This is topic spark plug indexing question? in forum Tech Talk at Northern California Ford Owners  .


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Posted by shade-tree (Member # 298) on :
 
ok, call me a ricer or whatever. But here I sit, with a couple boxes of autolite plugs, my GT-40 heads, and some questions:

when indexing plugs, do you *have* to use indexing washers? or can you re-insert the spark plug to a different location when you 'start' the plug so that it 'cinches down' in the right location every time?

I have heard index washers suck because they pull the plug "out" of the chamber ever so slightly.

By the way, do I point the 'open' side of the plug at the middle of the intake valve, or what?

Lastly, when you 'trim' the firing arm, do you bring it back to the center of the electrode, or what?

heh.
 

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Posted by FasterDamnit (Member # 442) on :
 
http://www.fordmuscle.com/archives/2000/07/indexplugs/index.shtml

Cut the ground strap so that it is even w/ the edge of the electrode, not over it at all.

JL

[ October 15, 2002, 10:51 AM: Message edited by: FasterDamnit ]
 

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Posted by HungryHippo (Member # 537) on :
 
i have always wondered about index washers too, wont they change the heat range of the plug?
 

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Posted by shade-tree (Member # 298) on :
 
sounds cool Jim, thanks. That's what I've been trying to do myself actually. I've got a few pointed at the intake valve already. Should I swing it to the exhaust you think?
 

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Posted by Yung Than (Member # 728) on :
 
What is indexing, and what is the purpose of it?
 

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Posted by shade-tree (Member # 298) on :
 
the ground strap of the spark plug (think conventional copper plugs) will hurt power somewhat if it is blocking the path to the combustion chamber. specifically, you want the 'open' face of the spark to have free access to the combustion chamber.

you guys buy underdrive pullies right? gears? exhaust? MSD coils and ignition boxes? bypass the PS pump? same idea. another HP or two, who's gonna know? stealth mod, lol.
 

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Posted by yellow67stang (Member # 903) on :
 
Why bother! Its a waste of time.
 

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Posted by FasterDamnit (Member # 442) on :
 

quote:

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Originally posted by shade-tree:
sounds cool Jim, thanks. That's what I've been trying to do myself actually. I've got a few pointed at the intake valve already. Should I swing it to the exhaust you think?

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quote:

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Originally posted by Yung Than:
What is indexing, and what is the purpose of it?

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Read.......
http://www.fordmuscle.com/archives/2000/07/indexplugs/index.shtml
 

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Posted by 93PONY (Member # 60) on :
 
Point it to the middle of the exhaust valve. I did it years ago on a near stock motor....waste of time. I still have the washers laying around somewhere.....

They say you can get maybe 1-1.5% more power out of the motor.
 

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Posted by shade-tree (Member # 298) on :
 
ok, I'm dynoing my car this week.
I'm running short on time so I'll leave the spark plug indexing for last.

on my short list:

"typhoon" intake re-install (1-2 hours usually)
electric H20 pump re-install (who knows?)
custom belt routing for crank to alternator only (who knows?)
crank underdrive pully (15 mins. lol!)

given that the real world is like 2x to 3x my best estimates, It's gonna be close if I have my car set up right or not prior to my $50 A/F dyno session
 

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