“SUN” SERVICE STATION

Sun (Auckland), Volume II, Issue 504, 6 November 1928, Page 6

“SUN” SERVICE STATION

r PIIU Motordom” section of The Sun includes in its service to readers a „ an<3 Answers Department, the object ot which is to give lnfo 'j m atiori regarding mechanical and touring subjects WhatoremnmriT^ T n!s U,ar suzzle#5 uzzle # ma y *?e in either diagnosing Irritating troubles, “ r ,™ O VT nS tn f° r m atl °n of any kind. Headlight” will endeavour to help, or retirectjve fines* *° mcD wllo als re, -’°” n * se J automobile experts In’ their All communications must be accompanied by the inuulrer’a name and address (not for publication), and sent to THE SUN “Service Station^!otordom, THE SUN. Auckland. Answers will appear weekly in this column.

“Essex.”—l have an Essex “four” that has lately developed the bad habit of slipping out of top gear. The gears show very Tittle wear, being almost as good as the day they left the factory. * . . , Possibly new thrust washers are needed to see that the top gear goes right home into mesh. If that is not sufficient then a. stronger spring should be fitted to the selector plunger.’ . H.C.P. (Whangarei). —I have a New Beauty Pord fitted with 31 x 4.40 balloon tyres all around. They are now - at 301 b pressure and when used at that shake the car a lot. • . * Try a pressure of 251 b all round. “Generator.” —l am having trouble with the registering of the ampmeter of my Pord car. When travelling at a speed of say 25 m.p.h. the hand often appears to be jammed and remains stationery. If I speed tile engine up it charges up to 20' amperes for a while and then drops back to 0. If the battery is o.k. (and you do not mention it) then the trouble is a faulty ampmeter. Have it tested at a reputable electrical shop. D.E.R. —Since I had a, broken universal joint replaced in my 1927 model Chevrolet, there has been a rattle especially when I apply the brakes going down hill. When motoring along slowly between 8 and 10 miles an hour on top, she rattles, and I have' to move into second very quickly. The

other day I had a friend looking at it. We jacked the wheel up, started the engine, put her into gear, ran slowly, and underneath I could hear the rattle and jumping in the differential, moving up to the universal joint. It is there, also. • * * Tour trouble seems to me a contribution of several, things rather than one. The rattle w-hich follows the application of the brakes going down hill is probably wheel bounce, which is especially noticeable in 1927 Chevrolets if the tyres are hard. The wheels lock under the brake grip and shudder over the bumps in the road, which amplifies every loose nut and bolt, as as any play in the brake-rods, into one loud rattle. Try lower tyre pressures. It makes for more comfortable riding. The rattle when in top gear and travelling slowly is probably caused by an engine buck. You cannot expect perfect flexibility from a low-priced four-cyclinder car, and the behaviour of yours suggests that the carburettor should be cleaned and readjusted. Probably the mixture is too lean, and some of the cyclinders starve when the motor is running on the idling jet. If the universal joint has as much play as you suggest when the car is stationary, it should be renewed. R.E.A. —A strange trouble has developed in my car—a light British four. It seems to have lost compression on one cyclinder, and I cannot get the usual power out of it. It runs quite well when cold; but when it gets hot the power drops off, and it is bard to keep in top gear on any road that is not flat. The trouble has developed in the last few weeks, after the engine was decarbonised and valves ground. The magneto spark is good, timing is correct, and carburettor * clean and adjusted correctly. I have tried a different grade of oil, and that made a little improvement. The engine starts easily even now.

I would suggest testing the clearance between valve stem and tappet on both valves (but more so the exhaust valve) of the cyclinder giving trouble. If the clearance is correct (as advised by agents), then I would look at the valve stems. It is common for these to get gummy, through too much oil. If this is not the cause, then the valve stem may be bent.