RESTORING & ENJOYING Resto Hero: Triumph TR6 EFI Two classics given a modern twist with electronic fuel injection.

Keith Warren built his dream TR from a ‘painting by numbers’ EFI kit, then knocked up a self-build Midge from leftovers

Keith Warren is clearly a man who accepts nothing less than perfection. Having restored his 1972 Triumph TR6 to near-concours standard, the Lucas Petrol Injection system didn’t meet his high standards. Even after several new metering units and injectors, it remained problematic.

‘It was difficult to start after standing for a few days, says Keith, ‘and often when out I would go to restart it and an injector would be blocked.’

His journey towards total engineering perfection led him inevitably to modern electronic fuel injection, with fuel and sparks governed by a mysterious black box, the ECU.

Keith acquired his TR6 back in 1983, following on from a Spitfire and an MGB he had enjoyed before. He says he wanted the big TR because: ‘I fancied a big six-cylinder engine, so a TR6 was the next logical step up’. Straightaway, he dived into restoring the TR, doing everything himself

‘For the TR6, I chose to use an ECU from Emerald for ease of mapping’

including a smart respray in Diy-friendly cellulose paint. His project featured some self-fabricated upgrades, including a rear end conversion from lever arm to adjustable telescopic dampers. ‘There wasn’t a kit available at the time,’ say Keith, ‘so I made up brackets to my own design, bolting them to the chassis.’ He also fitted a rear anti-roll bar complimented by a stronger front bar, so the car corners in a very flat and ‘planted’ manner.

So far, we’ve got a story of a high quality yet fairly conventional home restoration but Keith and his

TR6 soon ventured off-piste. He picks up the story: ‘I had the Lucas PI system working, but it was never very reliable after the introduction of unleaded fuel. Starting was difficult and injectors would often block, needing to be removed and cleaned before the engine would run properly again’. He knew a few club friends who had experimented with electronic fuel injection to replace the old Lucas mechanical system. Their experiences encouraged Keith, then in 2011, he saw a complete kit marketed by EFI Conversions at a car show. ‘It was based on a commonly available Vauxhall throttle body and injectors,’ say Keith, ‘and I chose an ECU from Emerald for ease of mapping.’ The kit included absolutely everything, even new inlet manifolds and a wiring harness. Again, keeping the project straightforward, a new crank pulley with its trigger wheel to control ignition timing was supplied on an exchange basis.

Having installed the EFI components, Keith was able to fire up the engine using a standard fuel and ignition map that contained basic rather than optimum settings. So far, so good, but inevitably, difficulties began to creep in. ‘The engine would start and run,’ recalls Keith, ‘but there were massive flat spots.’ As soon as his freshly-rebuilt engine was run in, Keith went to Dave Walker at Emerald for a rolling road session to optimise the ECU mapping.

The rolling road tuning helped, but Keith still wasn’t happy: ‘The engine was pulling better at the top end, but wouldn’t run smoothly at low revs’.

This was disappointing, as clean running across the entire range of engine speed and throttle opening should be a big benefit with EFI. Dave Walker suggested the 150bhp standard TR6 camshaft could be the problem. The EFI kit uses a single throttle body unlike the Lucas PI, which has individual throttle butterflies for each cylinder. Theoretically, the aggressive valve timing of the original TR camshaft could cause pulsing back from the inlet valves to the plenum.

The answer was a new camshaft from Triumph specialist Chris Witor, which has slightly milder valve

timing from a 2.5PI saloon, with extra lift on the inlet valves to compensate. Another rolling road session followed the fitting of the new camshaft and this time, Keith was happy: ‘The engine now pulls strongly across the rev range. It has a peak power output of 148bhp and recently returned 36mpg on a run to the Triumph show at Stratford.’ Those figures prove the benefits of EFI over Lucas PI; the so-called 150bhp TR6 never made more than about 135bhp and economy rarely topped 30mpg.

Emboldened by his success with the TR6 EFI,

Keith wanted to convert his other classic to EFI, too. It’s a JC Midge kit, finished in 1997 to his usual high standard, using a Triumph Spitfire MKIV chassis and mechanical components. What happened next should cause all owners of small Triumphs to pay attention, as before he started the conversion, Keith’s Midge was a completely standard 1300cc Spitfire under the skin. Building on the experience gained when fitting EFI to his TR6, he decided to use the less expensive route of putting together an EFI system himself, using readily available components.

‘I found the injectors and throttle body on a crash-damaged Rover 25 in a local scrapyard, all still in perfect working order’ says Keith. The biggest challenge was to fabricate his own inlet manifold and plenum, so he could fit the Rover parts to the Triumph engine. Other major parts include an ECU from Canem sited in an alloy box on the bulkhead, and the trigger wheel and crank position sensor, which came from the aptly named Triggerwheels. com. Welding a new fuel supply outlet to the standard Spitfire petrol tank provided a scary

moment: ‘I flushed the tank numerous times to clear any remaining petrol vapour then held a blow lamp on a broomstick to the neck as a test,’ he says. It didn’t explode, so Keith felt safe to start welding.

Needless to say, he’s executed his Midge EFI conversion to the highest of standards and, after installation, the initial start-up was entirely fuss-free. Following a tuning session on a rolling road, the standard Spitfire MKIV engine is making 65bhp at the flywheel, a useful increase from Triumph’s claimed 61bhp. The Midge EFI can easily better 40mpg fuel economy on a run, proving the value of modern engine management.

Keith’s EFI journey is impressive. Starting with little electronic experience and scant knowledge of modern engine management technology, he has successfully converted not one but two classics, learning the ropes with a kit on his TR6 and stepping up to self-build for the Spitfire-powered Midge. He sums it up: ‘using a standard kit felt a bit like cheating. On the Midge, I can say I’ve done it all myself’. The increased power output, economy and total driveability of his cars speak for themselves.