Most miles on original spark plugs ?

[Racerjk]

I'm at over 82k on the plugs in my Formula. The car still runs fine to me. I've heard nightmares about the plug changes on these cars,but some also say it's not too bad.

 

[otis24]

2000 Chevrolet Venture came into the shop a couple of days ago. It had 203k miles. The plugs, and many other things were original to the vehicle.

Changed the plugs on my Grand Caravan at the recommended 75k. Currently, it has 141k. Almost time to replace them again. May consider Iridium plugs on th next go around.

 

[DogLover]

I had over 240,000 miles on a 2001 Grand Prix when I traded it in with the original plugs still in the engine. The car ran great and the mileage had not gone dropped.
Terry

 

[cchase]

Originally Posted By: TFB1
Originally Posted By: cchase

I am absolutely, 100% sure that it is a linear relationship. The voltage required to initiate a spark across anything is a function of distance and is a constant for any material.


No way, the amount of compression also creates a variable in the amount of voltage needed to jump the gap...

From a chart in the ARRL Hand book, of course these are "free air" measurements of a sharp point not influenced by the amount of compression in the cylinder...



Resistance of any material is a linear function of length. This is like... Electrical Theory 101. Air is a material that has a specific resistance. In normal, dry air it's about 30,000 volts per cm if I remember correctly. That means in order to bridge a 1 cm gap, you need 30,000 volts at which point a spark will discharge. To spark a 2 cm gap requires 60,000 volts under the same circumstances.