[A26B]

Originally Posted by XfireZ51

I’m using the BKR5E but gapped at .035”. Wonder why Corey feels .042 works better?

0.042 is in between 375 & 405 models which were spec'd originally @ 0.035 & 0.050. To the best of my knowledge, there was no change in spark components & was likely a change in thinking bigger gap, hotter spark = better propagation.

Resulting experience of owners having rough idle issues, and thinking gap @ 0.050 was too much & the cause of rough idle. Changing to 0.035 resulted in smoother idle for some.

Somewhere in the middle 0.042, is a good compromise & allows for some electrode erosion without issue.

I run 0.050 with Iridium plugs & works fine for me with 12:1 compression. I believe personal experience from trial & error will vary from person to person & engine to engine.