MORE HINTS

Sun (Auckland), Volume IV, Issue 1000, 17 June 1930, Page 6

MORE HINTS

The Care of the Car A DECARBONISING HINT When a cylinder head is removed to allow the interior of an engine to be decarbonised, it is important to see that the carbon removed by the scraper does not fall into the cylinders, water jackets, stud holes and so forth. It is a good plan to plug the various holes with rag before the cylinder head and the top of the block are scraped, for in this way time will be saved which would otherwise be spent in clearing the loose carbon from the narrow passages. The rag will also prevent the decarbonising tool from being accidently brought against the polished surface of the interior of the cylinders. USE SAME TYPE OF TYRE It is not advisable to use a non-skid tyre on one rear wheel and a plain tread on the other wheel. It is best to equip both rear wheels the same in order to obtain uniform tyre wear. If one large tyre and one small tyre are used, a different action is set up, which onuses needless wear on it. The tyres on the rear wheels should be of the same size. Different makes of tyres, especially the larger types, sometimes differ in size even though marked the same, while the difference causes a slight differential action when the car is used. PREVENTING THEFT On cars fitted with coil ignition, a simple method of preventing theft is to fit a two-way switch in the lead between the ignition switch and the coil, the extra terminal being wired to the electric horn. The two-way switch is fitted in a concealed position, and when the car is left unattended the switch arm is moved over to the horn circuit. Thus the ignition system is isolated, and when the ignition switch is turned to the “on” position the horn will sound. It is unlikely that a thief will stop to investigate \ the phenomenon! PISTON SLAP A cause of concern and annoyance to owners of cars which have several thousand miles of service to their credit is piston slap. In many modern engines, even tb-ose that are quite new, this noise is most pronounced when the engine is startedfrom cold, but in most cases is not an indication that anything is wrong with the motor which, when it has thoroughly warmed up, is quite silent. Piston slap is due to the clearance between the pistons and cylinders. All metals expand as heat is applied to them, and it follows that to allow a piston to move in a cylinder when both are hot and expanded the piston must be made so that it has a smaller diameter than it actually attains, when it has become hot through work. It is to keep a gas-tight joint at all temperatures that piston rings are fitted. DISC WHEELS Heavy disc wheels of the demountable type can be put on the hub with little exertion if the tool illustrated is used. It consists of pipe and fittings and has a forked end which is slipped under the wheel while the other end serves as a handle. The method of using it is clearly shown. Anyone

who has changed disc wheels will appreciate this helpful tool. After the elbows are screwed on, it is advisable to drill and pin them to prevent movement of the parts when subjected to weight.