Hotter plugs redux

[HalcyonS]

I've been looking around old posts for stuff about hotter plugs.

Mo said
I've been using NGK XR4 plugs for 3 full seasons now...they run hotter than anything we have been proclaiming ... my mileage improved, I have no crud on my plugs, and haven't had a problem with the engine as such.

Caleb said
I've begun using Autolite 437 spark plugs which are supposed to be hotter and have been impressed with how little they seem to soot up the way the Champion RJ12C plugs did in my old engine.

Dave said
open up the gap a bit to make it hotter

Carl said
Larger gap also leads to premature wear on ignition components, for points 035 is good.

There seems to be a downside to opening up the gap. Is there a downside to hotter plugs. If not, who recommends what: Autolite 437? NGK XR4? Something else?

Simon

[roadnsky]

I've been using 437's since 2008. Gapping at .038~040"
Love 'em...

[Dave Neptune]

Whoa there

Carl and Dave said.

I can't figure out how to bring over the quotes to a reply~a lil help out there please.

Simon, the gap has nothing to do with ware! The gap is close to it's max usable because as soon as you start using points they start to ware and the "spark" is compromised and will steadily become weaker making the "jump across the gap". This is what Carl is referring to.
With the E/I there is no ware and larger gaps can be used and taken advantage of due to the "higher intensity" of the spark created.

Dave did not say the bigger gap makes the plug hotter, as the plugs ratings are at power levels where the "heat range" is applicable. The larger gap at idle does not make the plug hotter it creates a bit more heat around the tip when the engine is idling and working it's way up the RPM range. Once the engine is working hard enough the gap has no real affect on the "heat range".

Dave Neptune