TriumphTR6

Triumph TR6 Engine Numbers

A TR6 has no VIN: it has a commission number, whose prefix names its series, and an engine number whose prefix should match it. How to read both, where to find them, how the numbers run year by year, and how they tell an original car from a converted one.

The tail of a red Triumph TR6 with a TRIUMPH badge over the word INJECTION on its black rear panel, a wrap-round tail lamp and a wire wheel.
A TR6 PI's tail with its INJECTION badge under the TRIUMPH letters: a clue to the injected car, though only the commission number proves it.Draco2008 from UK, CC BY 2.0

Triumph called a car's chassis number its commission number, and on a TR6 it is the number that matters. The TR Register puts it plainly:

TR's originate from an era prior to VIN's (Vehicle Identification Numbers) and used a number identified as the Commission Number.

TR Register, "Buyer Beware: TR6"

It is stamped on an aluminium plate, and on British papers it appears as the car's VIN. Check it against the papers first, then against the engine number, whose prefix should match it. The British Motor Museum holds Triumph's build records from 1946 to 1981 and issues Heritage Certificates from them, and the TR Register's leaflet sends buyers to its TR6 registrar to authenticate a car from its registration, engine and body numbers.⁠1​2

Reading the numbers

The prefix names the series, CP or CR for the TR6 PI and CC or CF for the US TR6, and the letters after the serial say how the car left the factory:

MarkWhereMeaning
CPPrefixA TR6 PI, from 1968 to September 1972
CRPrefixA TR6 PI, from late 1972 to February 1975
CCPrefixA carburetted TR6 of the 1969 to 1972 model years
CFPrefixA carburetted TR6 of the 1973 to 1976 model years
LSuffixLeft-hand drive; on carburetted cars up to CC78520
USuffixA left-hand-drive car for North America, from CC78521 and on every CF
OSuffixOverdrive fitted at the factory
1 and PBefore the prefix, and at the endA car assembled from a kit in Belgium

Rimmer's catalogue dates the U to 1971 on. On Belgian cars TR-Register Deutschland prints the extra figure as a letter I, as in "ICP500-LP"; whether a plate reads 1 or I, no source read settles.

Where to look. On early cars the commission plate is on top of the left inner front wing (fender), under the bonnet (hood); on late carburetted CC cars and on every CR and CF it is on the left door post, below the striker. CP cars for Germany have it on the right-hand wing, and Belgian cars on the bulkhead, and American cars carry a second plate at the left of the windscreen (windshield). The plate also gives the paint and trim codes. The engine number is stamped on a lip at the rear of the block's left side, just below the spark plugs. Two body-number plates sit on the bulkhead, one fitted by the body maker and one by Triumph; the gearbox (transmission) number is behind the clutch cross-shaft, or above the starter's bulge on the right on later American cars, and the axle number is at the base of its housing.

CF58328U

  1. CFThe prefix: a carburetted TR6 of the 1973 to 1976 model years
  2. 58328The serial: the last number Canley gave a TR6
  3. UThe suffix: a left-hand-drive car for North America
An example: CF58328U, the last TR6, built on 15 July 1976.
A blue right-hand-drive Triumph TR6 seen from above and behind, with a TRIUMPH INJECTION badge on its flat black rear panel.
A car whose commission number should begin CP or CR: a TR6 PI, known by its INJECTION badge, at Sparkford, Somerset, in May 2017.Andrew Bone from Weymouth, England, CC BY 2.0
A dark green Triumph TR6 with black rubber bumper guards and red-band tyres, parked on a paved drive under palm trees.
And one whose number should begin CF: an American TR6 with the raised bumper of its last two model years.Transpoecon, CC BY-SA 4.0

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The numbers year by year

Rimmer's parts catalogue lists the first and last commission number of each year with its build date, taken from the factory's records. Its years are calendar years, each filed under a model year; for injected cars the model year is Rimmer's own label, not an American one. A few of its entries are misprints, noted below.

