HERE and THERE By " Camshaft", August 1930

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De-coking While You Drive.

WHEN one is continually trying out new gadgets, fittings and ideas—generally at the request of their makers or inventors—one is inclined to become a little sceptical over the claims which are always made for them. I must confess I was in this state of mind recently when the Editor commissioned me to carry out a test of the Decarbo Exhalator. This device, as may be gathered from its name, is for the purpose of carbon removal from the engine and the claims made for it are :—It will automatically decarbonise an engine while it is in use, it will cure sticking valves, it will keep plugs and valves clean, and, if used regularly, it will obviate the necessity of decarbonising altogether. The Exhalater consists of a small bellmouthed cylinder into which is fitted a ‘sleeve which, in turn, holds a cartridge containing a chemical compound. The device is fitted somewhere in front of the car—on the bonnet-board, for instance—so that the air, passing over the inner chamber, causes the compound to vapourise. The vapour then passes along a tube to the carburetter intake, and into the engine.

The car to which I fitted it, is some four years did and has not been de-coked for 9,000 miles, and was, therefore, an excellent subject with which to test the claims of the manufacturers of Decarbo. Before putting it into use the head was removed and the condition of the pistons noted. As may be imagined, the carbon deposit was pretty heavy and caused the engine to pink very easily. Since this examination, I have had the device in action for 600 miles, and although I have not yet removed the head, by the improvement in the motor’s running, I am quite prepared to find a definite decrease in the carbon. The engine is far less ” woolly ” than before and the tendency to knock is much less pronounced, so apparently Decarbo is “doing its stuff.” I am to continue the test for another 900 miles, after which the engine will be taken down, and my inspection,

I think, will be interesting.

For ” Spiritualists.”

Hitherto, motorists have been almost entirely concerned with the question of the design and performance of cars. Now, however, that engines have attained to such a uniformly high standard of efficiency, they are turning their criticial minds to the subject of petrol. The sports car owner, in particular, is no longer content to dump any old brand in his tank, and selects his ” juice ” according to his own requirements. Opinions differ greatly as to the most desirable qualities in petrol. Some regard rapid acceleration with high maximum speed as the most important quality of all. Others with very high compression engines plump

for non-pinking and others with an eye to economy think that mileage per gallon is the chief consideration. There are other qualities, however, which a good petrol should possess, such as volatility to ensure quick starting and elasticity in meeting the demands of the accelerator pedal without choking or fuss. At the same time, the spirit should be such that there will be no risk of its thinning the lubricating oil, otherwise serious damage to the engine may result.

Petrol users have now an opportunity to record their views as to the order of merit in which the different properties of petrol should be placed, for the proprietors of the new ” B.P.” petrol are offering £2,000 in cash prizes for opinions on this important question. They have undertaken to contribute to the Prince of Wales’ Personal Fund, for the charitable work of the British Legion, 3d. for every coupon sent in. Full particulars and free entry coupon may be obtained from any ” B.P.” petrol dealer.