Morris Isis

Introduction

When the Isis was released, the Nuffield organisation emphasised that in developing the Isis - their first six since pre-war - they kept Australia well in mind. And, when judged against other cars available here in Australia at the time, they actually made a very good job of it. The Series I Isis was launched in 1955 as a replacement for the Morris Six MS, and was powered by the BMC 2.6 litre (2639 cc/161 in³) six-cylinder engine C-Series unit from the Austin Westminster, which developed 86 bhp. But, unlike the Westminster, the Isis had a single SU carburettor. The four-speed gearbox had a column change and was available with an optional Borg-Warner overdrive unit.

The Isis was a pleasant car to drive in any conditions, and had versatile performance when punting it from point to point while remaining happy enough to plug steadily along with a caravan behind over a hilly route. It was of adequate five-six passenger size, but compact and handy in traffic. It was of moderate weight, yet more than usually capable of putting up with hard work. It was based on the 4-cylinder Oxford Series II, sharing its almost-unibody shell and torsion bar front suspension. The wheelbase and front end were lengthened to accept the larger straight-6 engine, and a "woody" 2-door estate version was a novelty.

In size and general layout, the Isis closely resembled the Oxford, but the 2.6-litre BMC engine gave it a much more liberal power-weight ratio, which resulted in excellent all-round performance. Judged on similar engines of the era, the BMC six was an admirable engine - quiet, flexible, lively, and sufficiently robust to withstand a considerable power boost if desired. Wolseley, for example, used the same engine in their 6/90 with two carburettors. Maximum power was 86 bhp @ 4250 rpm, with 124 lb-ft torque at the useful speed of 2000 rpm. This brought the best pulling power into speed ranges where it was most likely to be needed.

As to the rest of the car, the excellence of the Morris torsion-bar front suspension had garnered a stellar reputation in the ‘50s. It combined comfort with roadholding and adequate cornering without roll, and the big telescopic dampers fitted fore and aft were quality units up to the rigours of Australia’s poor road surfaces. The four-speed gearbox was well synchronised on the upper three, with accidental engagement of reverse prevented by a pull-knob latch on the column-mounted control lever.

Behind the Wheel

Ratios were well proportioned to engine requirements, with a direct drive of 4.1 -to-one, which gave economical and unfussy cruising. Overall reduction of 13.59-to-one in and 18.4-to-one in reverse gave adequate starting power for the most adverse condition with a caravan in tow. And the Isis was a deft hand when it came to being used as a tow vehicle, thants to its three-quarter-floating rear axle, a type of design to which Morris had been partial even before WW2. It differed from the usual semi-floating design by having the hub bearings ride outside of the housing instead of inside. This meant the housing carried the weight, instead of the driving half-shaft. The latter only had to transmit torque.

The Isis had a pleasant feeling of compactness about it, overall width and overhangs being kept down to a moderate amount relative to the interior space. This, combined with the great flexibility of the engine, made it a nice traffic car. Parking was easy, and third gear (ratio 5.88-to-one) was about right for congested conditions, with lots of acceleration handy to take advantage of an opening. The forward position of the windscreen, however, took a little getting used to, as it brought the pillars into prominence. The seating position was comparatively high and upright – as was the trend in those days – but it provided a comfortable enough driving position and first-rate vision over the low bonnet, with no width-judging difficulties.

Wind noise was low, and dust sealing used double sponge rubber strips which handed the all too frequent unmade road surfaces in country Australia. Equipment included a heater, which could also be used as a forced-draught cold-air ventilator. There were proper instruments, the only signal lights being ignition and top-beam warning lights. The speedo included a trip-mileage indicator. There was also a clock. In those days cars required constant servicing, so accessibility was important. On the Isis it was reasonably good. Hydraulic reservoirs were not fitted on the bulkhead, as in many cars from this time, but were not unduly difficult to reach through the floor. In its favour, this arrangement eliminated piping.

The back seat was curved, very comfortable for two, but possibly a little lacking in support for the stern if three were carried for long distances. There was a centre armrest and elbow rests on the doors. Rear windows could be would right down. The front seat was comfortable for three, obviously it being a bench type. Adjustment worked well, and the latch arrangement was strongly made and easily operated. The Isis had a maximum speed of 90 mph, and at that speed the steering remaining very accurate without too much sensitivity. You could reach around 80 mph easy enough, but you needed to wind up and gather speed to make the last 10 mph. Cruising at 70 was easy enough, without undue vibration nor stress to the BMC engine.

The braking was adequate, with strong pressure required to get maximum result, but fade resistance was satisfactory. The handbrake was typically British average, and was operated via a substantial floor lever, located to the right of the driver. For 1950s Australia the Isis was an excellent highway performer delivering adequate performance with reasonable fuel economy. It was well enough engineered too, as evidenced by the location of the fuel pump, which was at the rear near the tank, thus almost eliminating the risk of vapour lock from engine heat – a common complaint on cars at the time. At launch in Australia the price of the Isis was £1335 14 6. including purchase tax (list price. £1070). Unlike its sister car the Austin Westminster, which enjoyed moderate success against the volume-selling Ford and Vauxhall sixes of the time, sales were poor, with just 8,500 sold.

Morris Isis Series II

The Morris Isis Series II was based on the Morris Oxford Series III body but with longer wheelbase and front wings & bonnet to accommodate the 6-cylinder engine. In line with changes to the corresponding Oxford line, BMC redesigned the Isis for 1956 with updated styling including a more elaborate mesh grille, chrome side strips and small fins. The engine power increased to 90 bhp. An automatic transmission option was also added. The manual version had a four-speed box operated by a short gearstick located on the right-hand side of the front bench seat.

The handbrake lever was located just behind the gearstick. Sales remained weak, and the line ended in 1958. A de luxe saloon with overdrive tested by the British magazine The Motor in 1956 had a top speed of 90 mph (140 km/h) and could accelerate from 0-60 mph (97 km/h) in 17.6 seconds. A fuel consumption of 26.2 miles per imperial gallon (10.8 litres/100 km; 21.8 mpg-US) was recorded. The test car cost UK£1025 including taxes. The overdrive unit had added UK£63 to the price.