Triumph Spitfire camshaft data Software: Microsoft Office
Software: Microsoft Office
from: Paul Geithner's Triumph Spitfire Links, References and Technical Information
(see explanatory notes below)
compiled by Paul Geithner on the web at: http://auskellian.com/paul/links_files/spitfire_cam_specs.htm
[email]
intake             exhaust            
rocker ratio = 1.46 rocker ratio = 1.46
manufacturer camshaft model BTDC
open		 ABDC
close		 duration cam
lift		 clearance valve
lift		 lobe peak
(ATDC)		 BBDC
open		 ATDC
close		 duration cam
lift		 clearance valve
lift		 lobe peak
(BTDC)		 overlap lobe
angle		 manufacturer's notes (RPM range is advertised power band)
Triumph (stock factory) 1147cc (mk1) 18 58 256 0.215 0.010 0.304 110 58 18 256 0.215 0.010 0.304 110 36 220 small journal, uses cam bearings
[from Haynes manual] 1147cc (mk2) 25 65 270 0.215 0.010 0.304 110 65 25 270 0.215 0.010 0.304 110 50 220 "
" 1296cc (low & high CR) 25 65 270 0.240 0.010 0.340 110 65 25 270 0.240 0.010 0.340 110 50 220 ", considered 'best' of the stock cams
" 1296cc (emission controlled) 10 50 240 0.220 0.010 0.311 110 50 10 240 0.220 0.010 0.311 110 20 220 large journal, no cam bearings
" 1493cc 18 58 256 0.240 0.010 0.340 110 58 18 256 0.240 0.010 0.340 110 36 220 "
Triumph Tune (Moss U.K.) road 83 30 56 266 0.288 0.016 0.404 103 74 28 282 0.288 0.016 0.404 113 58 216 mild profile for everyday use; 2200-5200, peak hp @ 4750
" fast road 83 37 63 280 0.288 0.022 0.398 103 74 28 282 0.288 0.024 0.396 113 65 216 very good all-around cam for fast road and traffic conditions; 2500-5500, peak hp @ 5250
" fast road 89 36 74 290 0.293 0.014 0.414 106 58 34 272 0.293 0.014 0.414 102 70 208 very good cam w/ more lift than f/r 83, better mid-range and top-end power; 2750-6250, peak hp @ 5750
" sprint 38 70 290 0.274 0.014 0.386 105 70 38 288 0.274 0.015 0.385 106 76 211 specifically designed for weekend sprint events, but still tractable for daily use
" sprint 90 39 71 290 0.302 0.014 0.427 110 81 29 290 0.302 0.015 0.426 116 68 226 tractable cam w/ very good mid- to top-end power; fuel injected only
" race 83 42 68 290 0.302 0.022 0.419 103 78 32 290 0.302 0.024 0.417 113 74 216 circuit car only, desinged for max top end power
" race 86 51 79 310 0.290 0.018 0.405 104 79 51 310 0.290 0.022 0.401 104 102 208 circuit car only, designed for max top end power
Kent Cams TH12 31 59 270 0.287 0.016 0.420 104 67 23 270 0.287 0.018 0.418 113 54 217 high torque; 1500-6500
" TH2 39 76 295 0.261 0.014 0.382 108 76 39 295 0.261 0.018 0.378 113 78 221 fast road; 2500-6500
" TH3 34 70 284 0.282 0.016 0.412 108 70 34 284 0.282 0.016 0.412 113 68 221 rally; 3750-6800
" TH5 37 63 280 0.293 0.022 0.423 103 73 27 280 0.293 0.024 0.421 113 64 216 fast road; 2200-7000
" TH6 42 68 290 0.308 0.022 0.447 103 78 32 290 0.308 0.024 0.445 113 64 216 rally; 3000-7500
" TH7 47 73 300 0.324 0.022 0.470 103 83 37 300 0.324 0.024 0.468 113 64 216 race; 3750-8000
Newman Cams TRIS/260/375 PH1 20 60 260 0.250 0.014 0.375 110 60 20 260 0.250 0.016 0.375 110 40 220 road; ideal road cam for town use, good idle; 1500-6000
" TRIS/280/405 PH2 30 70 280 0.270 0.014 0.405 110 70 30 280 0.270 0.016 0.405 110 60 220 fast road/rally; good mid-range power; 3000-6500
" TRIS/300/435 PH4 40 80 300 0.290 0.014 0.435 110 80 40 300 0.290 0.016 0.435 110 80 220 race; powerful mid-range race cam; 4000-8000
Piper Cams TRBP255 17 55 252 0.275 0.022 0.380 109 55 17 252 0.277 0.024 0.380 113 34 222 mild road; 1500-5800
" TRBP270 26 62 268 0.292 0.012 0.414 108 62 26 268 0.292 0.014 0.412 113 52 221 fast road; 2000-6400
" TRBP285 36 68 284 0.292 0.012 0.414 106 68 36 284 0.293 0.014 0.414 113 72 219 ultimate road; 2800-6800
" TRBP300 44 76 300 0.317 0.018 0.445 106 76 44 300 0.317 0.018 0.445 113 88 219 race; 3500-7500
SpitBits "fast road profile" fast road; 2000-6500. Latest asymmetrical design profile using short duration opening, long duration
British Parts Northwest "BP270" closing inlet with long duration opening, short duration closing exhaust. Standard valve springs may
actually Piper HR270/2 22 70 272 0.292 0.012 0.415 112 62 28 270 0.284 0.014 0.400 106 50 218 be used. Up to 10 bhp can be gained with excellent bottom end and mid range power.
