.324 |
0.473 |
0.502 |
295 |
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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.