Sir,

From time to time in your magazine you have expressed the opinion that it should be possible to produce a car which would cruise at 60 m.p.h. and 60 m.p.g. I was interested in this possibility because I was running an MG-B which was costing about £1 per day in petrol to run. This would not have distressed me so much but for the fact that the petrol revenue was feeding the tax-collecting machine which was causing the embarrassment in the first place.

However, to the point. I carried out certain modifications to the MG which included fitting fuel injection, increasing the compression ratio somewhat (to 23 : 1) and various detail changes which I will not bore you with. The car now has a top speed of around 75 m.p.h. and over the past 25,000 miles has never returned less than 50 m.p.g., whether cruising at 60 m.p.h. or in around-town motoring. The car is, in fact, fitted with a 1,500 c.c. diesel engine. As would be expected with an engine of this type, there is an increase in noise, which emanates from two sources, combustion “knock” and injector “tick”. The former is familiar to anyone who has heard a London Taxi and is noticed more when the engine is idling than when one is under way, and the latter, caused by the injector needles being forced off their seating by the shot of fuel at a pressure of about 2,000 psi., sounds like tappet noise. I have not carried out any sound-proofing on the car because I haven’t found the noise level to be high enough to be troublesome, but normal sound-proofing techniques seem to work quite well, particularly in reducing the injector “tick”.

Early morning starting is easier than with a petrol engine, and even when it has been standing out all night covered in snow it will start every time in about five seconds. As soon as it is running it is possible to drive off as there is no choke or other control to fiddle with. The battery has not so far suffered from the higher starting current and no change was necessary to the battery rating or to the charging circuit, but I did fit thicker starter motor leads as the cable run is very long in the MG-B (the battery is in the back).

Performance is, of course, reduced, but where I live the traffic is so dense 90% of the time that this doesn’t matter too much. I haven’t taken any acceleration figures, but the car seems to fare quite well against the average family saloon, and, of course (like D.S.J.), I still have open-air motoring. As for handling, this doesn’t appear to have changed at all, although I have to wait until it snows before I can prod the tail out ! The engine is somewhat heavier than the petrol version, this increase being attributable in the main to the flywheel, starter motor and injector equipment. I have endeavoured to offset this by removing various items, including the vast casting which is the exhaust manifold on the MG, also the front silencer and, of course, the carburettors.

Various amusing incidents occur from time to time with this car. For instance, there was the AA man who wanted me to join until he heard the “big-end knock”. On another occasion there was the garage which got so used to filling up my red MG-B with diesel fuel that he didn’t query the man in a similar car when he pulled up near the derv pump, and promptly squirted six gallons of the evil liquid into the poor unfortunate’s tank. Altogether it has been an amusing and instructive exercise and has convinced me that the 60 m.p.h. and 60 m.p.g. landmark is feasible with a bit of development work (which diesels haven’t seen—unlike the racing influence on petrol engines) the diesel could become a force to be reckoned with in the domestic car market.

D. CONNING – Rayleigh