Isky Cams HR-8-003 13 53 250 0.252 0.012 0.356 112 53 13 250 0.252 0.012 0.356 108 26 220 stock refinish
" E4-58A 20 60 260 0.268 0.016 0.375 110 60 20 260 0.268 0.016 0.375 110 40 220 combination
" ZM-66 24 64 268 0.307 0.018 0.430 110 64 24 268 0.307 0.018 0.430 110 48 220 competition
" ZM-66-10 29 69 278 0.307 0.018 0.430 110 69 29 278 0.307 0.018 0.430 110 58 220 competition
" Z-307 40 80 300 0.348 0.028 0.480 110 80 40 300 0.348 0.028 0.480 110 80 220 super competition
Elgin Cams 64510-12 258 0.252 0.011 0.357 258 0.252 0.013 0.355 performance 1147, 1296 large tappet engines
" 6610-15 264 0.262 0.013 0.370 264 0.262 0.015 0.368 2 steps up, compression needs to be raised
" 7010-9 280 0.263 0.010 0.374 280 0.263 0.012 0.372 hot street; 9.5:1, springs, header
" 71508-18 286 0.305 0.019 0.426 286 0.305 0.021 0.424 autocross/race; 10:1, good head
" 7508-12 300 0.323 0.014 0.458 300 0.323 0.016 0.456 autocross/race; 11:1
" M7708-13 308 0.321 0.014 0.455 308 0.321 0.016 0.453 road race; 12:1, 5000-7500, must dyno tune
" 7708-12 308 0.348 0.016 0.492 308 0.348 0.018 0.490 road race; 5500-7500, must dyno tune
" 7806-14 312 0.328 0.017 0.462 312 0.328 0.019 0.460 GT3; 13:1
TSI Automotive B 30 70 280 0.290 0.014 0.409 110 70 30 280 0.290 0.014 0.409 110 60 220 Kastner/comp prep manual profile; good mid-range; 3500-6000
" TSI275-4 28 67 275 0.303 0.018 0.425 110 67 28 275 0.305 0.020 0.425 109.5 56 219.5 flat power curve; 3000-6500
" A-6 288 0.280 0.018 0.391 288 0.282 0.020 0.391 Kastner/comp prep manual profile; marginal for street; 4000-7000
" A-8 290 0.332 0.020 0.465 290 0.334 0.022 0.465 Kastner/comp prep manual profile; race only; 4500-7500
" TSI298-4 298 0.347 0.022 0.485 298 0.349 0.024 0.485 race only; 4500-8000
APT TH24 278 0.256 0.016 0.358 278 0.256 0.018 0.356 TR 1300/1500 performance; 9.0-9.5:1; 2000-6000; peak hp @ 6500
" TH54 276 0.290 0.022 0.401 276 0.290 0.024 0.399 TR 1300/1500 hot street; 9.0-9.5:1; 2500-6800; peak hp @ 7200
" TH64 284 0.308 0.022 0.428 284 0.308 0.024 0.426 TR 1300/1500 vintage race; 11-12.4:1; 3200-7700; peak hp @ 8200
" TH74 295 0.324 0.022 0.451 295 0.324 0.024 0.449 TR 1300/1500 full race; 11.5-13:1; 3800-8000; peak hp @ 8400
Integral Cams Stage 1 265 0.280 0.012 0.397 265 0.280 0.014 0.395
" Stage 2 272 0.295 0.016 0.415 272 0.295 0.018 0.413
" Stage 3 280 0.310 0.018 0.435 280 0.310 0.020 0.433
" Stage 4 290 0.325 0.020 0.455 290 0.325 0.022 0.453
" Stage 5 296 0.340 0.020 0.476 296 0.340 0.022 0.474
" Stage 5 Aggressive 296 0.340 0.020 0.476 296 0.340 0.022 0.474
" N7 Race 301 0.335 0.022 0.467 301 0.335 0.024 0.465
" Stage 6 304 0.343 0.022 0.479 304 0.343 0.024 0.477
NOTES:
values in BLUE = manufacturer's quoted values or measured values
values in italics = quoted values different than calculated results (quoted values shown)
values in BLACK = calculated (see equations below)
values in GREY = guesses, unverified data or calcs based on such
BLANK = no data or insufficient data to calculate
duration = opening+closing+180
valve lift = cam lift*rocker ratio - clearance
cam lift = (valve lift + clearance)/rocker ratio
lobe centers (for symmetrical lobes only):
intake lobe center ATDC = 0.5*duration - in. opening BTDC
exhaust lobe center BTDC = 180-(0.5*duration - ex. opening BBDC)
lobe angle (in crank degrees) = ex. lobe center BTDC + in. lobe center ATDC
overlap = intake opening BTDC + exhaust closing ATDC
ROUGH guides:
more lift: some additional power
longer duration higher peak power at higher RPM
(for a given lobe angle): power band widens and moves up
less torque at low RPMs
higher fuel consumption and emissions
rougher idle
more overlap a/o more peak power
tighter lobe separation power band narrows and moves down
(for a given duration): more torque at lower RPMs
higher fuel consumption and emissions
rougher idle
advanced timing: power peak shifts to lower RPM
(for a given lobe angle slightly reduced peak power
and duration): slightly increased low-end torque