Triumph TR7 Sprint Guides, Photos and Videos

The Triumph TR7 Sprint version of the Triumph TR7 sports car was produced by the Triumph Motor Company (part of British Leyland) in 1977 in very limited numbers: probably no more than 61 in total. It used the 127 bhp, 16-valve, 2-litre version of the Triumph slant-four engine from the Triumph Dolomite Sprint, a highly tuned version of which, "rated at 225 bhp at 8000 rpm" by 1977, was used in the Group 4 TR7 cars of the BL works rally team, from 1976 until 1978. This was instead of the TR7 base model's 105 bhp, 8-valve, 2-litre version of the same basic slant-4 engine. The 16-valve version was originally specified in the Dolomite Sprint at 135 bhp, and carefully assembled, standard engines had been known to give a sustained 150 bhp on the factory test bed.[note 1]

The reasons why so few TR7 Sprints were produced has been a matter of some debate, since it was never a catalogued model. It is widely assumed that the TR7 Sprints were built with the intention of it being produced for sale, but cancelled after only a few had been made. The suggestions are that it was either cancelled as a result of industrial action or because the sales and marketing department did not want it, as it was not a sufficient improvement over the TR7 base model or because it could not meet emissions legislation requirements for the US market - at which the TR7 and later TR8 were primarily aimed. It has also been noted that none of the suggested reasons for cancellation are a good match for when the main production ceased about the end of June 1977.

There is, however, clear evidence that in 1977 BL had needed some – possibly about 50 - 16-valve engined TR7s as homologation specials, which had to be "suitable for the normal sale". This was to continue rallying the 16-valve TR7 into 1978, following a change to the FIA's rules, which applied to the TR7, and several other rally cars - including the Toyota Celica, Lancia Stratos, and Ford Escort RS1800 -, from the end of 1977. This change had removed the "100-off" rule that had previously allowed certain modifications to group 4 cars, like multi-valve heads, on production of only 100 "bolt-on option kits" and without production of any similarly modified homologating cars meant for normal sale. A series of 6 photographs with the title "TR7 Sprint Homologation", dated 1 November 1977 and held at the British Motor Museum, identify the role of the TR7 Sprint in this process. Following this (9 - 23 November 1977), at least 30 of the TR7 Sprints are known to have been transferred out of the keeping of Sales and Marketing to BL's Power Train Division - identified in the process of disposal of cars. A second approval for the use of the 16-valve head on the Group 4 TR7 rally car was granted by the FIA in February 1978 in time for its use in the Mintex rally of that year.

Engine: Triumph Slant Four 1,998cc 16 valve

Capacity: 1998 cc

Valves: 16

Compression ratio: 9.5:1

Fuel system: Twin 1¾" choke SU HS6 carburettors

Maximum Power: 127 bhp @ 5200 rpm (estimated)[note 1]

Maximum Torque: 122 lb ft @ 4500 rpm (estimated)[note 1]

0–60 mph: 8.5 seconds (estimated)

Max speed: 120 mph (estimated)

The improvements in the 0–60 time and top speed over the TR7's 9.6 seconds and 111 mph are not huge. However, the figures for the 16 valve version of the TR7 are almost identical to those for the US specification carburettor version of the 3.5 litre 135 bhp Rover V8 powered Triumph TR8, which are 120 mph and 8.4 seconds. Also, one of the then Triumph engine development engineers is quoted as saying "The real test was the 30–50, 50–70 [mph] times and here the Sprint was significantly superior to the 2V [2 valves per cylinder] engine and even challenged the TR8's abilities. Certainly, if we were going 'off site' the preferred vehicle to 'borrow' was a Sprint TR7 over all others and that includes the TR8."

Also, despite being specified at 127 bhp, Spen King related "how he went away on holiday and came back to find an engine running on the bed giving 150 bhp at the first build." This would be very close to the 153 PS DIN (±5%) that was given by the Rover V8 engine in the UK Specification TR8. Hence, it is possible that had Triumph produced the TR7 Sprint and TR8 to UK specification, as was apparently planned at one time, there would have been significant debate of their relative merits, some of it probably rather partisan in nature.

According to the British Motor Industry Heritage Trust (BMIHT) archives at the British Motor Museum, Gaydon, there are production records for chassis numbers ACH/4 to ACH/25, and ACH/00501 to ACH/00535 and ACH/00700: 58 cars.[note 2] Also, ACH 1 is identified by the TR Drivers Club, as UK registration WAC 274S, and that ACH 2 and ACH 3 existed might have been inferred from this: "One [unattributed] source states that there were three batches of Sprints, ACH 1 to ACH 25, ACH 501 to ACH 536 and ACH 700 on its own, a total of 62 vehicles." However, following a requested search of the BMIHT records it was discovered that "the build records we have for ACH/000535 cover 4 separate sheets and there is no record or build card for chassis number 536 as the next vehicle is chassis number 700." What production records there are at the BMIHT do not provide registration details from which cars might be traced; however, some further details of the cars known to have been produced are provided by the TR Drivers Club.()

While the 'A' in the ACH prefix to the commissioning numbers indicate that the factory TR7 Sprints were built at Speke, a Triumph engine development engineer is quoted as saying "Some if not all of these cars were definitely converted at Canley from 8-valve to 16-valve". The reason given for this is that "the Speke unions wanted added bonuses for dealing with 'non-standard' cars." However, there were at least some built on the production line at Speke: another Triumph employee, responsible for engineering liaison between Speke and Canley, is quoted as saying that "At the changeover in July 1977 (to the new common underframe) we built a batch of thirty TR7 Sprints."

The TR Drivers Club website gives details for only two of the first group of 25 chassis numbers: what was presumably the first prototype, WAC 274S, and one other, WAC 253S. Both known cars from this group were registered in Coventry in September 1977. It is suggested that most of the other cars in this batch were LHD and sold abroad. According an inspection of the BMIHT archives, of the cars in this batch of 25 chassis numbers, at least were 11 LHD (some records have been lost) and 3 were UK specification - the remaining 11 are 'unknown' but assumed to be LHD.

The first two cars of the second group of chassis numbers were both white, and registered in Coventry as VVC 696S and VVC 697S in August 1977. These were, according to an owner written article in the TR Driver's Club Magazine from 1991,() used for reliability testing. While there are no reliable details for BL's use of these actual cars, according to one source the procedure used with the TR7 and TR8 was to run a test car on the Belgian pavé track at MIRA for 1000 miles, "effectively providing wear harder than a vehicle might experience in a lifetime of normal use". The same source also states that "A related assessment exercise for the TR7 was the '90 day corrosion test', for which a prototype was built without the usual zinc primer or anti-corrosion treatments and the body painted white, the best colour to show up any rust streaks." A Triumph engineer is quoted as saying, "this prototype was run around a variety of road surfaces under wet conditions and then the damp areas were checked. The vehicle was then fitted with a series of nozzles which sprayed salt solution into these same areas".

Thirty cars from this second group of chassis numbers were sequentially registered SJW 521S to SJW 550S (see Figure 4) in Birmingham in three groups in November 1977, and went to the BL press garage at the Canley site, Coventry; presumably for publicity purposes. It is claimed that these press garage cars were stripped and re-trimmed, and possibly also re-sprayed.

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