PROJECT DP208: THE VOLVO-ASTON
John Simister drives a unique Volvo with a four-cylinder Aston engine
AVolvo in Vantage? Well, Aston Martin and Volvo were bedfellows in Ford’s Premier Automotive Group not so long ago, and before that there were tenuous connections via TWR. But what you see here is something else altogether, something that dates right back to 1961.
It’s Aston Martin project DP208. At least, part of it is, and originally the whole of DP208 looked just like this. See the bulge in the bonnet? That’s because there’s too much engine for the space originally intended for one. Were this a Volvo production car, as was once the tentative intention, it might have been called the Volvo P2500. Instead history and finance got in the way.
The engine might look familiar to the Aston-fancier, yet strangely abbreviated. That’s because it is effectively two-thirds of a DB4 engine, a meaty, muscular twin-cam four-pot of a little under 2.5 litres. It uses as many of the DB4 engine’s components as possible and shares its 92mm bore and stroke, so it’s odd that Aston quoted the new engine’s capacity as 2499cc. Actually, at two thirds of the DB4’S 3670cc, its cylinders amount to 2447cc.
But that’s detail quibbling. Much more important is the key question: why does the engine exist? Because Aston Martin thought there could be money to be made by selling engines to other car companies: smaller, more-affordable engines that nevertheless carried the Aston Martin cachet. First, though, trial engines had to be built to check that the design worked, after which one would need to be tried out in a suitable car.
Ever strapped for cash, Aston Martin allocated just £3000 to the project. Engine designer Tadek Marek created a new block and head rather than cutting and re-welding DB4 components, plus a new five-bearing crankshaft and suitably phased camshafts, but the design philosophy was carried over along with whatever DB4 components could be incorporated. Work began on March 9, 1961, and on July 29, 1963, one of the three completed engines was installed in a Volvo P1800.
Why the Volvo? That was the suggestion of Charles Singer, whose Lex Group was not only an Aston Martin dealer but Volvo’s British importer. The engine was duly squeezed into what became DP208, and the combination worked well enough that, after testing, it became Mrs Marek’s daily driver. The business case, however, was less convincing. So labour-intensive would the engine be to build, judging by experience with the sixcylinder version, that selling it at a price low enough for those likely to use it would be impossible. The project duly died, Mrs Marek had to surrender her Volvo-aston and that was that.
What happened to the Volvo is unknown, apart from the fact that it had its Volvo heart reinstated. All three engines seemingly went to ground, too, until one resurfaced in the 1970s, as reported by Jonathan Wood in a 1974 edition of Classic and sportscar. Aston specialist Richard Williams remembered owning one of them, which he sold to Aston enthusiast Craig Dent. Robin Hamilton, famous Aston racer and specialist, later bought a fourcylinder, Db4-derived engine from Dent and it was this unit – likely the one that Williams had owned – that Wood spotted in Hamilton’s workshop and which prompted the article. Hamilton later used it in a race car.
In that magazine article, Wood also talks of the subsequent conversation he had with Aston Martin’s engineering chief during the DB4 era, Harold Beach, who said that the original wooden patterns for the DB4’S block and head castings were getting ‘a bit ropey’. So there was no objection to cutting them down to create the patterns for the four-cylinder engine, in the process saving the cost of creating new patterns.
The new engine, fed by a pair of massive Weber 50DCOES, reportedly worked well, but it put an extra 30kg over the front wheels despite its aluminium construction. That made the steering very heavy, so a production version of the Volvo-aston would have needed some development here. That never happened, and the existence of a four-cylinder Marek engine gradually faded out of memory apart from that brief reemergence in the 1970s. Until now.
Swiss Aston specialist Beat Roos, of Roos Engineering fame, came by the ex-williams/dent/hamilton engine in Cologne, Germany, in 1998. Three thousand Deutschmarks later, it was his, and he had a plan. Which was nothing less than to recreate DP208 as accurately as he could.
First, he had to find a suitable P1800. Early examples were built in Britain by Jensen on Volvo’s behalf, using bodyshells made by Pressed Steel in Linwood, across the road from where the Hillman Imp factory was under construction, and Beat’s 1961 P1800 is one such car. ‘We started work in 2001,’ he recalls. ‘To get the engine to fit we had to modify the steering, so instead of the steering box there’s a rack from a Triumph TR4. We made new engine mountings and of course the bonnet bulge. As standard, the Volvo engine is tilted back a bit, but this one is tilted a little more.’
Other changes included dual-circuit brakes, for wise reasons of safety, and the clutch is a Laycock diaphragm-spring unit – a new design in the early 1960s – with hefty 9in-diameter plates. ‘We made a special radiator and oil cooler,’ says Beat, ‘and we used a shortened DB4 airbox because that’s what Aston Martin would have used.’ Also from a DB4 is the separate header tank for the cooling system, needed because the top of the radiator is below the highest point of the water’s flow.
As for the engine, it didn’t run at all well on the 50DCOE carburettors. So Beat abandoned that piece of history and tried genuine 1960s 45DCOE9S as fitted to a DB4 Zagato. He started with the jets and choke sizes recommended for the Zagato by Ted Cutting, Aston Martin’s famous racing engineer, but, says Beat, ‘The result was quite bad. What we’ve ended up with is very different from any DB4 settings.’
Maybe that’s something to do with intake and exhaust resonances, firing orders… who knows? As an aside, the DP208 engine uses an unusual firing order of 1-2-4-3, rather than the 1-34-2 of most in-line four-cylinder engines. Why is hard to say; even in the early 1960s that firing order was largely discredited because it concentrates loads sequentially at one end of the engine and then the other, instead of distributing them equally, although Ford’s contemporary straight-fours also fired 1-2-4-3.
