You’ve got to try very hard not to love NGK D(X)EA plugs.
Agreed Stan. Mine runs DP8EA9. I get them at the local motorcycle shop.
I "love" it when the guy asks me what it fits and I tell him. I understand he's just trying to be helpful and make sure I'm getting the correct plug. Then he looks all puzzled like, because it doesn't compute. Just give me 4 Sonny.......
Next time I go in there's a pretty young thing(PYT) behind the counter. I say I need 4 DPxxxx and she thanks me for not making her look it up. Go figure.
This may help for those who want to know what the numbers mean:
DannyP posted:This may help for those who want to know what the numbers mean:
Without wanting to hijack the thread (but I think the original question was answered) what is the benefit to a hotter plug and some of the other features etc? I understand why the reach (E) and the shell size (B) is important but what does the rest of the choices do for the plug?
Robert M posted:DannyP posted:This may help for those who want to know what the numbers mean:
Without wanting to hijack the thread (but I think the original question was answered) what is the benefit to a hotter plug and some of the other features etc? I understand why the reach (E) and the shell size (B) is important but what does the rest of the choices do for the plug?
Such a great question.
When I was a kid, I thought a "hotter" plug meant that the spark produced would be greater. It's not.
At its simplest, a "hotter" plug glows longer after the spark event is over. Super-rich air/fuel mixtures take a hotter plug to light the fire in the cylinder. But a hotter plug is a detonation kernel in the cylinder, so in general you want to run the coldest plug possible before you get a misfire.
Air-cooled engines have a lot of problems with detonation and pre-ignition by the nature of their ineffective cooling. To some extent we paper this over by running much richer than more modern designs need to at wide-open-throttle (WOT). Needlessly adding a little glow-plug in an already hot cylinder only serves to invite an explosion in the cylinder, rather than a nice progressive burn.
Higher compression engines typically run colder plugs. With NGK plugs, the higher the number, the colder the plug. Plugs up to the "8" heat range are pretty easily accessed, but to get a "9" or "10" are racing plugs and generally means big money and making some other compromise.
if you have a standard 1776- 2110, with a milder cam (W120 or milder) and run less than 9.5:1 CR, a "7" heat range is really nice. With 10.6:1 CR, I run "8s", but I should probably go to "9s".
Now I have to check my plugs. Quit teaching me stuff!!! (Just kidding)
If you pull one, Bob, it should look tan and dry. If it's sooty, you need a slightly leaner mixture or a slightly hotter plug. If it's white and powdery, it's the opposite.
The numbering from hot to cold runs in opposite directions on Bosch and NGK.
Yeah, Michael, they do.
That's because Bosch and NGK are messing with our heads.
Gordon Nichols posted:Yeah, Michael, they do.
That's because Bosch and NGK are messing with our heads.
NGK (and Denso) run opposite Bosch. Champion can't decide what they want to do.
For your dancing and dining enjoyment:
Well, since you bring up Denso, and since the thread drift here isn't nearly up to our usual standards, and since I feel like stirring the pot a little...
My builder, for some reason, spec'd and installed Denso plugs for my new engine, about four years and 20,000 miles ago. No problems since, and the plugs have always looked OK - not too sooty, not too powdery.
I'd always used NGK, so wondered about this choice, but figured he knew more about keeping his engines happy than I did. These ARE 12mm plugs, and apparently the equivalent of an 8 heat range in an NGK, even though the motor's a pretty mild, 8.5CR build.
The Denso number is X24EPR-U9 .
I replaced them after about 10,000 miles with a new set of the same, not because they needed it, but well, just because. After another 10,000, all's still good.