14mm Automotive Plugs in Lycomings

[Wingit]

My experience after reading Paul Dye's article in Kitplanes, "Automotive Plugs in Lycomings", June 3, 2023. I also posted this as a comment online under the Kitplane article.

I’ve used PMAGS now for 13 years, always using the recommendation from the manual. However, after reading Paul’s article, the idea to use a higher torque for the adapter made sense.

So I tried it the other day with less than perfect results: I intentionally broke an old BR8ES plug at the base of the ceramic to allow plenty of room for my adapter size socket to clear this modified plug. Inserted the modified plug into the brass adapter and then torqued the adapter to 35 ft lbs. Backed out the modified plug, then inserted the real spark plug and torqued that to 16 ft lbs. This worked fine on 2 plugs.

But, on the third cylinder the adapter broke off prior to reaching 35 ft lbs. This left most of the adapter firmly in the spark plug hole. Since I was hoping to fly the next morning, this was a real disappointment. Fortunately, a local mechanic had the appropriate easy-out and was able to remove the broken adapter.

My torque wrench had not been recently calibrated, so maybe I was using too much torque. Also, my brass adapters were all 13 years old. As luck would have it, I intended to replace all adapters at next condition inspection. Regardless, my take is that while aviation plug torque may be fine for steel adapters, I think it’s too high for brass, particularly old brass.

I hope my experience may prevent someone else from having a similar problem. For me, I’m going back to the Emagair recommended method that has worked so well for 13 years.

 

[Wingit]

I‘ve got the same problem what was the correct easy out that your mechanic used to remove the plug insert

Thanks,
Dave

 

[revenson]

I‘ve got the same problem what was the correct easy out that your mechanic used to remove the plug insert

Thanks,
Dave

Sorry Dave, don't know.

 

[amckeen]

The BR8ES are a massive electrode. In Canada $4.50 to $5.00 Cdn pesos each and yes, that is cheap. The NGK 6747 are a fine wire at $14 to $15 cdn pesos each and still relatively cheap. Light Speed recommends fine wire and these don't appear to be one of them.
I'm running BKR8E1X that I paid around $20 each for the top 4. And will run on condition and aim for 500 hrs. Never really ever much cleaning to do on fine wires so not a big deal. Again a lot of vehicles today run 100,000 plus miles on the original plugs with zero problems. Yes autos are unleaded and we are fully leaded.

Here we can't buy much for $2.00

Tim

 

[amckeen]

NGK 2668 BKR8eix currently can be purchased from sparkplugs.com for $8.45.
It has solid terminal.

The advantage of this plug is that it has smaller 5/8 inch HEX size rather than the BR8eix 13/16 hex that makes separate torque of insert adapter easier with the tools I have.

The projected center electrode may also have advantage over non-projected center electrode.

Forum search for BKR8EIX suggests that they are used by others successfully with p-mag and lightspeed ignitions.