“No Alfa Romeo will ever be powered by a Fiat engine”
Ettore Massacesi, Alfa Romeo President, 1981
Ettore Massacesi famously uttered that defiant promise as Fiat were attempting to bring the struggling Alfa Romeo under their vast umbrella in the 1980s. This blinkered, elitist view still echoes through into today with the purists loudly declaring the RWD 75 as the last “true Alfa Romeo” model.
Long considered Alfa’s USP, their race-bred engines really were the cuore sportivo that powered the marque through their heyday and kept them on life support during the troubled 1980s. For many, the very inclusion of Fiat executives in the engine design and manufacturing discussions suddenly diluted everything that had made Alfa special.
Which is their loss, in our opinion, because in ignoring everything post-1986 they’re missing out on some of the best driving thrills of the past twenty or thirty years. We’ve already composed our loveletter to the ‘Busso’ V6 which, of course, bloomed into a quad-cam, 24v powerhouse under Fiat’s direction. We do also genuinely believe that, however unfashionable it may be now, the superb JTD (the world’s first mass-produced common-rail diesel engine) helped revitalise the brand, particularly in the UK market, through the late 1990’s and well into the 2000s.
But another highlight from the same period is undoubtedly the Twin Spark, which this post is concentrating on. Given the pet-name ‘Twinny’ by enthusiasts; this four-cylinder, eight-plugged unit set the beat for pretty much the entire Alfa Romeo range from its birth in 1995 right up to 2010. Its story, though, started long before this…
A Racing Pedigree
In fact, it stretches all the way back to 1914 before Nicola Romeo had appended his name to the A. L. F. A. brand. Tasked with turning the 40/60 model into an outright Grand Prix winner, chief engineer Giuseppe Merosi developed a 4.5-litre, 4-cylinder, 16-valve engine with two spark plugs per cylinder to bolster the road car’s performance.
Although the resulting A. L. F. A 40/60 GP didn’t actually compete in a race until seven years later (and even then, it limped to retirement with a broken radiator), its impressive stats indicated there was method in Merosi’s madness. An engine capable of producing 88 bhp at 2950 rpm in this period was no mean feat. So memorable was this technical trickery that it lingered around in the automotive ether until 1965, when Carlo Chiti and his magicians at Autodelta were gifted a vanilla Giulia Sprint GT, a bucketful of lira and told to turn it into a thoroughbred race winner.
The standard 1600 twincam engine was good for 105bhp out of the box and the Sprint GT’s lithe handling had already won plaudits, but Autodelta saw untapped potential in the package. Besides drilling holes through everything in sight and shedding over 400lbs of weight, they also reanimated Merosi’s prototype concept from Alfa’s annals. The bialbero was repurposed with lightweight magnesium components, the anaemic 40mm carburettors were swapped out for some full-fat 45’s and, most daringly, a new double ignition head was slapped on top. In full race spec the ‘twin-plug’ (as Autodelta named their version of the system) 1600’s were reportedly capable of 170bhp and utterly dominated touring car meets around the globe for the next six years.
Chiti continued to experiment with the GTA, building 1300 Juniors, single-plug versions and even toying with forced-induction with the shortlived GTA-SA. But, throughout this period, the twin-plug engines remained largely for use on the track. For the next stage in the evolution of Alfa’s Twin Spark, though, the technology would be made available for all.
Got A New Motor?
Fast forward to the mid 1980s and Alfa were still relying on the 30-year-old ‘Nord’ twincam (with some back-up from Sr. Busso’s masterpiece). With their competition churning out novel 16v units almost every week, they desperately needed a new engine to keep pace with developments. However, they weren’t exactly flush with the cash needed to plough into years of experimental R&D. So lopsided were the balance sheets that, since the late 1970s, they had been shutting their factories for two weeks out of every eight in an attempt to restrict the haemorrhaging of money. To avoid mass unemployment, the Italian Government even footed the wages of the workforce while tools were downed.
As the saying goes, ‘necessity is the mother of invention’ so a quick, cost-effective fix was cooked up, repurposing the trusty ol’ twincam for this new era. Four valves per cylinder with one sparking plug in the centre was de rigeur for innovative engineers of the time, but the Nord’s 44mm inlet valve meant there was simply no space to accommodate this. So, once again, Merosi’s two-spark-plugs-per-cylinder blueprints were dragged out of the archives.
