Question Automotive plugs in aircraft engines?

[Neal]

Per my other thread I've had issues with coil packs failing with my lightspeed ignition. CubCrafters via Lightspeed recommend the Denso IK27 iridium plugs. In testing my plugs by measuring resistance, I had 6 that were 5.7 kohms, one was 4.9 and the other 6.3 which I discarded, pulled two more and they tested at 5.7 as well. Denso lists them as 5 kohm plugs. I emailed Denso to inquire about potential quality issues and they were beyond rude, first response was "Denso plugs are not approved for aviation." Second attempt to ask about the difference in resistance just got back their web site spec info showing 5 kohms. I gave up.

So the question in the end is, why ARE we using automative plugs in our Lycoming IO-360 engines?

 

[Cactus Charlie]

Why are you using automotive coil packs on your IO-360 engine?

Answer to both is that's the system that Lightspeed provides.

I doubt the resistance variation you are seeing is of any consequence but, if you need an answer, try asking Klaus.

 

[ve6yeq]

As far as I can tell we are using spark plugs designed for high performance automotive use (look into the car models that use the Denso IK27 plugs) as the design is way more modern and better performing than classic aviation spark plugs.

If only the same amount of effort went into light aircraft engine design as goes into high performance car engine design…