GT-6, Spitfire & TR camshafts | |||||||||||||||
Camshafts from Standard Triumph & GTT (Good stuff in BOLD) | |||||||||||||||
Application | Part No | Inlet opens BTDC° | Inlet closes ABDC° | Exhaust opens BBDC° | Exhaust closes ATDC° | Duration° | Cam lift | Valve lift | Ideal hot clearance INLET | Torque range | Comments +ve & -ve | ||||
OEM. GT-6 Mk2, Spitfire Mk2/3, 2.5pi early | 308778 | 25 | 65 | 65 | 25 | 270 | 0.238 | 0.340" | 0.008"" | 1200 to 6800 rpm | This cam has best the performance of any road cam & runs well on Pi or SU carbs | Has rather small lift so needs an exceptional head to get high powers | ultimate power limited to peak 6600rpm, can get 75bhp/L! | ||
OEM. TR5/6 | 307689 | 35 | 65 | 65 | 35 | 280 | 0.252 | 0.360" | 0.008" | 2000 to 6800 rpm | Excellent torque from factory cam, can be raised to very good state of tune, but again head/exhaust must be very good to get high power | Also works v well on SUs/Spitfires, can be as high as 85bhp/L. | Although a torque improvement also can be made using a high ratio roller rocker on the INLET ONLY this cam tends to have high HC emission, because of overlap but low wear rates. |
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Camshaft 42 NLA | GT-ST42 | 37 | 67 | 71 | 33 | 284 | 0.290 | 0.412" | 0.010 | 2500 to 7000 rpm | An unusually economical rally cam developed by John Reid for FORD | Idle is rather rough on 2.5L, but runs quite well on 2L Pi & 1500cc | Flat spots etc led to retirement of this profile & development of new ones. | ||
Camshaft 43 CURRENT This is the camshaft, Triumph SHOULD have made. |
GTT43 | Time in at 108 deg | n/a | n/a | n/a | hybrid | 0.390" | .010" | 2000-7500 Peak power at 7000 Tacho points to 6 o'clock! |
A spectacularly successful "Wolf in sheep's clothing" profile with low wear rates. " but needs ideally 11:1 CR. | The first road cam to date, capable of a genuine 100bhp/L, very impressive |
Idle is so smooth & exhaust so quiet, it fools people into sounding like a stock engine.
The initial impression soon disappears, but the exhaust is usually quieter than the induction (!) With the right anciliaries it gives excellent results on a 2.5L too. |
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Camshaft 42A CURRENT |
GTT42A | time in at 107 degrees | n/a | n/a | n/a | hybrid | 0.300" | 0.426" | 0.010" | 1800-7000 | A v interesting cam for use where head skims (eg. GT6) can present problems 10-10.5:1CR | Shorter duration than 43, with somewhat more lift, so peak torque arrives a little earlier. Suits a good flowed head to perfection giving 110ftlb torque from 1300 Spitfire (like 43) | Smooth idle on weber or injection. Low wear rates, roughly similar power. | ||
Camshaft 457 CURRENT |
GTT457R | time in at 102 degrees | n/a | n/a | n/a | hybrid | 0.290" | 0.415" | 0.010" | 2800-8000 | Based on works camshaft family, so suits triumph engine perfectly | Longer duration cam than 43, more lift, & a lot more zip at the top. It still has a deceptively smooth idle & quiet exhaust but "comes on cam" VERY strongly at 4300rpm with an inlet "bark" |
Smooth idle on weber or injection. Low wear rates. 140bhp possible,a bit mad for the road(!) Needs 11:1 CR min. |
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Camshaft 55 CURRENT |
GTT55 | time in at 100 degrees | n/a | n/a | n/a | hybrid | 0.327" | 0.488" or 0.540" | 0.018" | 4400-9000 | Based on a works camshaft & latest head work, so suits a properly modified triumph engine perfectly | A longer duration cam than 457, with loads more lift, & a very strong top end. It has a smooth idle, but "comes on cam" quite viciously at 4500rpm extending to well beyond anything else done before | Smooth idle on weber or injection.Can have higher wear rates, so has to have a proper head/steel followers.120bhp/L possible. Much superior to KC"264".