Calendar yearInjected cars, first to lastBuilt
1968CP25156 to CP25158From 28 November; CP25001 most likely a prototype, CP25002 to CP25145 kits
1969CP25159 to CP26998; CP50001 to CP50464From 2 January; CP26998's date is printed "10th Sept 68", for 1969; the 1970 model year from 1 September
1970CP50465 to CP52785From 1 January
1971CP52786 to CP54572; CP75001 to CP75454To 7 September, then from 27 September (printed "CP7544")
1972CP75455 to CP77718; CR169 to CR664CP77718 on 21 September; CR169 on 15 November, CR1 to CR168 kits
1973CR665 to CR2911; CR5049 to CR5612CR2911 on 17 October; CR5049 on 14 September, CR5001 to CR5048 kits
1974CR5613 to CR6630From 1 January
1975CR6631 to CR6701CR6701, the last PI, on 7 February
Calendar yearCarburetted cars, first to lastBuilt
1968CC25003L to CC27383LFrom 19 September; CC25001 and CC25002 not in the build records
1969CC27384L to CC32142L; CC50001L to CC51032LCC32142L on 19 December; CC50001L on 22 November
1970CC51033L to CC60902LFrom 1 January
1971CC60903L to CC67893L; CC75001L to CC78812CC67893L on 20 August; CC75001L the same day (printed "CC7881")
1972CC78813U to CC85737U; CF1U to CF4028UCC85737U on 5 October; CF1U on 11 September
1973CF4029U to CF17002UFrom 2 January
1974CF17002U to CF25777U; CF27001U to CF29580UCF25777U on 18 September; CF27001U on 22 August (CF17002U is printed twice)
1975CF29581U to CF39991U; CF50001U to CF52314UCF39991U on 23 August; CF50001U on 29 August
1976CF52315U to CF58328UCF58328U, the last TR6, on 15 July

The TR Register's leaflet groups the same numbers by model year instead, and its ranges are the ones the US TR6 page uses for the carburetted cars. It dates the last CC car to August 1972, where Rimmer's build record gives 5 October. The Vintage Triumph Register and TR-Register Deutschland each draw some of the breaks at other numbers, especially around the 1974½ model year. None of these lists counts cars. TR-Register Deutschland notes that Triumph skipped whole series of numbers and took cars from the line for experiments, so a range says how many numbers were issued, not how many cars were built; the versions page explains why the totals differ.⁠3​1​5​4

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The Belgian kits

The cars assembled in Belgium were all injected and left-hand drive, and their commission numbers gain a 1 in front and a P at the end, the TR Register says; their plate is on the bulkhead. Rimmer and TR-Register Deutschland, which takes its ranges from Bill Piggott, list the kits' numbers:

RimmerTR-Register Deutschland
CP25002 to CP25145CP25004 to CP25145, 1968
CP50002 to CP50436, "believed to be CKD"CP50002 to CP50436, 1969
CP54573 to CP54584CP54573 to CP54584, 1971
CR1 to CR168CR1 to CR168, 1972
CR5001 to CR5048CR5001 to CR5048, 1973

Rimmer's ranges hold at most 807 numbers, and the German list's 805, by our arithmetic. They are numbers, not cars, and TR-Register Deutschland says its list makes no claim to be complete; how many cars were built in Belgium, no source read says.⁠3​4​1

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Was the first TR6 a CC or a CP?

Fact check

CC25003L

Rimmer's catalogue, from the factory's build records: "First production car (built 19th Sept 68)"

CP25003

the Vintage Triumph Register: "first carb TR6 on record", built the same day

Our reading. Both give the same serial and the same day, 19 September 1968, and both make it a carburetted car, so only the Vintage Triumph Register's prefix is wrong: carburetted TR6s carry CC. Rimmer adds that CP25001, which the Vintage Triumph Register calls the first prototype TR6, was most likely a prototype, and TR-Register Deutschland, after Piggott, gives CP25003 as the first injected number on record, a different reading of the same number.⁠3​5​4

