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index spark plugs

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index spark plugs

Postby jdgreentruck » Sat Jan 02, 2010 8:09 pm

is it worth indexing plugs ?

also run Non- Projected tip or Projected Tip
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Postby curtis reed » Sat Jan 02, 2010 10:24 pm

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Postby ProPower engines » Sat Jan 02, 2010 11:17 pm

In the big picture its the attention to the smallest details that make or break the performance.
Sort of like the brand of race plug Vs street plug. One is better that the other for a given application.
My vote is yes. Do it!
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Postby rally » Sun Jan 03, 2010 12:20 am

I never saw any improvement at the drag strip indexing plugs. Oh i still do it but no gain. I dont shim, i just mark the plug and find out which plug has the open end facing down on the piston.
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Postby ProPower engines » Sun Jan 03, 2010 1:41 am

I have seen improvment on alky engines that run a mag.
plug gap is only .020 and with out indexing correctly it would not run right on the dyno. ](*,)
Indexed the plugs and made a full pull to 8200 with out missing a beat.
It may have a lot to do with the chamber and how that affects the burn but in this case they were RHS 235's on a 360 sm blk . vettex mag and it would not get over 4600 with the plugs "just installed". :roll:
Not that it matters but they were AR-133 race plugs.
Made me a total believer! :)
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Postby lun40119 » Sun Jan 03, 2010 11:04 am

This is a Dart Chamber in a Pro 1 for a BBC. They have moved the entry of the plug as far up in the chamber, I would think it would be very important with cylinder heads that have a chamber similar to this.
Image

The spark would be pretty badly shrouded by the ground strap in this head. Maybe if I get time on the dyno this March, Ill flip a set of plugs in upside down once and see.
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Postby bigjoe1 » Sun Jan 03, 2010 12:29 pm

Didnt they tell you that you are supposed to grind away all the exposed threads in the chamber ?? If not, just dissregard this little speed secret


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Postby Wolfplace » Sun Jan 03, 2010 12:42 pm

bigjoe1 wrote:Didnt they tell you that you are supposed to grind away all the exposed threads in the chamber ?? If not, just dissregard this little speed secret


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Re: index spark plugs

Postby Rommel Racing » Sun Jan 03, 2010 1:42 pm

jdgreentruck wrote:is it worth indexing plugs ?

also run Non- Projected tip or Projected Tip


The only time I feel indexing plugs makes a difference, is when you don't have a choice :lol: a couple of friends, have some big domes on their pistons with witness marks where the piston had hit the ground straps....so for them it is worth it to index their plugs.

On my motor without interference issues, I saw no gains when I tried indexing :? You should try it and see for yourself, results may very.

As for the plugs, most guys are running non-projected plugs in race motors, less chance of the ground strap becoming a glow plug.
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Postby lun40119 » Sun Jan 03, 2010 1:42 pm

Here is what my chambers look like when I bolted them on Joe. These are an SBC. The BBC's are what they looked like when we took them out of the box.

Image
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Postby bigjoe1 » Sun Jan 03, 2010 3:17 pm

TOO BAD you missed that


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Postby lun40119 » Sun Jan 03, 2010 6:05 pm

Lucky for me they are back off. You worried bout detonation? Didn't show any signs of detonation at 38° total, but et best at 36°.
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