Introduction

When driving a petrol-engined car, pinking is a symptom of maladjusted ignition timing, or using an incorrect grade of fuel.

The ignition timing is responsible for causing a spark at the correct moment so that the petrol-air mixture ignites as the piston is on its power stroke.

For maximum power, the explosion should occur when the piston is as close to the top as possible without actually being at the top. This means that the mixture is fully compressed, and the explosion will exert maximum force on the piston.

Pinking occurs when the explosion happens as the piston is exactly at the top of the stroke; the crank, connecting rod and piston are all in line. In this position, the explosion attempts to push the piston and conrod through the crankshaft via the big end - not a good situation.

Identification

When an engine pinks, there will be a sudden loss of power and an accompanying noise - a high-pitched pinging rattle rather like a diesel engine on start up.

Allowing pinking to continue can cause serious damage to the engine very quickly, although the problem is alleviated temporarily by adjusting your driving style.

Remedy

The immediate solution to alleviate the problem is to drive more conservatively, completely avoiding hard throttle at low revs. This should get you to a service station or to your home if you are going to attempt your own repairs.

Assuming you are using the correct grade of fuel, the long-term solution is to retard the ignition timing slightly so that the spark occurs further around the cycle and the explosion occurs after the piston has passed top dead center. Retarding the timing too far will not cause problems up to a point, but power and efficiency will be lost to some degree.

Pink"ing, n.

1.

The act of piercing or stabbing.

2.

The act or method of decorating fabrics or garments with a pinking iron; also, the style of decoration; scallops made with a pinking iron.

Pinking iron. (a) An instrument for scalloping the edges of ribbons, flounces, etc. (b) A sword. [Colloq.]

 

© Webster 1913.

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