What's Happened to Secondary Wiring Life? 720918

The deterioration of secondary ignition wiring life on today's internal combustion gasoline engine has created many maintenance problems in the field. The mandatory use of TVRS (resistance wire) has amplified these problems and made them more difficult to solve. The solution does not lie solely with wire design-engine application, engine design, and component selection and location are also important factors.
THE LIFE SPAN of the secondary wiring used on gasoline automotive engines dropped dramatically with the introduction of resistance-type wire which is commonly referred to as TVRS wire.
The TVRS wire was introduced to suppress ignition interference in accordance with SAE specifications, and to meet the requirement of Public Law 200 passed in October 1951. The TVRS wire was also intended to reduce spark plug electrode erosion. While both of these missions were accomplished, in most cases the wire had a very short life. There were various reasons for this short life, and as some of the problems were corrected others developed. Today, the short life of the wire is a constant concern of the maintenance people both because of cost and reliability factors.
This paper will detail field problems encountered in today's special application internal combustion engines in regard to secondary wiring life, highlighting the effect that engine design, component selection, location, and engine application have on wiring life.


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