four cylinder engine

Austin-Healey appeal in its purest form? That comes with the four-cylinder 100. There’s something viscerally appealing about an engine with four big cylinders. Once your engine’s capacity is approaching 2.7 litres, accepted rules of engineering politeness suggest that your swept volume should be distributed between six cylinders. Using just four seems uncouth, the route to bigger, fewer, more obvious bangs.

But there are advantages. Four pistons and big-end bearings generate less friction than six. And a four-pot is both shorter and lighter than a same-capacity six-pot. Consider simultaneously all the factors so far mentioned, and you have the fundamental difference between an original Austin-Healey 100 and its six-cylinder descendants, the 100-6 and the 3000. Now think on this: a Healey 3000 has 65% of its weight on the front wheels, while the racing 100 you see here, admittedly lightened with aluminium panels and using optimally positioned ballast to bring it back up to the homologated weight, has that weight equally distributed front and rear.

So a big, lusty, torquey four-pot in a well-balanced ‘Healey ought to be a route to considerable driving entertainment. Which is why we’re at JME Healeys, based in an original Healey building in The Cape on the north side of Warwick, with a quartet of four-cylinder ‘Big Healeys’ to try.

I’ve wanted to do this for years, the longing fuelled variously by delving into the engine bay of a stricken 100S on the way to Le Mans back in the early Noughties, driving a restored late 3000 recently and wondering how much friskier its lighter-footed ancestor might feel, and sampling back in 1984 the actual Motor road-test 3000 of 1964, nicely restored, and wondering the same thing. Its gearlever came off in my hand, but we won’t go into that here.

THE CAPE SOUNDS as if it should be a marine headland, but actually it’s close to a canal by which stands the Cape of Good Hope pub, and opposite what used to be a pond before it got filled in. JME inhabits the former Healey prototype-build and competitions department building in what is now a kind of organically evolved business park. The late Jonathan Everard acquired the building in 2008, and he and his sons Chris and Dan renovated it back to authenticity from its most recent previous role as a carpet warehouse.

The family still runs this mecca of Big Healeys, and Chris and Dan have gathered together four flavours of Healey 100 – named for the approximate maximum speed – which together will thoroughly plug my educational gap. To set the scene, I’ll start with a standard road car in its first incarnation, the BN1 with a three-speed gearbox.

Three speeds? That sounds very basic, the sort of ratio-number you’d find in a 1950s American car or their smaller British namesakes as made by Ford or Vauxhall. Austin-Healeys were destined to sell in greater numbers in the US than anywhere else, so was that why there were so few ratios? No; it’s simply that the Austin gearbox that came with the engine had an unusably low first gear, so it was blanked off in the selector gate. And, crucially, an overdrive working on second and top gears was added behind the gearbox, so there are actually five forward ratios. Job done, with a synchromesh first gear to boot.

As for the engine, it evolved from Austin’s first-ever overhead-valve unit, created for the post-war Austin 16 with 2199cc and a very long stroke. It then powered Austins Hampshire and Hereford before being bored out to 2660cc for the catastrophically misjudged Austin A90 Atlantic. This twin-carburettor engine was just right for the ‘Healey, though, which weighed over 400kg less than the Atlantic and, thanks presumably to a freer-flowing exhaust system, benefited from 90bhp at 4000rpm compared with the Atlantic’s 88bhp at a very lazy 3800rpm.

In its metallic Ice Blue paintwork and low-slung curves, the BN1 is as archetypal as an early 100 could be. It has its original registration number, that intriguing windscreen able to slide downwards and forwards against a pair of return springs for a gale-inducing reduction in frontal area, the full-size, vertically slatted grille that’s a widened version of those found on pre-Austin Healeys, and drum brakes behind the wire wheels.

Inside, its dark blue trim is marvellously minimal, even if the thin-backed seats are trimmed in leather, with just an open shelf and a grab-handle for the front passenger and an oval binnacle for the driver behind the huge steering wheel with its thin rim and three paired-wire spokes. Of course, there are no wind-up windows, only sidescreens.

The gearlever seems almost an afterthought, emerging from the far side of the transmission tunnel and angled towards the driver, and its strangeness is compounded by a reversed gate that puts first gear towards you and back. And now we’re off, with a gritty burble overlaid by the multi-part-harmony whine of the Austin gearbox, and this ‘Healey is instantly feeling smaller and squirtier than I expected. Low inertia and ready torque are a great combination.

