Hotter sparkplugs

Firewall Forward Aerovee
1

After a long battle with a broken alternator and secondary ignition(trigger magnet) I’m trying to gain confidence in the Aerovee again. I lost that a bit when in one flight the alternator and the secondary ignition both stopped working and rough running on only the primary ignition.

I’ve figured out that the rough running must be mixture too rich. Couldn’t lean far enough to fix it. And if plugs are fouled, its not easy to get them working again without the secondary ignition. Adjusted the needle and now on the ground it’s running good on only the primary. Have to go up to test it in flight. But still the front cylinders run richer than the rear and the plugs foul more easily. To prevent this the suggestion is to put hotter plugs in the front cylinders. Autolite isn’t easy to get here in Europe, but NGK is no problem. The NGK equivalent is the DR8ES. So, I ordered the DR7ES which is hotter. Is this a good idea to try out?

2 Likes
2

AlexZ,

Good job on figuring out you needed to adjust the needle. I had to do that a few times but never need to mess with it anymore. At least not until I start modifying things again.

Your idea is interesting. I have no idea if it will work, but you could just put in two hotter plugs on the primary and leave the secondary as is.

I lean my engine aggressively, because it’s happy there. Typically I’ll run the backs at 1350°f - 1390°F and that gets the fronts lean enough to be happy.

3

AlexZ, Have you considered iridium plugs? They may not be available where you are.

Iridium Spark Plugs - Firewall Forward / Aerovee - SonexPilots.org