[DeTomaso] Plugs (long)

Thomas Tornblom Thomas.Tornblom at hax.se
Thu May 21 16:17:22 EDT 2009


JDeRyke at aol.com skrev:

> 
> As an aside, special electrode plugs in a street car are another way of 
> separating you from your money with little real benefit. Multi-electrode plugs 
> were used in ancient DC-3 aircraft in the 1930s as an aid to reliability 
> where changing a shorted plug was inconvenient (like, at 10,000 ft in a 
> snowstorm). This seldom happens to passenger cars except in Colorado. Good luck, 
> all- J Deryke
> 

VW/Audi use multi-electrode plugs since the 80:s for for service 
interval reasons. A three electrode plug, which is what I've seen in the 
VW/Audis I've had, have a much longer life (3x?) than a single side 
electrode.

A multi-electrode plug only sparks from one of the electrodes at a time, 
and when the gap on that electrode has opened up due to wear, the next 
closest electrode takes over.

The recommended change interval is around 40kmi, and one can clearly see 
that all electrodes has been firing when replacing a worn plug as the 
center electrode is triangular instead of round, as it was when installed.

It is true that the plugs are more expensive than standard single 
electrode plugs, but the longer life and less maintenance required evens 
that out.

Thomas



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