It sits low, of course, but on standard-height springs it retains enough suspension travel and ground clearance to be civil and usable. The worm-and-peg steering is accurate enough for me not to crave something crisper, and I can feel exactly what is happening under 70-profile Avon radial tyres far grippier than anything on offer in 1954. Even the drum brakes feel up to the job, although, were they to let me down, my chest would probably be impaled by a steering column whose far end is ahead of the front axle line. Best not to think about that.

Under the BNl’s bonnet are some interesting details for the Healey-fancier. The Burgess ‘wet-type’ pancake air filters contain not their original oiled wire mesh but modern, more effective paper elements, and the cylinder head flaunts in bare metal the fact that it’s made not from cast iron but aluminium. That means it’s not original, but the originals crack and today’s aluminium re-makes don’t. Besides, the owner can do exactly what he wants with this car because he has owned it from new, having been given it before he was even old enough to drive on the road.
In later life it sat for many years in a barn, but JME extracted it in 2008 and restored it to a fabulous standard. ‘It was still on the buff logbook, ‘says Chris, ‘but we managed to get the number back.’ Tyres apart, it must surely drive as it did when it left Austin’s factory at Longbridge. As an Austin-Healey familiarisation template, it’s perfect.

THUS PRIMED, I slot into the red leather driving seat of the 100M. A total of 601 of these were built at the factory, with more cars converted from standard BN2s using Austin-Healey’s kit of parts. Our black-over-red example is a post-production conversion, but as a 1956 BN2 it already had a proper four-speed gearbox, slightly less bulbous front wings, a curved crease in the lower rear wings behind the wheels, and the option of two-tone paint.

The engine conversion involved larger, longer-bodied SU H6 carburettors fed through a filter-less airbox, plus a hotter camshaft and a compression ratio raised from 7.5:1 to a dizzy 8.1:1. This gave 110bhp at 4500rpm. Our car here also has a bigger-diameter exhaust system, an ITG foam air filter and the vital aluminium cylinder head, so gives a little more. The louvred, strap-secured bonnet is as fitted to all 100Ms, but the ribbed rocker cover in polished aluminium and the wood-rimmed Moto-Lita steering wheel are aura-enhancing additions.

So eager does the 100M feel that I’m soon heading far out into country roads, revelling in the relative revviness, sailing along on the easy torque. This ‘Healey feels crisper in every way, its four-speed gearbox plus overdrive giving a closer spread of more ratios as I savour the sensory stimulation of what feels like a properly fast car.
Along with the motive urge comes the wonderfully intuitive sense of control typical of a simple design with a front engine, rear-wheel drive and no quirks of suspension geometry. A friendlier sports car is hard to imagine. I’d happily drive to John O’Groats right now, provided the rain stays away.

BUT I CAN’T, BECAUSE the most prized of all Healey 100 incarnations now awaits. This is the 100S, aluminium-bodied and designed for racing. Only 55 of these were made, five of them in what is now JME’s workshop, the rest at Longbridge. Most were painted in Old English White with blue flanks, but the first owner of this particular example, David Shale, decided he preferred British Racing Green for what was to be his club racer and had it repainted straight after he bought it, ready for its 1955 racing debut at Goodwood.

EVV 106 has quite a provenance, being one of only four 100S models to be sold and raced in the UK, most having headed across the Atlantic. Later owners included saloon ace Tony Lanfranchi, and the owner before the current one had it restored by JME in 2006 before entering most of the key historic events, including the Mille Miglia and the Goodwood Revival. From new it has had the unique 100S feature of a David Brown gearbox as fitted to contemporary Aston Martins, so there’s a short lever emerging conventionally from the centre of the transmission tunnel.

Outside, the obvious identifiers are the low windscreen in Perspex, the lack of bumpers, a giant fuel filler cap and the pointed-oval front grille with its vertical slats, previewing the more ornate version that would appear on the 3000s. The hood is missing, too, helping towards a total weight loss of 91kg compared with a stock BN2. Then you open the louvred bonnet and do a double-take. Has someone turned the engine round?

