“SUN” SERVICE STATION

Sun (Auckland), Volume II, Issue 396, 3 July 1928, Page 6

“SUN” SERVICE STATION

fIIHE “Motordom” section of 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 All communications must be accompanied by the inquirer’s name and address (not for publication), and sent to THE SUN “Service Station, Motordom,” THE SUN, Auckland.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.

WHAT DOES BATTERY DO? W.H.T.—Being smitten by a decision to give my battery plenty of attention now that the winter is coming, I would like you to explain how much the battery is affected at night when the lamps are on and the engine is running. Is there much drain on its power under these circumstances? * m * The ammeter of your car will tell you how much work the battery is doing at any time. If your generator is clean and in good order, it should supply sufficient power to satisfy the demands of the lamps when travelling at anything better than 15 miles an hour. If t.he generator output is more current than the lamps require, that fact V7ill be reflected in the ammeter, which will show the amount of the surplus on the “charge” side. And if your car speed is too low to allow the generator to supply enough power then the battery makes good the deficit, and the discharge taking place. If there is a surplus from the generator, the battery absorbs it, if a shortage, the battery supplies it. ENGINE BOILS EASILY D.L.C.—Wall a weak mixture make a car boil very easily? I have been told by a friend thatt this is the cause of my trouble, but I £e>ar it may be something more serious. It has done about 4,000 miles, has never been touched nor altered, except uhat I have reset the carburettor. If I have to use second gear for even a cv>uple of minutes the radiator steams violently. Do you think carbon in the engine might catise this? There is no knock fj\om the motor, and the average running* seems good except for the overheating. * * * I think your trouble is probably a combination of weak mfveture and carbon. The fact that the* engine does not knock, and has not decarbonised after 4,000 miles running, supports that idea. If a mixture is thinned too much it burns too slowly to .give much power, while more heat is parsed on to the water-cooling system. A knock is caused—when an engine needas cleaning—by the carbon deposit being rendered incandescent and exploding the mixture before compression is complete. You can see that, if the mixture is too weak, it will stand greater compression before explosion, and then will burn so slowly that there is little resistance or impact on the rising pistons. The remedy should be to have your heads cleaned and valves ground, and don’t starve the engine. H.R.O.—Lately I have found trouble with my top gear. That is, the lever jumps out of engagement and into neutral when I am travelling in top gear. The car is about 18 months old and has done about 10,000 miles. * * * I had similar trouble with my gear box about a year ago, but it was second gear which would not stay put. I tried tinkering around with it myself and found that the dogs had worn—tapered off —so much that they could not carry the load when the car was being driven, and were forced out. I took my bus to the dealer’s service station, and they fixed it without much cost. Since then it has been absolutely O.K. I suggest you do the same and save yourself some worry. CLEANING COOLING SYSTEM J»T.D.—I have tested almost every part of my engine to discover why it i 6 overheating, and have come to the conclusion that it is the cores of the radiator, and water jacket must be clogged up. Can you recommend a safe cleaning compound? I have found that weak solutions of soda or ammoniac poured into the

radiator, and changed four times in 500 miles running, -cleans the radiator well. After changing each solution, flush the cooling system out with a hose: this removes the muck which the solution loosens. I have not tried the manufactured compounds. CLUTCH DRAG R.A.—The clutch on my car (a single-plate clutch) keeps dragging, and I cannot remedy the trouble. I have washed it out with kerosene and put in a mixture of kerosene and engine oil, instead of pure oil. but this does not cure it. The clutch plate should be in good condition, as it was relined a little while ago. I would be grateful for a suggested remedy. If, as you say, the plate of your clutch was re-lined recently, you may be experiencing the trouble I once liad with a dragging clutch. I found, after trying all the remedies, that the new lining was too thick. The result of this, of course, is obviuos, as the plates cannot be shifted sufficiently to free themselves. Have the lining examined by somebody competent to judge. HEADLAMP DIMS G.B.—What would cause a headlight bulb to become more dull than its mate? The right-hand lamp of my car is almost yellow, and the left-hand white, and when I change the bulbs over the bright one goes dim and the dim one becomes bright. That should mean that the bulbs are all right, but I cannot understand why one side of the car should get more power than the other. The fault in your right-hand headlight may be a faulty connection at the terminal screw in » the light holder, which would prevent all the power from getting through to the bulb. Or it may be that the bulb is not making proper contact with the base of the holder, due to the spring plunger lacking tension. I would look for the trouble in these places first. It is possible, too, that the wire may be rubbed bare, or broken inside its insulation somewhere. I have found them like that inside the lamp cover, at the back of the holder. Wires which have been forced into a bent position lor some time are liable to break internally under the pressure. NOISY BRAKE DRUM “Worried.’'—Would you please tell me the cause of one brake being noisy and the other one quiet? The righthand brake of my car makes a hammering noise on the drum whenever I push the footbrake pedal, while the left-hand one works all right. The right one also jambs, and can be released only by jerking the pedal. The hand-brake is not affected at all. I relined the brakes myself a little while ago, this hammering noise has just developed. It happens even when the pedal is touched very lightly, and when I put iX on hard there is a terrible row. I have .looked at the brake drum and that seoms all right, and the lining looks just the same as the fabric on the left-hand brake. If “Worried” will look at his brake linings again, I think he will discover that the lining on the shoe of the brake which is noisy is longer than that of the efficient shoe. If that is so, it means that the eends of the lining are hitting the drum sooner than they should; that is, before or at the same time as the centre of the shoe, and this will cause tlie trouble. I write from a similar experience. The remedy is to get a rasp and bevel off the ends of the lining: that is, file them down in a slight grade until they merge into the metal of the shoe itself. This will allow the brake to function properly.

A lot of vacuum tank trouble can be attributed to sediment in the motor spirit. A little dirt will clog a valve and cause a tie-up on the road, so *t is a matter of double protection to filter the spirit before it reaches the tank by fitting a special visible filter. If sou start with a clean tank and » clean fuel line from the tank to the carburettor a second filter may not be necessary but as an extra safeguard it is worth using.