Jowett Jupiter






By Mike Chambers



























" The Yorkshire Porsche " 

Was the Jowett Jupiter the best 1.5 litre sports car of it's day [1950], with a front engined horizontal opposed flat four, Tubular chassis and aluminium body.

Racing success seems to put it right up the top, But where did it all start.

Jowett's were a Yorkshire firm and began by making engines in the early 1900's, moving on to produce cars in 1910 with a style of small rugged car that would see them through to 1953. All powered by flat twin horizontal opposed water cooled 4cylinder engine with overhead valves a cast Aluminium block, wet liners cast iron cylinder heads and a 3 bearing crankshaft.

1910 was this before the air cooled engine of Hr Porsche if so did he do some coping from Jowett " Come on some one out there take up the challenge and tell the Beetle story


Back to Jowett's, They managed to survive the two world wars and emerged after W W 2 to continue production of cars under the direction of Calcott Reilly who took over the company from the Jowett brothers when they retired just before the start of W W 2. He planed to produce a new car in 1942 with production to start when hostilities finished.


To help him in the design he hired in Gerald Palmer from M.G. the result was the extremely advanced Javelin announced in 1947 , Which received rave reviews from the motoring press but with some traumatic problems behind the scenes.

The engine is a high compression version of the flat-four engine from the Javelin and is sits ahead of the front wheel centre line. The engine can be removed in 20-minutes but keeping water off the sparking plugs can be a problem.




















To increase their "steel" allocation Jowett decided to produce a sports car on the Javelin and to help this along Javelins managed class wins in the Monte Carlo Rally and Spa 24 hr Race where a standard Javelin covered 1,700 miles at 65.5 mph average [Not bad for 1949] .

Once again to help with the design of the new sports car Jowett imported top class assistance, Professor Robert Eberan Von Eberhorstone one of the best chassis designers (He designed the chassis for the 1938-39 Auto Union Grand Prix cars) and the services of ERA. LTD ( Of ERA racing car fame ).

Eberhorst was presented with a design which centred around the Javelin torsion bar suspension and running gear, with the engine mounted ahead of the front wheel centre line, the resulting chassis was a simple tubular structure.

On which Reg Korner of Jowett's designed an all aluminium body adding only one steel section,in the form of a front bulkhead.

Some dissension started to arise as ERA disliked the body shape and Jowett's were non to happy with the chassis bending in the centre, this was stiffened up and ERA parted company with Jowett's so the Jupiter was born.




















The engine was the Javelin 1486 cc unit with it's compression ratio increased from 7.2-1 to 7.6-1 and twin Zenith carburettors thus raising the brake horse power from 50 to 60.






















The twin carb unit


With the car weighing in at aprox 17 1/2 cwt ( Now I have a problem, 1 Hundred weight [cwt]=112lbs & 20cwts=1ton, so what's it weigh in metric units 889.056 kilo grams. Does not have the same ring to it as 17 1/2 hundred weight ).

When the Jupiter appeared in the 1950 Motor Show people were surprised by this striking advanced car but it had some fearsome competition in the form of Jaguar who 1948 had introduced the 3.4 litre XK120 and in 1949 it went on sale priced £1263, The Jupiter was a fraction cheaper at £1086 but still expensive never the less it impressed the motoring press and had successes in competition and how much faster was the 3400cc Jaguar against the Jowett's 90+ mph on 1486cc.

Rumours abounded on the unreliability which had fact behind them, in that raising the compression ratio and low octane fuel of the time caused cylinder head gasket sealing problems and the occasional crankshaft breakage but Jowett did over come all these troubles as there competition success showed.

The Jupiter managed class wins at Le Mans at an average speed of 75.84 mph and at the Monte Carlo Rally, So it was no slow coach.


















The dash as seen above ensured the Jupiter driver was never bored as the car is fully instrumented so a newcomer is likely to become confused with all the dials in front of him. For a car that was active in completion the steering column gear change was a most unusual feature but was extremely well engineered and easy to use. Earley Jupiters had a wooden dash.

Well what's the car like to own and drive ( I have to resort to hearsay now ) the engine will start promptly and rev upto 4500 RPM, Gear changing needs getting used to as it's a left hand steering column change but it's a first class one as shown by it's competition success, The front seat is a bench type with not to much adjustment ,if any, The peddles are a bit strange to with the clutch well to the centre of the car and the brake and throttle close together on the other side, Steering is quite light for a car of it's time especially considering 55% of the cars weight is over the front wheels which means the tail end can slide out being so light but once used to it can be driven fast, how about stopping well brakes were drum all round with hydraulics by Girling

Now comes the down side if you want to own one, first under 900 were built, and the cruncher the aluminium body panels were made on rubber dies then hand fitted to each car in the works, so they are not interchangeable at all.


All The Best Folks