No, but the cylinder head – aluminium again, but always so – is reversed so the carburettors (hefty SU H8s) are on the ‘Healey’s right side and the distributor is on the left, driven from the top of the oil pump where the tachometer drive would normally be, instead of directly from the camshaft. Why such radical re-engineering? Because by no longer having the pushrods running past the inlet and exhaust ports, these ports can be individual instead of siamesed, they can be bigger, and they can breathe better. The result of all this was 135bhp in period and, thanks partly to what Chris Everard describes as a ‘funny camshaft’, around 170bhp now
EVV 106 sold for £673,500 in the Bonhams auction at the 2014 Goodwood Festival of Speed, to a lucky buyer who already had a 100S replica, so I’d better be careful with it.

First impressions are of very quick steering when manoeuvring, and of long transmission gearing suitable for a fast track even though there’s no overdrive here. Exploring the distant reaches of the accelerator pedal reveals an engine of hard-edged eagerness, but it’s still more about torque than revs.

That DB gearbox shifts precisely but won’t be rushed, adding to the authentically vintage feel of the 100S’s dynamics. This is an old-school four-wheel-drifter, springy in its responses as you lean on a balance that’s delightfully adjustable with your accelerator foot. You aim approximately with the steering, and the foot does the rest. Racing the 100S would be endlessly entertaining, and disc brakes all round would let you stay on the pace. That abbreviated windscreen is remarkably effective, too.Contemporary racing footage shows cars drifting all the time; it was simply what the cars did when hurried. Drive the 100S and you’re in your very own Castrol newsreel.

THAT WAS THEN. This is now, and a lot has been learned about speedy Healeys in the intervening six decades. Meet Mike Thorne’s current historic 100M racer (sold since my drive), the most successful four-cylinder ‘Healey 100 racing car in Europe with class wins at the Spa Six Hours, the Le Mans Classic and more. It’s a 1955 car, converted to a racer 12 years ago and recently run by JME, which bought Mike’s Race 100 racing team.

‘The main difference is the engine,’ Chris explains, ‘which has 194bhp – near double the original power.’ The tuning is conventional enough: forged steel crankshaft, race camshaft, aluminium head ported and polished, big SU H8 carburettors with open trumpets – but the magic comes in the way this engine can rev. The tachometer tell-tale says 6900rpm which, given this engine’s massively undersquare bore-stroke ratio and the design’s innate ancientness, is astounding. The intended revs ceiling is 6500rpm.

Other changes include stiffening of the chassis and inner structure (helped by the rollover bar), plus stiffer springs and dampers and an added anti-roll bar. The dampers are still lever-arm units, so visually the chassis looks fairly standard apart from the front disc brakes – Dunlop items were homologated in period. There’s a stronger Sebring straight-cut gear set with molybdenum-coated synchromesh baulk rings, and a competition overdrive with a bigger engagement spring, all taking drive from a skeletal-looking flywheel and a twin-plate racing clutch.
Time to press the starter and fire some sharply defined soundwaves through the hefty exhaust system. This is a racing car, so how will it feel on the road?

I’m sitting low behind a shallow aeroscreen, clamped by a racing harness and clamping a fat-rimmed Moto-Lita, and it feels fabulous. This is a taut-sinewed machine, this modern take on the ‘Healey racer idea riding firmly and cornering flatly as today’s fast cars do. There’s no vintage springiness here. It’s not great on bumps owing to its lowness, but that will trouble it little on a track.

The revelation is its powertrain. With the required revs administered to get past the clutch’s decisive engagement, I can let the engine rip with its astonishing lack of rotational inertia and a crackling response such as can never have occurred to the Austin Atlantic’s engineers even in their most surreal dreams. With only 987 homologated kilogrammes to haul, the engine’s 200lb ft hurls the Healey onwards with a vigour that never seems to end, until a bend gets in the way and I throttle-steer through it. That snappiness of engine response is matched by the quickest, neatest gearchange here (from the loudest gearbox), pedals perfectly positioned for heel-and-toe, and an overdrive so quick to respond that you could almost be driving a modern with a double-clutch transmission.
This is a racing car that works brilliantly on the road, suspension travel apart. A road-trim 100 with this engine would be a captivating machine indeed, something like our already fabulous black-and-red 100M but with an extra dose of chemical stimulant.

MY FOUR-CYLINDER ‘Healey education is complete. These are captivating cars, their design purity a joy, their balance and agility striking compared with the brutish 100-6 (barely faster than its predecessor) and 3000. I’d have one in a heartbeat but, alas, prices have soared beyond my reach so I’ll just live on the memory of my day at The Cape.