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Production

Production: how far the sources agree

13703, TR6 PI, 'Produced for the Home Market - 8370', 'Produced for the Export Market - 5333'
Disputed.
13702, TR6 PI, '13702 of the total were petrol injection models'
Disputed.
just under 14,000, TR6 PI, sold outside the US
Disputed.
13912, TR6 PI, Roger Williams (2014); equals the CP + CR commission-number spans exactly
Not yet confirmed.
8370, TR6 PI, home market (all PI): 'Produced for the Home Market - 8370'
Good sources agree.
5333, TR6 PI, export PI: 'Produced for the Export Market - 5333'
One good source.
78147, US TR6, TR6 Carb, 'Produced for the Export Market - 78147'
Disputed.
78142, US TR6, '78142 were carburettor US market models'
Disputed.
almost 78,000, US TR6, sold in the US as carburetted cars
Disputed.
77398, US TR6, Roger Williams (2014)
Not yet confirmed.
91850, all TR6s, 1968-76 ('91850 cars built 1968 to 1976'); counting rule not stated
Disputed.
94619, TR6, '94,619 TRs were built, of which 86,249 found homes overseas, only 8,370 being sold in the UK'
Disputed.
91310, TR6, Roger Williams (2014): 77,398 carburetted + 13,912 PI
Not yet confirmed.

  1. 13703TR6 PI, 'Produced for the Home Market - 8370', 'Produced for the Export Market - 5333'

    TR Register, "Triumph TR6 Buyers Guide" (facts sheet)⁠6

  2. 13702TR6 PI, '13702 of the total were petrol injection models'

    TR Register, "Buyer Beware: TR6" (2 pp. PDF leaflet)⁠1

  3. just under 14,000TR6 PI, sold outside the US

    Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: British Leyland Triumph TR 6PI und TR 6 (Vergaser) – Die Karmann Autos", TR-Register Deutschland, c. 2010, 13 pp. (PDF)⁠4

  4. 13912TR6 PI, Roger Williams (2014); equals the CP + CR commission-number spans exactly

    Wikipedia (DE), "Triumph TR6", 2026⁠7

  5. 8370TR6 PI, home market (all PI): 'Produced for the Home Market - 8370'

    TR Register, "Triumph TR6 Buyers Guide" (facts sheet)⁠6; TR Register, "Buyer Beware: TR6" (2 pp. PDF leaflet)⁠1; Moss Motoring, "Twenty-Five years of the TR6: A Nostalgic Profile", Oct 1994⁠8

  6. 5333TR6 PI, export PI: 'Produced for the Export Market - 5333'

    TR Register, "Triumph TR6 Buyers Guide" (facts sheet)⁠6

  7. 78147US TR6, TR6 Carb, 'Produced for the Export Market - 78147'

    TR Register, "Triumph TR6 Buyers Guide" (facts sheet)⁠6

  8. 78142US TR6, '78142 were carburettor US market models'

    TR Register, "Buyer Beware: TR6" (2 pp. PDF leaflet)⁠1

  9. almost 78,000US TR6, sold in the US as carburetted cars

    Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: British Leyland Triumph TR 6PI und TR 6 (Vergaser) – Die Karmann Autos", TR-Register Deutschland, c. 2010, 13 pp. (PDF)⁠4

  10. 77398US TR6, Roger Williams (2014)

    Wikipedia (DE), "Triumph TR6", 2026⁠7

  11. 91850all TR6s, 1968-76 ('91850 cars built 1968 to 1976'); counting rule not stated

    TR Register, "Triumph TR6 Buyers Guide" (facts sheet)⁠6; TR Register, "Buyer Beware: TR6" (2 pp. PDF leaflet)⁠1; Vintage Triumph Register, "TR6" (history, year-by-year changes, US production table, buyer's guide)⁠5; Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: British Leyland Triumph TR 6PI und TR 6 (Vergaser) – Die Karmann Autos", TR-Register Deutschland, c. 2010, 13 pp. (PDF)⁠4

  12. 94619TR6, '94,619 TRs were built, of which 86,249 found homes overseas, only 8,370 being sold in the UK'