This is a proper race cam, & needs a high CR |
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Ancient (Kastner) Triumph Competition cams | |||||||||||||||
Application | Part No | Inlet opens BTDC° | Inlet closes ABDC° | Exhaust opens BBDC° | Exhaust closes ATDC° | Duration° | Cam lift | Valve lift | Checking clearance | Operating clearance - hot | Torque range | Notes | |||
S-2 street/race | V 532 TSI/Isky now | 31 | 71 | 71 | 31 | 282 | 0.270" | 0.405" | .013 | .016 | 3500-6000 | Described as a road/race cam! | Narrow power band especially with the 6-2 exhaust type | Idle quite rough, high fuel consumption | |
S-4 race | V 579 TSI | 42 | 71 | 71 | 42 | 293 | 0.273" | 0.410" | 0.013 | 0.020 | 4000-6800 | This was described as a "race cam"! | Narrow power band especially with the 6-2 exhaust type | Rough idle, high fuel consumption | |
S-5 race | V 688 | 37 | 73 | 73 | 37 | 290 | .310 | .465 | .012 | .017 | 4000-7000 | Was described as an all out race cam!! | Even Narrower power band. Probably wouldn't work today either on most heads, especially with the 6-2-1 exhaust | Uses lift which probably is of no earthly use at the time it was released. | |
Good, bad or ugly aftermarket cams,based on Ford or various others. | |||||||||||||||
Manufacturer, Application | Part No | Inlet opens BTDC° | Inlet closes ABDC° | Exhaust opens BBDC° | Exhaust closes ATDC° | Duration° | Cam lift | Valve lift | Checking clearance | Operating clearance | Torque range | Notes | |||
Isky cam, road & race | Z-19 | 24 | 64 | 64 | 25 | 268 | .267" | .400" | .016" | .018" | 3000-6000 | Similar to a "Witor" idea of a Spitfire Mk3/Pi cam with just more lift | Just makes a little more torque. | ||
Isky Cam, Competition | Z-66+10 | 31 | 71 | 71 | 31 | 282 | .283 | .425 | .018 | 0.020 | 3500-6000 | Supposed to be a substitute for S2 above | I would imagine similar to SAH 357, ie. poor power delivery | ||
Kent Cam, Sports 'R' | TH2-6 | 39 | 76 | 76 | 39 | 295 | 0.261 | 0.370" | 2500-6500 | This is a FORD BCF2 profile for a x-flow 1600 with the valve clearance run tight. | |||||
Kent Cam, Sports 'R' | TH5-6 Also called fast road 83 | 37 | 63 | 73 | 27 | 280 | 0.293" | 0.416" | 2200-7000 | This is a FORD X-FLOW 234 CAMSHAFT | Apparently works well with mediocre heads/valves.Has a pronounced flat 2800-3800 | This is NOT a race cam. It is designed for a FORD 1600 | |||
Kent Cam, Supersports | TH6-6 | 42 | 68 | 78 | 32 | 290 | 0.309" | 0.439" | 3000-7500 | This is a FORD X-FLOW 244 CAMSHAFT | This is NOT a race cam | ||||
Kent Cam, Race | TH7-6 | 47 | 73 | 83 | 37 | 300 | 0.324" | 0.460" | 3800-7000 | This is a FORD X-FLOW 254 CAMSHAFT | This is claimed to be the ultimate Triumph race cam | Far from perfect cam, designed for a FORD. Has a LOT of lift. | |||
Kent Cam, RACE | 264 | 52 | 78 | 88 | 42 | 310 | 0.339 | 0.480 | 0.020" | 0.023" VERY CRITICAL | 3700-8000 | A cam for people who don't know about cams. Has very good torque, but suprisingly restrained top end..so 8000 is way past peak power. |
Although Torque is good, [Have seen as much as 125ftlb from a 1300(!)] power peaks at around 7200.Came to be more or less a de-facto STD race cam for the Spitfire, where CR is not an issue. |
BIG flat spots coming on cam. Can DO BETTER, because design is wrong for a Triumph. | |
Kent Cam, Sports Torque | TH12-6 | 31 | 59 | 67 | 23 | 270 | .287" | 0.407" | 1500-6500 | This camshaft is a Ford 224 Profile. | |||||
