Spark Plug Indexing
Joined: Sep 2006
Posts: 7,415
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From: Earth, Milky Way Galaxy
Spark Plug Indexing
Saw this on Horsepower tv. Yeah yeah its the same show that says that E3 plugs and Fitch fuel catalyst work
but this actually makes sense. You face the plug the right way so the spark is able to ignite the fuel/air at a more efficient point. You do this by sticking small washers like this:

on the plug so that the electrode doesn't block ignition. They are thin enough to where they wont space the plug out too far from inside the cylinder. Seems simple enough to do too. Anyone think it might be beneficial? Anyone ever do this before?
but this actually makes sense. You face the plug the right way so the spark is able to ignite the fuel/air at a more efficient point. You do this by sticking small washers like this:
on the plug so that the electrode doesn't block ignition. They are thin enough to where they wont space the plug out too far from inside the cylinder. Seems simple enough to do too. Anyone think it might be beneficial? Anyone ever do this before?
Sounds like BS to me. You have a small area FULL of an air/fuel mixture. No matter where the spark is, that mixture is gonna blow. Its not like all the A/F mix is on one side of the cylinder and if the spark is pointed away its not going to light as well.
Joined: Sep 2006
Posts: 7,415
Likes: 4
From: Earth, Milky Way Galaxy
Yeah it will all ignite but indexing the plugs places the ground strap out of the way so the direction of the flame. A little searching and I found this:
Spark Plug Indexing - Holdenpaedia
FORDMUSCLE.com web-magazine - How To Index Spark Plugs
http://www.bullittarchive.com/5005.htm
Apparently people have been doing this for quite some time. I might try this on my next plug change.
Spark Plug Indexing - Holdenpaedia
FORDMUSCLE.com web-magazine - How To Index Spark Plugs
http://www.bullittarchive.com/5005.htm
Apparently people have been doing this for quite some time. I might try this on my next plug change.
Joined: Sep 2006
Posts: 7,415
Likes: 4
From: Earth, Milky Way Galaxy
Just trail and error. You are not supposed to stack washers so if you put the thinnest one and it still isn't indexed right then you can just torque them down a few times to crush them.
Joined: Sep 2006
Posts: 7,415
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From: Earth, Milky Way Galaxy
Nah. On the gay Ford I own now cuz it needs all the help it can get to run properly and probably on the better Toyota I will own later.
me too, but that episode made sense of it. You have to put a mark on the plug and unstall it. How many dgrees off is what determines which spacer you use. If you're just shy of the mark, back it off a retorque.
Its cheap, but will def take a little time.
it may only net you 1-2, but think of it this way:
1-2 here, 1-2 there...those small gains soon add up.
but you mustn't forget the "holy trinity" of horsepower:
"If it's good and cheap, it won't be fast.
If it's fast and cheap, it won't be good.
If it's good and fast, it won't be cheap."
1-2 here, 1-2 there...those small gains soon add up.
but you mustn't forget the "holy trinity" of horsepower:
"If it's good and cheap, it won't be fast.
If it's fast and cheap, it won't be good.
If it's good and fast, it won't be cheap."
4.6L, 5.4s, etc...
I may be wrong here but...
the machining on the engine should start at the same point on every hole, the threads should start at the same spot on every spark plug, if you were to torque them down to the same foot pounds wouldnt it be close enough?
so i am curious how you mark this on say a DOHC engine where you can barely see the plug after its installed.
4.6L, 5.4s, etc...
I may be wrong here but...
the machining on the engine should start at the same point on every hole, the threads should start at the same spot on every spark plug, if you were to torque them down to the same foot pounds wouldnt it be close enough?
4.6L, 5.4s, etc...
I may be wrong here but...
the machining on the engine should start at the same point on every hole, the threads should start at the same spot on every spark plug, if you were to torque them down to the same foot pounds wouldnt it be close enough?
its possible. I've never done it. the goal is to have the electrode to the opposite side of the valve. If the electrode is between the valves and the spark, the air/fuel has to move around the electrode to get to the spark.
That probably leaves a good 30 degrees or so that would be in that range.
What i do know in general terms- if you install the plug and its 60 degrees shy, you remove the washer and install the next bigger one. That gets you in range of just shy so that a loosen/retighten will get you dead on.
Repeat on next cylinder.
Joined: Sep 2006
Posts: 7,415
Likes: 4
From: Earth, Milky Way Galaxy
Why not just mark the socket/ extension? easy enough.