When the new 2.0 8v Twin Spark 75’s were launched in 1987, though, they’d done a bit more than just ramming another plug into each cylinder. The old-school hemispherical combustion chamber and head of the Nord had been completely reworked. Beyond giving us nerdy engine geeks something to study (see below if you’re interested in the technical side), the results spoke for themselves. The 2.0 75 Twin Spark (although retaining its predecessor’s existing 84mm bore and 88.5mm stroke) gained 18bhp and 7lb-ft of torque over the outgoing 2.0 single-spark models, while also returning considerably more efficient fuel consumption.
Although borne of a need to keep up with 16v advancements on a shoestring, the Twin Spark can definitely still be considered a success. Both in terms of keeping die-hard Alfisti happy from a performance perspective, as well keeping sales relatively buoyant in the showrooms.
It went on to be made in 1.7, 1.8 and catalysed 2.0-litre forms and powered the 75, 164 and 155 models. For the 155, further enhancements had been made including a longer stroke (now up to 90mm), slightly shorter block, shortened & lighter rods, pistons cooled by oil jets and inclined ports for better gas flow. For our money, the 155 2.0 8v Twin Spark is home to one of Alfa’s very finest engines. An absolute joy to drive and, after a cumulative 40 years’ of honing and learning, rock solid reliability.
Here Comes The Science Bit - Concentrate!
When it comes to ignition sparks, then, why is it that two is better than one? Well, in its simplest form, the answer is purely that it delivers better combustion. This, of course, results in stronger performance but with less fuel wasted and unburnt, it also improves efficiency.
Being more technical, what you have to consider is how the ‘flame front’ (ie, the perimeter of the combustion area) spreads out within a cylinder. In an ideal world when the spark plug fires the fuel/air mixture will immediately catch light, burning consistently throughout the chamber so that, by the end of the stroke, there is nothing left but the exhaust gases ready to be expelled. In reality though, when all this takes place within one two-hundredth of a second, it’s not that perfect. As bores in engines get larger, so it takes longer for the flame front to expand fully within the cylinder (chasing the piston down its stroke, in effect). What two plugs achieves is two flame fronts converging together, essentially burning the fuel in the cylinder quicker and leaner.
A Brave New World?
When handed full control of Alfa Romeo, Fiat had no shortage of hurdles to overcome in righting the listing ship. One of the main tasks was to deliver an engine unique and interesting enough to appease the brand’s hardcore followers. To keep costs from spiralling out of control under this enlarged regime, the bean counters had consolidated all Fiat, Lancia and Alfa powertrain responsibilities into a single factory in the quiet area of Pratola Serra. Not only were all engines to be built under the same roof, but to minimise tooling and set up costs it was decided that they each had to be created from a standardised genesis to boot.
The “modular engine”, as it came to be known, was adapted into countless different iterations. There were four and five cylinder versions, some naturally aspirated while others received turbochargers, capacity ranged from 1.4-litres up to 2.4-litres and there were even diesel and petrol fuelling systems all built on this same foundation.
From a manufacturing efficiency point of view, this was a massive leap forward. But in terms of delivering an engine with genuine character and individuality - the likes of which Alfa were known for, of course - it was an immensely difficult task.
Desperate for a USP, some bright spark (see what I did there?) in the marketing department decided they should retain the Twin Spark badging. The name had become almost entwined with Alfa in the public’s minds after the success of the 8v units in the 75, 164 and 155. The mysterious phrasing also helped perpetuate the marque’s ‘otherness’ and exclusivity.
When this idea was presented to the engineers, though, talk the marketing spiel fell on deaf, irritated ears. Adding dual-ignition to the ‘Pratola Serra’ engine added no technical benefit they could see, nor did it solve any apparent inherent problem. In fact, quite the opposite; implementation of two plugs per cylinder actually created issues they were suddenly being asked to design their way out of.
The eventual solution, although somewhat artificially tacked-on, was nothing if not inventive. At first glance, everything is where you would expect it to be on a modern four-pot. Nice single spark plug bang in the centre of the four-valves? Check. But, hang on. What’s this over here? A smaller spark plug added right at the edge of the combustion chamber? With this placement, any enhancement to performance was always going to be negligible. What it does deliver, though, is increased efficiency when the air-to-fuel ratio is low under minimal loads. It’s this which gives the 16v Twin Spark its renowned smoothness - something sorely lacking from its eventual successor, the JTS.
