Periodic Maintenance Preserves the Life Of a Car

Poverty Bay Herald, Volume LXIV, Issue 19337, 29 May 1937, Page 9

Periodic Maintenance Preserves the Life Of a Car

QNE of the most, important of the

periodic maintenance jobs which must be done to preserve a car is the top overhaul, which includes decarbonising, valve grinding, and tappet adjustment. The work should also include general adjustment of the ignition system and tho carburettor.

Host service managers of car distributing firms are of opinion that a car should receive its first top overhaul not later than the first 8000 miles, and thereafter the work should be done at least, every .10,000. miles. There are exceptions, of course. One car has been designed for its valves to operate without, attention for 20,000 miles, but even in this case it is considered wise for carbon to be removed at least twice within this period.

If a car is allowed to operate for long periods with no attention to the combustion chambers, the valves will invariably so pound themselves out of shape that most of them will have to be replaced. They will fail to make a properly sealed joint against (heir seats, and will, burn away, and tho piston (ops and cylinder heads ■will accumulate carbon, so that engine performance will decline to a fraction of what it should be.

Cheaper in the Long Run. it, is important, therefore, to heed the advice of the company from which a car is purchased. It is far cheaper (p spend a little once every nine months or so, than to pay for a complete new set of valves and seats, and far more pleasure, is to be derived from sitting behind an engine that is in good condition than one that is thoroughly "sick." Years ago, it was common for motorists to carry out Iheir own top overhauls, but with the, great strides that have been made in workshop practice, and the new machines and tools which have been designed for making car repairs more efficiently and cheaply, it is hardly worth while to-day for the private owner to tackle the work, unless ho is tremendously interested in mechanics and has a sound knowledge of the subject.

it is far better (o entrust the car to a properly equipped workshop. This establishment will have cutters and grinders which ensure good valve seats, jigs for checking valve stems for warp, and mechanics thoroughly accustomed to the car and its idiosyncrasies. Grinding in valves with carborundum paste without first rocutting the seats and valve faces by machine is a long and monotonous job, and it is doubtful if even reasonably good results can be achieved. An inexperienced owner would certainly find some difficulty in lifting the cylinder head, and in removing and reinserting valve cotters and springs. A Filial Check Over.

It is far better then to lay up the car for u day at a garage and have the work done expeditiously and well. The motorist must remember, however, that it is essential to return the car to a garage after it lias covered about '2OO miles, for linal tightening and checking. There is yood reason for this.

Most good mechanics insist on using a new cylinder head gasket when once the head has been removed, and in llie first few miles this will be compressed so that the cylinder head studs can be taken n)) a few threads again. If this is not done, there will be a considerable risk of the gasket, "blowing" and allowing water from .the cooling passages to leak into UlO cylinders.

Furthermore, the valve lappets will first be adjusted very loosely to give the valves plenty of scope for settling intot their seats. During this 200 miles the valves will drop perceptibly closer to the tappet heads. They will still be 100 loose, however, and the tappets must bo adjusted to the recommended clearance. This final check and adjustment is a normal part of the top overhaul, which is not completed until it lias been done. Returning the car in this maimer will also enable the man who did the work to check over the water connections he made when re-assembling the engine, and to see that no minor "weeps" have developed, and to tune the engine generally.