Sparkplug life

[alcladrv]

How long do massive electrode Unison sparkplugs typically last? I've got 300 hrs. on mine and they show a little erosion, but still seem to work OK.

Mike

[terry_georgia]

Here is the story for mags - not sure about electronic ignitions.

It is not unusual for the plugs in a properly timed engine to last TBO so long as they are cleaned, rotated, and have the gap set every 100 hours or so. There is a specific rotation required because the sparks from the mags alternate between a negative spark and a positive spark (one plug will be negative and the next will be positive). One will erode the center electrode and the other will erode the massive electrodes. Rotation will even the wear (much like rotating your tires). Take the even plugs and put them in the odd cylinders and if it was in the top, put it in the bottom and that usually does the trick.

[RV6_flyer]

I presently have over 1,100 hours on my Champion Spark plugs. I rotate them top to bottom next in firing order about every 200 hours. They get checked with an erosion gauge for wear. http://www.aircraftspruce.com/catalo...ct482gauge.php
I never abrasive blast them. I only use a vibrating pencil cleaner. http://www.aircraftspruce.com/catalo...theleadout.php

I had Auburn plugs for 900 hours before the Champions. I put the Champions in right before a trip to Alaska in 2001. 83 hours flying in 3-weeks on that vacation.


Note: Added 9 May 2008
I do LEAN very aggressively including on the ground for taxi. This helps reduce lead deposits.

[alcladrv]

Thanks for your help.

Mike

[terry_georgia]

Gary's post is more technically correct than mine - it is recommended by most manufacturers to rotate in firing order, but many folks take the short-hand approach and just do odd's to even top to bottom (either will give good results).