    Vintage Triumph Register, "TR6" (history, year-by-year changes, US production table, buyer's guide)⁠5; Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 2: TR5, TR250, and TR6", Ate Up With Motor, 7 Nov 2012⁠9; Charlie Calderwood, "Datsun 240Z vs Triumph TR6: the battle for America", Classic & Sports Car, 1 Feb 2023⁠10; Moss Motoring, "Twenty-Five years of the TR6: A Nostalgic Profile", Oct 1994⁠8; Fred M. H. Gregory, "TR8 V-8: A mighty Triumph" (road test), with the sidebar "A String of Triumphs", Motor Trend, Jun 1980⁠11

  13. 91310TR6, Roger Williams (2014): 77,398 carburetted + 13,912 PI

    Wikipedia (DE), "Triumph TR6", 2026⁠7

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Sources

Sources are given as plain text; their addresses are on the sources page.

  • Primarymade at the time, by the maker or by people who were there
  • Referenceserious later work: clubs, specialists, magazines, books
  • Uncheckedencyclopaedias and enthusiast sites: cited beside a good source, named in the sentence, or marked Unchecked
  1. TR Register, "Buyer Beware: TR6" (2 pp. PDF leaflet), p. 2, "TR's originate from an era prior to VIN's …"; p. 1, the V5 and the registrar; p. 1, prefixes, suffixes, L to U at CC78521, the Belgian marks, the plate positions, converted cars; p. 1, the ranges by model year; the last CC, August 1972; p. 1, the Belgian cars: PI, left-hand drive, "1" and "P", the plate on the bulkhead; p. 1. Reference
  2. British Motor Museum (BMIHT), "Heritage Certificates", the service: build records, 1946–81. Primary
  3. Graham Robson (foreword), Triumph TR6 1969–1976 Parts & Accessories Catalogue, Rimmer Bros, edn 2.2 (source code TR600313), p. 5, "'L' or 'U' (1971 on) for left hand drive … and 'O' for overdrive"; Location of serial numbers; p. 5, Vehicle identification: first and last car of each year, with build dates; p. 5, the five CKD ranges; "believed to be CKD"; p. 5: "First production car (built 19th Sept 68)"; CP25001 most likely a prototype; CC25001–02 not in the build records. Reference
  4. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: British Leyland Triumph TR 6PI und TR 6 (Vergaser) – Die Karmann Autos", TR-Register Deutschland, c. 2010, 13 pp. (PDF), p. 2, "ICP500-LP"; p. 2, its own breaks; skipped numbers and experimental cars; p. 2, the CKD ranges after Piggott; not claimed to be complete; p. 2, CP25003 as the first recorded PI number, after Piggott; p. 1; p. 2. Reference
  5. Vintage Triumph Register, "TR6" (history, year-by-year changes, US production table, buyer's guide), change list, '73: the plate on the door post; Spotter's Guide: its own year breaks; Spotter's Guide, '68: "CP25003, first carb TR6 on record"; CP25001 "first prototype TR6"; TR6 page, 'Production Dates and Numbers'; TR6 page, history text. Reference
  6. TR Register, "Triumph TR6 Buyers Guide" (facts sheet), all US cars left-hand drive; Facts & Figures, 'Production Figures TR6 PI'; Facts & Figures, 'Production Figures TR6 Carb'; Facts & Figures, introduction. Reference
  7. Wikipedia (DE), "Triumph TR6", 2026, lead section. Unchecked
  8. Moss Motoring, "Twenty-Five years of the TR6: A Nostalgic Profile", Oct 1994, text. Reference
  9. Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 2: TR5, TR250, and TR6", Ate Up With Motor, 7 Nov 2012, 'TR in Twilight'. Reference
  10. Charlie Calderwood, "Datsun 240Z vs Triumph TR6: the battle for America", Classic & Sports Car, 1 Feb 2023, factfile, 'Triumph TR6'. Reference
  11. Fred M. H. Gregory, "TR8 V-8: A mighty Triumph" (road test), with the sidebar "A String of Triumphs", Motor Trend, Jun 1980, sidebar 'A String of Triumphs' (read by the TR8 agent, notes-tr8.md). Primary

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