“SUN” SERVICE STATION

Sun (Auckland), Volume II, Issue 462, 18 September 1928, Page 6

“SUN” SERVICE STATION

rTVHE ’Motordom' 1 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 All communications must be accompanied by the inquirer's name and address (not for publication), and sent to THE SUN “Service Station, Motordom,” THE SUN, Auckland.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.

J.R.C.—I have a 1927 Hudson Brougham, and want to know how many miles it will go wide open, and how fast, without injury to the motor, when properly broken in. Maximum speed 84 ’m.p.li., otherwise 60 m.p.h. M.C.D.—The oil gauge of my MorrisCowley is troublesome. The car is a 1927 model, and has done 4,000 miles. The hand of the oil gauge travels right round the dial, according to use of accelerator, when starting any morning, but when the engine is warmed up and car running under normal conditions the gauge does not register any pressure at all. This condition obtains both with tihe use of Castrol “XI” and Mobiloil lubricating oils. i- * * * The trouble is caused either through a faulty oil gauge, the relief valve in the pump not seating correctly, or the main bearings are worn to such an extent as to allow the oil to bleed too freely when it is hot. The Morris engines are forced fed lubrication to the main bearings, and splash fed to the connecting rod, pistons and gudgeons. The feed to the connecting rods, etc., is obtained through channels cut in the main bearings. M.F.—I have a 3,925 Master Six Buick and it seems to run fine when the motor is cool, but when the motometer gets the red up to the circle or summer heat, the motor seems to hesitate, then go ahead, sort of kicks back and goes ahead as if the gas shuts off for a second and gains on the motor — will not stop, only you can feel the car jerk back and go ahead. I nave had the valves just ground, carburettor and vacuum tank cleaned, a new lead wire and new condenser put in; but it did not remedy it. I have taken it to several Buick authorised shops and they have done it no good. It will run fine while the motor is cool, but just as soon as it gets warmed up it will begin to jerk, just as if it was shooting out of time. The motor does not overheat. * * * Your trouble is in the carburettor.

Have a competent mechanic look it over. J.McD.—The carburettor of my car floods very often when it is standing on a side slope, and as petrol turns to vapour there must be a fair amount of gas under the bonnet, because the tray is quite wet with - 'trol. In view of this, is there any dangt. of a fire being started by the generator, which is fairly close to the carburettor and must have explosive gas around it? As cars sometimes catch fire, could this be the reason, and can you inform me if it is wise to take any precautions? * * * As long as the inspection cover of the generator is firmly secured there is no chance of the slight spark of the brushes on the commutator igniting petrol vapour. At the same time, it is as well to be careful if you are cleaning the commutator with the motor running that the carburettor does not flod then, for the sparks are capable of ignition. The wisest precaution would be to grind in the needle valve of your carburettor to a better seating and stop the flooding, or to turn off the petrol every time you leave the car standing on a slope. C.R.L. —I am worried by a peculiar knock which comes from under the floorboards of my car when I am travelling over rough roads. It sounds as though something had shaken loose, but not in the engine. I have tightened up the body bolts, and the battery is firm and the tray is not loose, so I wondered if you could suggest what might be the cause of the noise. * * m It sounds to me as though your knock is in the universal joint. This will happen when the pinions are worn and is caused by backlash in the drive. Have a look at these, and if the trouble is not there, get a good mechanic to examine the jaws of the dog-clutch which engages top-gear in the gearbox. Some of the noise might come from there, too. If they are worn, have them renewed.' It should not be very expensive.