Gordon Misch
MEMBER
Toledo, Wa (KTDO)
What would be the expected lifespan of massive electrode spark plugs in an O-320?
Bob, could you please elaborate on that? Thanks - -the entire personality of the Decathlon changed
Thanks EricI've been told that 500 hours is about what you expect out of a set of plugs.
Although years ago I had a set of Champions on my old C170 that musta had about a gazillion hours on them--
the center electrodes were worn down until they were a skinny oval shape, and they still seemed to work just fine.
(Bendix mags BTW)
My IA finally made me change them at annual time.
According to Aircraft Magneto Service, most bad mag checks are actually spark plug related.
Here's a link to a good troubleshooting guide. http://www.aircraftmagnetoservice.net/magneto-troubleshooting-guide
Plugs are easy to test with a simple multimeter--
they should read a maximum of 5000 ohms through them.
New plugs spec out at 800-1200 ohms.
In my experience, a Bendix mag will spark an iffy plug long after a Slick gives it up.
Bigger coil = hotter spark.
Thanks Windy. Yep, I carry an extra plug also. And my new plugs will be Tempest. An internet search led me to believe that there is no performance difference between Tempest and Champion, and Tempest are less costly. FWIW, Lycoming Service Instruction 1042AF says either engine oil or copper-based anti-seize on the plug threads. So maybe no need to carry anti-seize??I carry 2 new spark plugs, a crescent wrench, a spark plug socket, a multi-meter & some anti-seize in a baggie in my Cub tool bag,virtually guaranteeing that I’ll never have that spark plug problem again. Oh, and the new spark plugs are Tempest now.
Did the 180 when replacing cylinders and the cub at last years annual both with Tempests and would have put them in the cub sooner but couldn’t get them at the time, I won’t go back to massive’s as both engines run smoother and there is essentially no plug maintenance!Ha! For your 180? Sounds about right for 12 of 'em!! (plugs, not kidneys:roll
In a J-3 they will last forever. The joke here is that I got Greg Madariaga's rejects out of a Cherokee in 1978, put them in my Cub, and am still using them....