PLUG-FOULING: A USEFUL HINT

Bay of Plenty Times, Volume LXVII, Issue 12820, 15 August 1939, Page 6

PLUG-FOULING: A USEFUL HINT

DIFFICULTIES OF THE RUNNINGIN PERIOD It is sometimes found that during the runmng-in of a now car there is a tendency for the sparking plugs to become fouled. A little thought will show why this should be so. When a car is being “run-in’’ it is Essentially being operated at its minimum efficiency, whereas all the accessories fitted to it are obviously capable of withstanding all the stresses placed on them under nor-: mal or even hard driving conditions. Plugs in particular have always to do two things—keep hot and keep cool! They must retain sufficient heat to burn off the oil thrown on them, and at the same time they must conduct sufficient heat away from themselves to prevent pre-igni-tion. When an engine is running slowly the plugs do not becom.e very hot; yet all the time oil is being splashed on to them. Under, normal running conditions plugs can cater for these opposing conditions, but apart from the continual slow-run-ning, of a new engine, most owners use upper-cylinder lubricant, which naturally increases the amount of the plugs must withstand.

Cleaning and careful gap-setting are 'all that is necessary to overcome any fouling difficulty, and when the car has completed its running-in period and is .working under normal conditions it will be found that any fouling tendency will automatically cure itself. ,

Whether or not fouling, has been experienced during running-in it is strongly recommended that after their first 500 miles the plugs should be carefully cleaned and reset. Thereafter it. should only be necessary to give them attention every 1,500-2,000 miles, and this regular inspection will ensure trouble-free service.