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 Post Posted: Sun Jan 01, 2012 5:58 am 
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Your head has the plug at the top of the chamber so my comment isnt valid. My comment was directed to modern conventional plug position like a low down chevvy etc. The photo on the right is better but I would make the strap so its horizontal and over on the inlet valve side. The flame kernel doesnt grow as fast on the strap side of a plug and you want to grow the flame kernel toward the exhaust valve because thats the hottest gas area


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 Post Posted: Sun Jan 01, 2012 7:03 am 
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The flame kernel will grow the most efficiently in the direction of the hottest gasses so figure out where you want to put the strap that way.


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 Post Posted: Wed Feb 01, 2012 6:32 pm 
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I also have to index my plugs due to a high dome on my pistons and if I don't, BANG!!! =P~ THERE GOES ANOTHER PLUG!!!! ](*,)
I also have to index my plugs betwee 10 & 2pm, anymore or less and I nip the ground strap. Shrinker has this data to backup a few thoughts and I have been told also that if it(the ground strap) can be pointing more towards the intake valve, it will start the burn process a tad better.

I have had to buy (2) packs of Indexing washers of which each pack has 3 different thickness's and they are from B & B Performance thru Jegs and so far, so good. I have always indexed my plugs cause I always run big domes.

It takes me anywhere from the first try to trying every plug in up to 3-5 different boxes until I get the right plug, and indexed in the right location, and then I number the plug. I have to do this 3 times with each cylinder so I have them ready when needed, if needed. I have at least 6-8 boxes of 4 in each box so it takes a while to do this. Once done, it's done.

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 Post Posted: Wed Feb 01, 2012 6:50 pm 
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Hey Elky why dont you get or make an indexing tool. Its a lot faster and very easy that way.
Just to clarify the direction of ground strap etc. The flame kernel gets heat removed from it by the presence of the ground strap. So the growth rate in that direction is slower, its not that the flame has to go around a corner or a slipstream or anything like that its purely a heat removal thing.
Now we get into the chamber design. If the engine is efficient at scavenging the chamber the mixture quality is basically good even over at the exhaust valve side so when presented with that sort of engine the flame kernel will grow the fastest in the place where the highest heat is and thats around the exhaust valve. So you position the plug so that the flame grows toward the exhaust. If its has perfect vaporization then you make it grow toward the intake valve as that will always be, no matter what, the freshest place mixture wise. Over at the exhaust valve you will always get some residual exhaust and its a trade off as to if the exhaust is better for flame growth because of heat or not. If your engine has poor vaporization but good scavenge you make the flame grow to the exhaust valve. Sometimes the heat will facilitate vaporization in preference to the effects of contamination. A lot of what happens depends upon the gas species and their concentration, that's why gas benches are needed. Thats why you cant tune correctly off just AFR.
What you have to do is experiment, some engines make good worthwhile advantages of indexing others make no change. Its my job to figure out how the different factors interact together in an engine so that we can figure out how to change it for the better. Plug indexing and its effectiveness ties in with everything else and tells me the sequence of events and how they occur in the engine.


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 Post Posted: Thu Feb 02, 2012 1:23 pm 
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Hey Shrinker, I see a tool in the jegs catolog and it looks like a hex nut with a hole in the center, and I am not sure how it works as the description isn't very good. Is it a die type tool to cut more threads into the plug body? I need to locate one and see how it works. Thanks for the info.

John

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 Post Posted: Thu Feb 02, 2012 6:20 pm 
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Thats a sparkplug indexing tool. How you use them is this way; You index a set of plugs by using washers etc for your engine and you put each indexed plug into the tool and mark it with the cylinder number it fits. Then you just get plugs straight out of their boxes and thread them into the tool and where they finish up is the cylinder they will fit, or you figure out indexing washers etc to make them fit. Its really easy and quick. All you need is a block with a sparkplug thread in it.


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 Post Posted: Tue Mar 06, 2012 7:43 pm 
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boy, am I laim!!!! sorry for the really late reply, and thanks for your info and reply Bruce. I will look into this tool and give it a shot, takes just too darn long to get 8 plugs to fit in my engine. ;-)

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 Post Posted: Wed Mar 07, 2012 8:00 pm 
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If you run the gasket plugs, not the taper seat plugs, you have to account for the gasket washer being flattened when they get torqued. So if you aren't running taper seat plugs, you will have to flatten the gaskets before using the index tool. I use a spare head to install new plugs in before indexing. I guess you could put the index tool in a vise and tighten the plug in it to get the washer flat, but I've never done it that way. Does this make sense to anyone?


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 Post Posted: Fri Mar 09, 2012 9:25 am 
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webermaniac wrote:
If I'm not mistaken NGK in their plug installation instructions state that washers take 1/4 of turn to go from new to fully compressed. Might be useful to just add 1/4 turn to the indexed position leaving the washers intact before actually installing plugs into the engine.

Yeah, I've tried that in the past and didn't really like it. I had a narrow range back then, 11-1, and judging the 1/4 extra just seemed to make it more tedious. I have more room in my current engine so I think I'll try it again. Thanks for reminding me.


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 Post Posted: Fri Mar 30, 2012 7:35 pm 
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Ron Gusack wrote:
If you run the gasket plugs, not the taper seat plugs, you have to account for the gasket washer being flattened when they get torqued. So if you aren't running taper seat plugs, you will have to flatten the gaskets before using the index tool. I use a spare head to install new plugs in before indexing. I guess you could put the index tool in a vise and tighten the plug in it to get the washer flat, but I've never done it that way. Does this make sense to anyone?


Yes. When I used to index, I found that torquing each fresh plug was most important. I've thought about torquing against the index tool as you describe, but don't recall if I ever have. Always seemed like it was safer to torque in the iron heads.


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