Non-Identical Twinnies
Although the Twin Spark system added little in terms of outright performance to these new 16v engines, they first appeared on the scene in two of the most outright sporty models to bear the biscione in years; the 916 GTV and Spider. Launched in 1995 in only 1,970cc guise, they produced 148bhp and 138lb-ft of torque. These early examples can be spotted by their alloy cam covers and are widely referred to as ‘CF1’ engines.
| Size | Type | BHP | lb-ft | Model | 0-60 | Top Speed | Years | |
| 1.4 | CF1 | 102 | 91 | 145 / 146* | 10.6 | 115 | 97-00 | |
| 1.6 | CF1 | 104 | 106 | 145 / 146 | 9.7 | 121 | 97-00 | |
| 155 | 11.4 | 121 | 95-98 | |||||
| 1.8 | CF1 | 138 | 120 | 145 / 146 | 8.5 | 127 | 97-98 | |
| 155 | 10.0 | 127 | 95-98 | |||||
| 2.0 | CF1 | 150 | 137 | 145 QV / 146 ti | 8.0 | 130 | 95-98 | |
| 155 | 9.0 | 130 | 95-98 | |||||
| GTV / Spider | 8.4 | 134 | 95-98 | |||||
| 1.6 | CF2 | 118 | 108 | 147 | 10.2 | 121 | 00-01 | |
| 156 | 10.5 | 124 | 97-06 | |||||
| 1.8 | CF2 | 142 | 125 | 145 / 146 | 9.1 | 131 | 98-00 | |
| 156 | 9.3 | 130 | 97-00 | |||||
| GTV / Spider* | 9.2 | 130 | 98-00 | |||||
| 2.0 | CF2 | 153 | 138 | 145 QV / 146 ti | 8.3 | 131 | 98-00 | |
| 156 | 8.6 | 134 | 97-00 | |||||
| 166 | 9.6 | 132 | 98-00 | |||||
| GTV / Spider | 8.4 | 134 | 98-00 | |||||
| 1.8 | CF3 | 138 | 120 | 156 | 9.4 | 129 | 01-06 | |
| GT | 10.6 | 124 | 03-10 | |||||
| 2.0 | CF3 | 148 | 133 | 156 | 8.8 | 133 | 01-02 | |
| 166 | 9.8 | 131 | 01-07 | |||||
| *LHD Models Only | ||||||||
The old 8v Twin Sparks were dropped from the 155 2.0 models soon after this, and the new Fiat-developed engines were drafted in to hot-hatchify the 145 and 146 via the Cloverleaf and ti. A year later, and the 4-cylinder 155 range was refreshed further with all-new 1.6 and 1.8-litre 16v models replacing the Nord-based units entirely.
In 1997, the 145/146 lost the characterful boxer engines, ending an ancestry that stretched back to the much-loved Alfasud and leaving the 12v-Busso-V6 as the last fully Alfa-designed engine on sale. Base-model 145.146’s were now offered with the same 1.6 and 1.8 units launched in the 155 and, in LHD Europe at least, there was also a short-lived, entry level 1.4-litre (104bhp) 16v Twin Spark.
The birth of the 156, a massively important model for the marque’s continued existence, also brought on the next round of developments for the Twin Spark. This new evolution dropped the alloy rocker cover in favour of plastic, but also went through more technical changes. A new variable-length inlet manifold was fitted to the 1.8 and 2.0 versions, upping the power. GTV and Spider purchasers on the continent could now opt for 1.8 power, but like the baby 1.4 before it, this didn’t last long.
The final phase for the Twin Spark engine came in 2001, with the ‘CF3’ gaining extra catalysts (bringing the total to 3!) and an electronic throttle management in order to meet the Euro 3 emission benchmarks. Although on paper this apparently had little effect on power or performance, in our opinion there is a noticeable difference in driving an earlier CF1 or CF2 and then jumping straight into something with a CF3 under the bonnet.
The launch of the 2.0 JTS in 2001 with it’s run-of-the-mill single spark plug sounded the death knell for the Twin Spark, although it refused to die without a fight. It continued on in most models up to 2006 (the 147 was never built with the JTS engine, due to higher costs) but actually clung on for dear life for another four years..
After a century of illustrious history, numerous different iterations, millions sold and almost endless thrills for keen drivers, the Alfa Romeo Twin Spark quietly shuffled off the automotive stage in the last 1.8 GT model to roll off the production line in 2010.
We don’t want to sound like those doomsayers proclaiming the 75 to be the last ‘true Alfa’ here, but it seems to us that there’s been little of the engineering magic to excite Alfisti since the Twinny’s demise. The 1.75 TBi is a great little engine and delivers power way beyond it’s meagre capacity, but it never really found a fitting home. The Maserati-based 2.9, twin-turbo V6 powering the current generation of Stelvios and Giulias is an incredible piece of work, sure, but it hasn’t ignited the sort of sales explosion enjoyed by the humble 156, has it?
We don’t really care if it can be considered part of an owner’s club version of the Alfa Romeo canon, or which brand had an input into its DNA. For us, the Twin Spark is and always will be a legendary engine.