Most of the time I write about new technology, and sometimes of its failings, so in a request from our esteemed editor, this one is very different. It compares two vehicles I’ve owned – a QL Bedford made in 1943, and owned from 1956 until 1962, and a 1994 OKA owned from 1996 until 2006.

The QL was designed as a multipurpose 3277 kg (plus 3700 kg payload) four-wheel-drive chassis for UK military use. Mine was the relatively rare QLR model that had been set up as an RAF mobile air control centre. It had a superbly-made (by Mulliner) coach-built body, plus a huge (550 watt) dynamo driven permanently from the transfer gearbox.

I was working at the time in the Vauxhall-Bedford Research Centre in the UK, with a particular interest in vehicle suspension, and sought to establish the range of surface conditions across Africa. The director rapidly and correctly worked out that was simply a justification for my wanting to drive around Africa anyway, but while declining GM’s part in it, helped to persuade Mobil to supply fuel, service facilities and political assistance the whole way. The almost unused QLR was bought for £100.

As the intent was to take it twice the length and breadth of Africa it needed a fuel range of 2500 km. This necessitated 1100 litres in desert going, and enabled an extraordinary 4500 km on road! On the return journey, refuelling in Gibraltar enabled us to get back to London via a detour to Monaco to watch the Grand Prix – and then back to London via the French Alps.

We also needed to carry 500 litres of water, sufficient water for myself and (initially) two companions. So, what with close to 800 kg of fuel, plus 500 kg of water plus the weight of the tanks, spare drive shafts, and all that needed to pull the thing apart if necessary, plus a body that weighed more than 2000 kg the rig  was well and truly at its limits when fully tanked up. Fortunately the 1100 x 20 16-ply tyres could readily cope. Each was rated at more than 6000 kg!

Sahara bogged (Touareg helping). I ‘supervised’!

All this was hauled by a Bedford version of the Chevrolet overhead valve six-cylinder engine that originated in 1932. It developed a mere 72 hp (54 kW) so had a rarely reached maximum speed of 60 km/h. Its low-range bottom gear ratio of 102:1, however, enabled it to climb gradients (at less than 1 km/h in low-range first) that our 1994 0KA could only dream about. It had huge pulling power and on its return Sahara crossing towed almost seven tonnes of a forward-control Jeep across much of it often in soft sand (a total of more than 13 tonnes).

Home via the French and Italian Alps

It initially burned out exhaust valves every 10,000 km, once necessitating removing the cylinder head in mid- Sahara to grind them back to shape. Assuming the cause to be a faulty radiator cap that was losing pressure, causing water cavitations around that part of the cylinder head, we inserted a spare Schrader valve in the radiator cap, and added pressure once the engine came up to temperature. This fixed the problem. Apart from that, not a single thing went wrong, but the QLR was in need of an engine and suspension rebuild after that almost all off-road 75,000 km. My companion throughout that epic trip (that included driving through Algeria at the height of the war for independence) was  Tony Fleming, who went on to found Fleming Yachts now recognised as the very best ocean-going motor yacht in the world.

Seven tonnes of hesitancy

THE OKA

The OKA, had it been properly developed, could and should have been the QL’s successor. Like the QL it was made in various forms: ours had a coach type body for transporting miners in a coal-mining environment and covered some hard 50,000 km of that prior to purchase. It was almost exactly the same width, length and unladen weight of the QL, but at a maximum gross on-road mass of 5500 kg, the coach-built OKAs had a payload of only 1500 kg or so. They could, however, be upgraded to 6500 kg (many were) but this reduced their offroad performance.

Assessing ships of the desert

Knowing just how vital is to minimise weight off-road, we had the interior built almost entirely from white powder-coated aluminium (under 75 kg in total). Even with twin 120-litre tanks and 140 litres of water, twin spares and a 1200 kg pull winch it weighed only 5200 kg on-road (many conversions are known to be over seven tonnes).

Exiting the Sahara, and still 1000km of desert to go!

As with the QL, all but a few OKAs are powered by an engine that also originated in the early 1930s. It is the turbo-charged MT version of the 4.0-litre Perkins Phaser. It develops only 110 (82 kW) but has huge low-end torque. Ours returned  a typical 12-14L/100 km so its twin 110 litre tanks provided about 2000 km range. It could cruise comfortably at 100 km/h but, even at that 5.2 tonne, had much the same hill-climbing speed as a fully-laden B-double. Suspension-wise it was very similar to the QL with long leaf springs and again, as with the QL, the original shock absorbers were barely adequate.

The QL cylinder off (in Algeria) for fitting new exhaust valves

OKA owner experience varies but initial buyers of the 500 or so made had problems. Most have long since been sorted out but failings extended from a dreadful Lucas (Prince of Darkness) direct-drive starter motor, those totally inadequate single front shock absorbers, cracking and bending of U-bolt axle mountings, half-shaft breakage and major transfer box issues in later models, due to boxes (made for a totally different purpose) lacking thrust bearings. Ours had some of that, once necessitating an epic 600 km in front-wheel drive alone when a half-shaft broke.

Photo: Paul Crompton

That reducing tyre pressures assists hugely in sand has been known for a long time (among other information such as how to feed and control yaks) it is recommended in the Royal Geographical Society’s 1932 edition of its wonderful Hints to Travellers, but the QL’s huge tyres needed only marginal pressure reduction and very occasional sand shovelling, so despite soft patches of often 100 kilometres across, there was never a real problem.

The OKA copes well too, given low enough pressures, but in my opinion really needed far stronger transmission and larger diameter tyres than the preferred original 900 by 16s (and later, but low-profile 19.5 inch). The company did offer 1100 by 16 as an option but that further increased torsional stress on already barely adequate half-shafts.

Once sorted, however, an OKA is (or at least ours was) almost astonishingly reliable. Ours, originally registered as OKA 002, subsequently took us across Australia from Broome to NSW and back 12 times with never a single failure. It comfortably covered 800-900 km a day on almost none but dirt tracks. It is a tragedy that it came so close to being a commercial success and has no spiritual successor. Many, in the hands of tour operators have done well over a million kilometres, but the OKA has become virtually a collector’s item. Most are now privately owned and some fetch more than $100,000.

OKA bogged near Broome

The QL ended its days with a demonstrably disdainful Rolls-Royce chauffeur who shunted grouse-shooting aristocrats around the owner’s vast country property. The OKA was sold to  CMCA member Paul Crompton in 2007 – who has since restored it to literally concourse condition.

The major difference was that while the QL had been well designed and developed, the OKA designers, who were seeking a mining market, were seemingly unaware that it was not customary for development to be based on what goes wrong for the first 100 or so owners: in this case, for about a fifth of the 500 or so made. Changes were made almost from unit to unit. It is unusual, for example, to see two OKAs pre model numbers 250 that have exactly the same U-bolt axle clamping plates.

The company ceased producing the originals in 2010 or so, then produced about 15 ‘NT’ models reported as  meeting military specifications. They have Cummins engines, much stronger transmission and 20-inch wheels. It then ceased business but is currently said to be in ‘a state of suspended animation’ (whatever that means). Had it stayed in business it would eventually have been a superb unit. This may yet happen as, realising the basic concept really was good, a move is under way, by privately owned OKA Parts Australia, for them to be rebuilt almost from chassis up with bigger engines and transmission – all OKAs have huge disc brakes so that side is fine. The closest equivalent today is probably the Mitsubishi Canter. However, like many modern vehicles that seem ultra-competent, it somehow lacks character.

OKA crossing Wenlock River

Category: Technology
Written: Sun 01 June 2014
Printed: June, 2014
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