FE sparkplugs

[Tim7139]

There have been some rather interesting discussions out there on sparkplug alternatives including some elsewhere on this site.

Does anybody out there, in particular any of our builders, have any information regarding any modern alternatives to classic plugs? I am really looking at FE based, street driven powerplants in that 450-500 HP range that would utilize an Autolite 3926, but might switch out to a Bosche +4 platinum.

Might it be a better alternative? Any testing? Any real world experience?

[philminotti]

Tim-

Personally, I've never been a big believer in plug differences...heat range and all that. Maybe for serious high compression race motors, but for our typical mills, not so much. Just my opinion, of course.

I use NGK BKR6E plugs gapped at .038". Works for me. It just seems like there are so many other things that make these motors run well or poorly, that plug choice should be WAY down at the bottom of the list.

[blykins]

Heat range actually can make a big difference for street driven cars on pump gas.

For modern heads with 14mm plugs, I usually use an Autolite AR3924. For the 18mm variety, the Autolite 45's give me good results.

[Tim7139]

Originally Posted by blykins

Heat range actually can make a big difference for street driven cars on pump gas.

For modern heads with 14mm plugs, I usually use an Autolite AR3924. For the 18mm variety, the Autolite 45's give me good results.

Thanks very much. A follow up if I may, since I've considered that plug . In a 500HP 406 with Edlebrock Performer heads 10.5 compression, where would you gap them?

[blykins]

.040" seems to work for most applications with a good ignition box.

[rodneym]

OP, please allow me to side track with a personal question...

Brent,
I've read that if you run too cold a plug, that it can overheat, and cause detonation/run on.
Does this make sense?

[Tim7139]

Originally Posted by rodneym

OP, please allow me to side track with a personal question...

Brent,
I've read that if you run too cold a plug, that it can overheat, and cause detonation/run on.
Does this make sense?

No problem at all. If I may piggyback on that...if you're going to switch up here on your plug, can I assume you maybe want to shade them a little hotter rather than colder and then check them as well as keeping an eye on temps. run-on, etc?

[blykins]

Rod,

I could see where a cold plug wouldn't allow for a complete combustion and would carbon things up....which could lead to run-on, pre-ignition, etc.