2,000 MILES PLUG TEST.

THE sparking plug manufacturer probably deserves one’s sympathy more than any other supplier of motor car accessories. Motoring nowadays has become such a utilitarian means of transport that even in a sports car the average motorist demands a plug which will both fire regularly in a traffic hold-up and allow the full road performance of the car to be used. Being enthusiasts ourselves, we do not particularly mind changing plugs, but when we find a plug which will deal with a wide range of conditions, we consider it marks a definite advance. The type 677 plugs embody the usual K.L.G. features of mica insulation and

spring clip. The centre electrode is not very heavy, but is protected by heavy mica insulation almost to the point, the ends of the centre wrapping being protected from heat by a metal cap. At the same time, the body has a wide opening, which allows heat to get to the insulation and keeps it free from oil. The plugs were tested in a 4i-litre supercharged Bentley, which provides a wide range of running conditions. A considerable amount of oil accumulates in the supercharger overnight, so that when the car is started in the morning the plugs have to deal with a good deal of it. The

same applies in town driving and traffic stops. When driven all out, the engine runs hot and the compression rises to about 6,3 at 4,000 revs.

A 2,000 mile test has been carried out, and in the course of it, we only had one case of plug trouble, the plugs in the front cylinder oiling up through running the engine too slowly when warming up. Apart from that, they have given no trouble either in running about London or in full throttle work on the road. Type 677 cost 12/6 each, but as they overcome the need of two sets of plugs, for town and open road use, they justify the initial outlay.