Winter and Spark Plugs

Poverty Bay Herald, Volume LXII, Issue 18763, 20 July 1935, Page 9

Winter and Spark Plugs

■CTACTING troubles in winter nr. i not as common as they were “few vears ago, since improved car buret ion and ignition systems am better fuels have made engines mon I ready .to lire, even when cold. But there, may lie much delay and wastage of the storage battery if the, spark plugs are neglected. It. is important that, the high-tcusioi leads should lie in good order to on sure thorough insulation of tho high tension current on its passage Iron the distributor to the plug terminal.-', and it is also .advisable to oierhau the ignition, seeing.that the battery ■ fullv charged and' the contact breakci points dean, well dressed, and sc! t the prescribed gap. The aim is to procure a fat and re }itist spark as soon as the ignition 1switched on and the starter motoi cranks the engine.

Deficiencies of the mixture due ti cold manifolds and lack ot volatilit.' can thus bo overcome, but it wii often bo helpful to allow tko startci to turn the online a few times while the throttle is well opened in order that a tairlv rich mixture can b< drawn into the cylinders. That advice is more applicable to older models than to those which have ‘ ‘ self-start ’ carburettors and similar equipment. If there is a manual spark control tin lever Should be put in the retard position to obviate the risk ot a “back-kick,"' which might damage the pinion gear. None ol these precautions, however, will ensure easy start ing if the spark plug's themselves are defective. The commonest faults are dirty and carbonised insulating cores, which allow some leakage of the current, and unduly wide (taps. In service, the electrodes ol tie. jdllf’s tend to burn away and so to increase the gap, but no definite gap width can be laid down.

'The car owner should be guided by the instruct kins contained in the ear manufacturef’s handbook. Ordinarily tin' gap recomentnded varies between one-fortieth and one-fiftieth of an inch, and the tendency in the case ol modern engines because of their higher compression ratios is to choose a narrow gap, as the greater compression pressure increases the electrical resistance between the points; yet il hints I be rlbservcd lliat with some ol ihe latest models a comparatively wide setting is advised. The fact to remember is that the gaps at all plug points should be uniform and should be adjusted by means of a proper feeler gauge arid that the central electrode should not be bent, since such treatment might crack the insulating core.