“SUN” SERVICE STATION

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

“SUN” SERVICE STATION

►'gVHL “MoLordom" section of Tfie Sun includes m Its service to readers a A Queries and An.-vrers Department, the object of which is to give accurate Information regarding mechanical and touring subjects. Whatever the particular puzzle may be tn either diagnosing Irritating croubles or motoring information of any kind. “Headlight* will endeavour to help, or refer the point to meD who are recognised automobile experts in their Pe All communications must oe accompanied oy the inquirers name and address (not for publication), and sent to TUB SUN “&ert>tce Station, Motordom” TUB SUN Auckland. Answers will appear weekly in this column

Devon port.—l have a Lucas magneto on my H.S.A. motor-bike. It is misand the spark on the platinum points is very weak and is not going through the sparking plug. The platinum points are open freely, 1-04 inch. The magneto is not wet and I have cleaned it without any result. 1 I would be grateful if you would tell me how to adjust it.. The magneto, if functioning correctly should not spark at the platinum points. It it is sparking, the condenser will require renewing or reinsulating. The cause of the spark at the sparking plug being weak can be one of many troubles. For instance, if the armature winding has broken down and is faulty, it will necessitate rewinding the armature. This could also be caused due to a faulty slipring, faulty condenser, or weak magnets. We would suggest that if you are not conversanf enough with this machine to discriminate which of the troubles you may be experiencing, you would then be best advised to take it into the agents, and ask them to have it tested. If the condenser is faulty you will note when the machine is running that the platinum points spark considerably. If the magnets are weak, it will turn over very freely. If the magnets are 0.1 C.. and the condenser is all right, probably the armature winding has broken down, and is giving a weak spark. As this is a highly skilled job to repair, it will necessitate sending it in to people who cater for this class of work. P.K.—Can you tell me the valve timing for a 1927 model Rover 9 li.p car? I would like to know when the exhaust valve closes and the inlet opens with relation to the top dead centre. The inlet valve opens two degrees after top dead centre, and the exhaust valve closes 12 degrees after top dead centre. Alis.—l am a reader of jour hiotor section, and would like to ask a few o.uestions. (1) I have a Chevrolet truck, 1927 model. Lately it has not been pulling very well up hill, so I had new piston and oil rings installed, which made no difference. What may

be the cause of this Would it be the clutch bands, and could they be adjusted. (2) Also since the piston-ring* have been Installed, the engine is using a lot of oil, about two quarts every 90 miles. Could you tell me a remedy for this? (3) Also, since the rings have been put in there is a knock when I am doing 25 rn.p.h. (4) The speedometer is fitted to the shaft at the universal joint. When I first had the truck there were 30 x 5 tyres on the back wheels; now I have 32 x 6. Would this make a difference in the registering of the mileage and speed? I would glad of advice. As your truck is three years old. it is assumed that a considerable mileage has been covered. If such is the case, merely installing new piston rings would not necessarily overcome lack of power, for it is quite possible that the cylinder bores have worn to some extent, and they also might be worn oval. In this case oil pumping would most likely result unless the cylinder bores were honed before new rings were installed. Lack of power might also be caused by worn clutch discs and, if so it is necessary that these be replaced. If the rear tyres have been increased from 30 x 5 to 32 x 6 it would certainly affect the speedometer reading and the speedometer would therefore read slow. It is difficult to diagnose the cause of the engine knock. Communicate with the authorised Chevrolet dealers in your district and get them to look over it. C.B.—After leaving it in a garage for a week my car will not start with self-starter. l»ut does quite easily by nanil-cranking. 1 f my battery is weak, which I think it is, is it detrimental to either battery or car to keep on using weak battery and keep on hand cranking! ~ If the , battery _was all right before : oek in garage, then it appears to have been left there, with the lights or the switch left on, or more probably, with a short in the wiring. Hand-cranking does not harm either the battery or the car, but using a v eak battery for lights, horn and so on, ruins iL Letter have it recharged