"SUN" SERVICE STATION

Sun (Auckland), Volume II, Issue 598, 26 February 1929, Page 6

"SUN" SERVICE STATION

rp£LH ••Motordoru’* section ol The Sun includes in its service to readers a Queries and Answers Department, the object of which is to give accurate information regarding mechanical and touring subjects. Whatever the particular puzzle may be in either diagnosing Irritating troubles, or motoring information of any kind, “Headlight*’ will endeavour to help, or refer the point to men who are recognised automobile experts In their respective lines. All communications must be accompanied by the inquirer's name and address (not for publication), and sent to THE SUN “Service Station, Motordom,” THE SUN. Auckland. Answers will appear weekly In this column.

DD. —To settle an argument, could you please tell me which is the heavier—water or petrol? Water is heavier than petrol—a gallon of water weighs 101 b and a gallon of petrol 81b. W.S.H. —I have an Adler 8 h.p. car. Gould you tell me anything about valve timing and correct settings for choke?

As the Adler car is not on the market either in New Zealand or in England, I’m afraid it would be difficult to help you, but a good mechanic could soon pick up its peculiarities.

D.S.L. —In an engine specification I read recently—l think it was a marine engine —I came across the term "dry sump lubrication.” This has puzzled me ever since, for I cannot see how a sump can be dry.

Dry sump lubrication is employed in motors so u£ed that the oil cannot adequately be cooled if left in the sump. There is a separate oil storage tank connected to the engine by two feed lines. Through one of these, oil is pumped to the crankshaft and through passages or pipes to all bearings, tne overflow from the gudgeon pins lubricating the cylinder w:’ 1 The oil falls to the sump after it is forced past bearings and runs to a well where it is collected and pumped back (by a scavenger pump) to the oil storage tank or reservoir. It may be cooled on the way, by water jackets, before it reaches the reservoir, and is then ready for circulation again. The important difference is that there is no splash lubrication from the sump.

B.E. —I have had a lot of trouble recently over the proper width of my spark-plugs and would be thankful if you could give me some information of a general nature about the proper gap.

Wide plug gaps make an engine hard to start because the comparatively small

spark at low speeds cannot bridge the gap sufficiently strongly to explode partially unvaporised fuel. But wide gaps give a big spark and quicker combustion at high speeds. With the gaps too small the effect is opposite. The spark jumps across easily in starting; but at high speeds a tiny drop of oil or flake of carbon will stop the spark, or the points will become incandescent and spark all the time, firing the charge before it is compressed, and causing a stutter. Get the maker’s setting for your plug points and stick to it. and you should get both easy starting and good running. If the plugs have done more than 8,000 miles, get new ones.