Spark plug gap?
Banned
Joined: May 2018
Posts: 4,576
Likes: 978
From: Viet Vet, crossroads
You think the "big Sucker " would have anything to do with plug gap?
LOL
The higher the CR the smaller the gap.
If you are stock with the super lean 14 AFR numbers, most any plug will jump 040 and a lot more.
LOL
The higher the CR the smaller the gap.
If you are stock with the super lean 14 AFR numbers, most any plug will jump 040 and a lot more.
Stellar HDF Member
Joined: May 2007
Posts: 3,256
Likes: 522
From: USA
I don't understand this thread.
My understanding is that copper (actually gold) as a metal
flows electricity better than any other metal.
Outside/ ambient temperature of whatever metal the spark plug's
is made of I don't see any science of that temp change effecting
electrical flow. Although some say colder environment the better
for electrical circuits.
Easy starting, smoother idle, yes I too would call a performance increase.
New plugs always make an engine "feel" better.
So with many of our co-member stating NGK Iridium plugs are the ones to
install over copper OEM (Champion) I don't understand.
The side electrode and the center electrode size and shape seem to me
as the only variable. Just as indexing, the more spark exposed to the fuel charge
the better.
So to aid my understanding, is the electrode shape/ design what our co-members
are "raving" about?
I just can't believe iridium (platinum etc) over copper metal is the rave.
My understanding is that copper (actually gold) as a metal
flows electricity better than any other metal.
Outside/ ambient temperature of whatever metal the spark plug's
is made of I don't see any science of that temp change effecting
electrical flow. Although some say colder environment the better
for electrical circuits.
Easy starting, smoother idle, yes I too would call a performance increase.
New plugs always make an engine "feel" better.
So with many of our co-member stating NGK Iridium plugs are the ones to
install over copper OEM (Champion) I don't understand.
The side electrode and the center electrode size and shape seem to me
as the only variable. Just as indexing, the more spark exposed to the fuel charge
the better.
So to aid my understanding, is the electrode shape/ design what our co-members
are "raving" about?
I just can't believe iridium (platinum etc) over copper metal is the rave.
Ultimate HDF Member
Joined: Jul 2014
Posts: 5,649
Likes: 430
From: MASS_hole
For my014 twnk, I switched to ngk irridiums almost instantly. 30k and am hetting ready for anew set.
Gap ‘emat 0.40, sharpie open end and will attept indexing.
I understand the placeent is to point the open end towards the intake. But where I get a little confused if proper torque. Or just go by feel?
Gap ‘emat 0.40, sharpie open end and will attept indexing.
I understand the placeent is to point the open end towards the intake. But where I get a little confused if proper torque. Or just go by feel?
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,092
Likes: 7,614
From: Poolville
In my 1998 FSM, it states to coat the threads of the plugs with engine oil and torque to 18-22ft lbs. I don't think there is any difference in trying to clock the ground strap... Your compressed air and fuel is swirling in the cylinder head like a f7 tornado... Just put them in your not going to change performance...
Seasoned HDF Member
Joined: Sep 2012
Posts: 6,570
Likes: 590
From: almost there
A 5 would be a fairly hot plug with NGK. Smaller #s are hotter with NGK. 7 or 8 would be normal heat range.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Thread
Thread Starter
Forum
Replies
Last Post
hulsera
Ignition/Tuner/ECM/Fuel Injection
4
Nov 23, 2008 08:55 AM