Piper Cam, Mild Road | TR6BP255 | 17 | 55 | 55 | 17 | 252 | .253 | .380 | .022 | 1000-5500 | We do NOT recommend PIPER cams | ||||
Piper Cam, Fast Road | TR6BP270 | 24 | 60 | 60 | 24 | 264 | .271 | .406; | .016 | 1500-6000 | We do NOT recommend PIPER cams | ||||
Piper Cam, Ultimate Road | TR6BP285 | 36 | 68 | 68 | 36 | 284 | .276 | .414 | .012 | 2500-6500 | We do NOT recommend PIPER cams | ||||
Piper Cam, Rally | TR6BP300 | 44 | 76 | 76 | 44 | 300 | .297 | .445 | .016 | 2800-7000 | We do NOT recommend PIPER cams | ||||
Piper Cam, Race | TR6BP320 | 52 | 80 | 80 | 52 | 312 | .327 | .490 | .014 | 3200-7500 | We do NOT recommend PIPER cams | ||||
Newman Cams, road/track | PH3 | 40 | 80 | 80 | 40 | 300 | 0.290" | 0.412" | .020" | .020 | 3500 - 7000 | This Newman cam is from a design that has not changed in 30 years | Newman cams have lower failure rates than most. | ||
Tiltech? Who are they anyway? |
298 | 45 | 73 | 81 | 37 | 298 | 0.352" | 0.499" | .012" | .015 | 4000-7000 | This cam is supposed to be the result of amazing technical prowess. To quote the designer, "These designs are better because they take advantage of the specific characteristics of the TR3/4 engine". Well apparently they don't, because we have them here! |
Flow from In the words of these people, "there is no downside to lift"! Well we can assure you there is. Also we note the "usual" advance of the exhaust timing by 8 degrees! |
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Tiltech? | 310 | 52 | 78 | 84 | 46 | 310 | 0.380" | 0.540" | .012" | .012 | 4500-7000 | This cam is another showing that anybody armed with a PC nowadays thinks they can design/evaluate a camshaft.
People are swearing by these in Triumph circles! We are starting to wonder how WE managed to get 100bhp/L from an engine with only 0.390" lift without using a computer? |
This is not a silly reflection from us. The hillman IMP engine (an ancient coventry made design) EASILY manages to run 100bhp/L figures & revs to 10 000rpm with only 0.360" lift. (getting another 15bhp/1000rpm) in the process. Maybe we do something wrong? |
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Canley Classic? /TLD? Another one who thinks they can (re-)design a cam? |
R2 | 37? | 73? | ? | ? | 285-290? | 0.310?" | 0.465" | ?.020" | ?.020" | 4000 - 6500 | This camshaft is clearly a retimed version of something else.(suspect based TH6 LATE)
To be quite honest we couldn't be bothered to waste time to find out what it is for sure! NASTY! |
we have rarely if ever seen such a truly AWFUL mess as this, The best description is a "lash-up".
We have never seen one of these work, & they knacker everything in an effort to struggle a few extra bhp out of what will be a horrible engine installation! |
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Racetorations road/track Another "so called" cam re-designer |
555/777/888 | ? | ? | ? | ? | 285-310 | 0.310-330" | 0.460-500" | Helpfully gives zilch details | No idea & not interested | 3500 - 7000 | These have never been properly designed or tested, as they consist of "yet another rip off", of some old motorbike design.. | These cams have higher failure rates than most, as the original pushrod (hemi) cam lobe shape was not designed for such high pressure. |
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-Some of the info here (including code), was made available with thanks to some US contributors-
We will update this later.