Procedure for Indexing Plugs

[Texasstar]

What is the best way to index plugs?

 

[Sonreir]

You mean read them after a plug chop?

 

[Texasstar]

No pointing the halo in the correct direction toward the intake and matching both plugs.

http://www.musclemustangfastfords.com/tech/0207mmff_tech/index.html by David Vizard tells why the plug mod works.

"We are indexing the plugs on my drgaster for a couple of reasons.

1. To make sure there are no problems with piston interference (as was already mentioned)

2. Also to try to get the flame path the same so all the cylinders match as much as possible. We are running mechanical fuel injection and having all the cylinders as close as possible helps sort out the bugs and makes charting tuneing changes easier.

When we went to a Magneto we found we had to close up the plug gap for better performance. Follow the manufacturers advice on your plugs or with your distributor if you are running a newer one."

 

[AlphaDogChoppers]

No, he is talking about adding shims under the plug gasket so that the electrode is pointed in the optimal direction.

It's a dumb waste of time for anything but an all out drag racer.

 

[Texasstar]

No, he is talking about adding shims under the plug gasket so that the electrode is pointed in the optimal direction.

It's a dumb waste of time for anything but an all out drag racer.

^1 top dog! Hell yea we want to waste time! waste it right off the clock. you just confirmed the importance of indexing. However I want to know how to do it without shims so not to lose the minuscule compression. I have been told the devil is in the details and so is going fast...

 

[Hoosier Daddy]

You draw a line on the ceramic with a sharpie that aligns with the electrode and compress the sealing washer until it is pointing in the direction you want, may need to pick up a dozen or so plugs to get it dead nuts right right.
I have heard of guys trimming the ground strap closer to the 90 bend, exposing the electrode and gapping the stub to "unshroud" the spark. I think that would be much easier.

 

[TomTerrific]

Iridium spark plugs have been shown to work well with archaic combustion chambers and weaker old ignitions. The ND iridium has an even smaller .4mm electrode compaired to the NGK .6mm.

Usually three different nose lengths for the same heat range plugs. Standard, projected and extended. It is generally accepted that the further into the combustion chamber the initial flame kernal starts, the better the burn. Some engines can use the next extension but it isn't just a simple as trying. It really has to be checked. Best to let someone else experiment unless it is planned to check clearance.

You can get indexing washers from Michael Morse at Vintage Brake. Call, as it's a one man show but the guy knows everything.

The indexing is used to clear the valves on a souped engine and correct some sort of mixture motion problem in the CC. Convention says point the gap toward the intake valve. Sometimes the indexing is best toward the exhaust valve to speed the initial burn and help with detonation. How would one know which way to point it? I like your idea of at least having the gap pointing in the same direction in all cylinders.

Probably the easiest way to get better spark plug performance is to try Iridium plugs.

I'm new on this forum but here is a good read worth mentioning again.

www.strappe.com/plugs.html

Tom

 

[Texasstar]

You draw a line on the ceramic with a sharpie that aligns with the electrode and compress the sealing washer until it is pointing in the direction you want, may need to pick up a dozen or so plugs to get it dead nuts right right.
I have heard of guys trimming the ground strap closer to the 90 bend, exposing the electrode and gapping the stub to "unshroud" the spark. I think that would be much easier.

thanks Hoosier Daddy! Did you see the David Vizard article I referenced above? He said the same thing and posted this picture. The only difference was to curve the ends of the ground. Now Teazer has told us that the key to going fast is optimization so we are looking for every little place to optimize. Now as you may know we have started with 12 whp with a basically stock CB motor. We are currently at 15whp and are looking for more little gains for our next dyno run. What I want to teach my son is to take care of the small things and then the big things will take care of themselves. As Mr. Vizard said the good plug wires will increase performance and we FELT a significant increase in acceleration and throttle response when we took off brand new cheap solid core plug wires and install Taylor 8mm spiral core silicone wires. We are also seeing spark jump from the points to the band Mr. Vizard said they saw significant gains by prepping the plugs for nitro as you have suggested. I would like to see the difference between the two on a dyno. I would also like to know if indexing makes a big difference on the dyno with the plugs prepped for nitro??? Thanks for your input it is invaluable! Godspeed to all in DTT!

 

[Texasstar]

Iridium spark plugs have been shown to work well with archaic combustion chambers and weaker old ignitions. The ND iridium has an even smaller .4mm electrode compaired to the NGK .6mm.