Beat’s early dynamometer tests of the engine, once rebuilt, produced less power than Aston Martin recorded back in the day, one run recording 132bhp at 4998rpm and 143lb ft of torque at 4501rpm. However, with the carburettor settings sorted out, it peaked at a healthy 148bhp and 5497rpm, at which speed it was also producing a muscular 142lb ft. That suggests a peaky power delivery, but actually the torque curve proved quite flat with 138.5lb ft available at 3500rpm and 134.5lb ft at 3000rpm.
Thus optimised, the engine was installed in the Volvo and the completed car made its public debut in 2005. Since then, Beat has enjoyed using it often. And now it’s our turn.
APART FROM THE BULGE and the Minilite wheels, shod with generously broad 185/70 HR15 Vredestein Sprint Classic tyres, this not-p1800 looks much as you would expect a beautifully restored example of Volvo’s very pretty coupé to look. Examine it more closely, though, and there’s a giveaway to what lies within: badges proclaiming ‘Powered by Aston Martin’ adorn each side of the bonnet bulge.
With that bonnet open, I can see how the Aston twin-cam is almost bursting out of its bay. Beat points out the cam-cover retaining nuts, arranged singly as in a DB4 rather than the pairs used in later Marek straight-sixes, and I also spot the modern 123 distributor with its electronic ignition map. Down below is a typically-marek large sump, here containing eight litres of oil.
I start the engine. It’s rorty and snorty in characteristic twin-cam, onechoke-per-cylinder fashion, gobbling
away like a big Alfa or Lotus twin-cam: hard to reconcile with the Volvo shape and the gentler note that usually emerges from it. We’re heading for the hills beyond Roos’ Safenwil base, the weather is not looking promising and, goodness me, this steering is seriously heavy. Mrs Marek must have developed impressive shoulder muscles back in 1963 although, to be fair, her version of the Volvo wouldn’t have had such broad tyre treads as this one has. (The original also wore wire wheels, incidentally.)
As soon as DP208/2 (as we can unofficially call it) is moving, all that changes. The steering becomes surprisingly light, even more so as the perforated-spoke wheel is turned far off-centre, at which point it does that old-volvo, geometry-related thing of ‘wrapping on’ – pulling itself onto lock instead of requiring effort from the driver. As we venture into the countryside, it’s clear that the shift of the standard Volvo gearbox is quite stiff, the ride over bumps is really rather good and the heater is extremely efficient, as a Swedish heater should be.
All that is down to the Volvo part of DP208/2. The view past the bonnet bulge, and the sounds and foot-pounds emerging from beneath it, are Aston Martin’s doing. I’m driving what feels like a Volvo hot rod, a touch lugubrious in the corners thanks to that added nose weight but crisp both under the accelerator foot and to the ears. Loud, too; the engine mounting rubbers are clearly hard, given the booms and vibrations finding their way into the cabin. A production version would have had to be better here; as well as that carburettor data, Beat’s conversation with Ted Cutting revealed that the vibration (perhaps connected with that firing order?) was one reason why the project was dropped.
Yes, yes, but how well does it go? Is this a kind of primordial Porsche 944, a lusty front-engined coupé with a big heart and big bangs from four big cylinders? That’s exactly what it is. Pace up hills is a bit less enthusiastic than I would expect from 148bhp, but on the flat the Volvo lopes along keenly – the overdrive helps lengthen the legs – and the ample torque makes for a relaxed, continent-munching drive.
And now it’s snowing. I’m driving the only Marek-designed four-cylinder prototype engine known to have survived, in a car semi-uniquely adapted to house it, and I could slide off the road any minute. Luckily the steering is both precise and informative of the state of grip under the non-winter tyres, so I just have to tread carefully and keep a space between us and the other traffic.
There’s nothing like a sense of jeopardy to help you bond with a car. What a shame that Aston Martin and Volvo decided not to build more. And where, we wonder, are the other two engines?
‘AMPLE TORQUE MAKES FOR A RELAXED, CONTINENT-MUNCHING DRIVE’
Prestige Paintworks pride themselves in being experts in high-end automotive restoration. Their commitment to excellence and high standard workmanship is apparent in all work they do, gaining them a reputation in the industry as the ‘go-to’ company for restorative, refinish and fabrication work. Past projects include a 1955 XK 140 OTS body off restoration, a Series 1 XKE roadster for a local E Type specialist, a 1972 Aston Martin DBS for a body off body and paintwork restoration, a 1955 Aston Martin DB 2/4 Mk1 Drophead for a body off body and paintwork restoration to concours.
Current projects are an Aston Martin DB5 colour change to Silver Birch, a 1958 Aston Martin DB Mk3 Drophead complete nut and bolt restoration to concours, a Series 3 XKE for a concours nut and bolt restoration and a 1973 Ferrari Daytona for a major exterior body and paintwork restoration.
Clockwise from top Simister finds out what a four-cylinder Tadek Marek engine feels like. Big on torque – and rather loud – is the answer. The 2.5-litre unit sits at quite an angle in the P1800’s engine bay, which necessitated the bonnet bulge; early P1800s were actually built in Britain, by the Jensen sports car company
Opposite and above Facia and controls are all standard P1800. Steering requires quite a bit of hefting around – extra weight of Aston engine really makes its presence felt at parking speeds. On the move it’s much better – precise and informative, which is just as well when you encounter very Swedish weather condtions
A fabulous 1969 Aston Martin DB6 Volante recently restored by ourselves for a body and paintwork restoration including extensive structural corrosion issues, due to be exhibited at the Hampton Court Palace Concours of Elegance in its original colour Amethyst.