MORE CYLINDERS

Wanganui Chronicle, Volume 73, Issue 115, 17 May 1930, Page 13

MORE CYLINDERS

INCREASING SIZE OF THE MOTORCAR ENGINE. Although cars powered with engines of eight cylinders have been upon the market for fifteen years, and within this period many manufacturers of higher-priced vehicles have produced eight-cylinder models and some have even adopted this type exclusively, it is only within the last season or two tha* the eight-cylinder engine has begun to be offered in cars of medium price. The present trend toward eight-cylin-der cars, offered at medium and even low prices, is very marked, and very closely resembles, the movement from the four to the six, which is a matter of rather recent history.

Motorists arc consistently seeking smoothness jf operation on their cars, and the multiplication of cylinders is the obvious and effective answer to this demand upon the manufacturers’ part. Improved production methods have enabled the somewhat more complicated eight-cylinder engine to be marketed at a cost but slightly higher than that of an equivalent six, as built a very few years ago. Exactly the same thing happened as between the six and the four not so very long ago. Until rather recently most eightcylinder engines were of the V-typc, but now the tendency is towards the straight eight or eight-in-line style. Both these types have their adherents, and there is likely to be a vigorous competition between them. While multiplacation of cylinders and the consequent reduction in individual cylinder displacement results in smoother operation, on the other hand the resultant complication and reduction in fuel economy due to increased heat and frictional losses, in some degree offsets the advantages gained. However, careful design insures a degree of fuel efficiency for the eight, which appears to be satisfactory to most users.

Veteran motorists who remember the “one lunger,” its conquest by the twocylinder, the triumph of the four over the two, and the displacement of the four by the six, will naturally look upon the encroachment of the eight upon the six as but another chapter in the orderly development of luxurious motoring—and will wonder what next. Already the first twelve-cylinder models have established themselves. The “Missing” Cylinder. One peculiar result of the tendency to multiply cylinders is that the time may eventually come when only a mechanic will be able to decide whether or not a cylinder in an engine is ‘(missing.’ ’ It seems hardly possible that the driver of a “four” with a cylinder which is not firing can be ignorant of the fact, but there are people so insensitive to mechanical derangements that they do not sense it. With a six there is a little more excuse for nofr noticing a “dead” cylinder, and an inexperienced operator without mechanical inclination, may fail to realise what is causing the obvious' loss of power. In the case of an eight, running at other than very low speed, the continual misfiring of a cylinder causes no very pronounced disturbance and may not be noticed by other than a susceptible motorist, except as loss of power—possibly attributed to some other cause.

Every driver should be on the watch for a possible “missing” cylinder,indicated by vibration, roughness of operation, or lack of power, and should not tolerate the failure of any cylinder to fire regularly longer than is required to reach a place where the defect can be overcome.

Of course, when a cylinder is “missing” all the fuel which it takes in is lost, but this is the least of the evils of the “dead” cylinder.

This petrol is far worse than wasted, for the portion of it which is not expelled through the exhaust condenses as liquid in the cylinder, trickles down the cylinder walls, and removes the film of lubricating oil upon them, with, the result that the piston rings wear the cylinder bore excessively, and may in time stick and score out seriously. A “missing” cylinder is less noticeable as engine speed is increased, and the tendency is for the driver to drive fast in order to make tho engine run as smoothly as possible, bringing about the very conditions which make damage to the bore of the “dead” cylinder most likely. Tho fuel which flows down the walls of tho idle cylinder may, in time, dilute the crankcase oil so greatly as to cause damage to bearings or to other cylinder bores.

Jerky and laboured running at low speeds, resulting from a mis-flring cylinder, imposes abnormal duty upon bearings which may hasten their loss of correct adjustment.