Usually three different nose lengths for the same heat range plugs. Standard, projected and extended. It is generally accepted that the further into the combustion chamber the initial flame kernal starts, the better the burn. Some engines can use the next extension but it isn't just a simple as trying. It really has to be checked. Best to let someone else experiment unless it is planned to check clearance.

You can get indexing washers from Michael Morse at Vintage Brake. Call, as it's a one man show but the guy knows everything.

The indexing is used to clear the valves on a souped engine and correct some sort of mixture motion problem in the CC. Convention says point the gap toward the intake valve. Sometimes the indexing is best toward the exhaust valve to speed the initial burn and help with detonation. How would one know which way to point it? I like your idea of at least having the gap pointing in the same direction in all cylinders.

Probably the easiest way to get better spark plug performance is to try Iridium plugs.

I'm new on this forum but here is a good read worth mentioning again.

www.strappe.com/plugs.html

Tom

Tom first of all welcome to DTT! Sonreir suggested the following on our build string, "If you can find spark plugs with multiple side electrodes, give them a try, too. Those extra electrodes take up a little volume in the combustion chamber and may get you a couple of extra tenths of compression."

Sonreirs advice was floating around in my head when my nephew suggested indexing the plugs. He gave the same advice on buying multiple plugs to get them indexed and as you suggested to use iridium plugs. Now the next question I asked was what about indexing multiple side electrodes. Your advice gave me something to chew on. If we can use a longer nose lengths then the washer issue may be not as much a problem with reducing the combustion. I will give Michael Morse a call...I am also looking for Michael Moore of Eurospares if anyone has his number. Thanks!

 

[acm177]

Be mindful of the clearance between the valve and the electrode when selecting a different plug.
I was fortunate to index my plugs while the head was off, and noticed that my oversized valves were much closer to the electrode. May not be a concern on a stock sized valve.

I bought some shims for my plugs via McMaster-Carr.
http://www.mcmaster.com/#standard-shims/=nbimot

 

[Texasstar]

Be mindful of the clearance between the valve and the electrode when selecting a different plug.
I was fortunate to index my plugs while the head was off, and noticed that my oversized valves were much closer to the electrode. May not be a concern on a stock sized valve.

I bought some shims for my plugs via McMaster-Carr.
http://www.mcmaster.com/#standard-shims/=nbimot

thanks Acm177...y'all are the greatest!

 

[TomTerrific]

I never took to the multiple elctrode plugs. It seems to me that the extra electrodes would shroud the spark and do exactly the opposite we are trying to accomplish.

Back in the 70's there were electronic ignitions just coming out and replacing points in cars and bikes. i read about GM's HEI and how powerful it was. Powerful enough to kill a mechanic. Could have been Hot Rod Magazine, I read testing where as the spark gap was increased, there were benefits. The point where the benefits tapered off was .045". Buick had an engine that called for .080" spark gap!

My 1971 Norton sucked as a reliable starter. I'd either flood it or it was too lean to fire. I saw an article about car coils on bikes so in 1975 I ditched the 6volt Lucas coils and the ballast resistor and installed some 12volt car coils with a suitable resistor. I could see the spark was more powerful so I increased the gap to .035" because that was what a car used. The Norton became an easy first kick starter. Flood it with the ticklers and kick. The little fine off idle jetting problem that I struggled with seemed solved also. At the time i credited the powerful spark but now I know it was as much the increased gap allowed by that spark.

Focus on the size of the initial flame kernal and not to quench that initial kernal. I think this is one thing the iridium plug is good at.

Tom

 

[Texasstar]

I never took to the multiple elctrode plugs. It seems to me that the extra electrodes would shroud the spark and do exactly the opposite we are trying to accomplish.

Back in the 70's there were electronic ignitions just coming out and replacing points in cars and bikes. i read about GM's HEI and how powerful it was. Powerful enough to kill a mechanic. Could have been Hot Rod Magazine, I read testing where as the spark gap was increased, there were benefits. The point where the benefits tapered off was .045". Buick had an engine that called for .080" spark gap!

My 1971 Norton sucked as a reliable starter. I'd either flood it or it was too lean to fire. I saw an article about car coils on bikes so in 1975 I ditched the 6volt Lucas coils and the ballast resistor and installed some 12volt car coils with a suitable resistor. I could see the spark was more powerful so I increased the gap to .035" because that was what a car used. The Norton became an easy first kick starter. Flood it with the ticklers and kick. The little fine off idle jetting problem that I struggled with seemed solved also. At the time i credited the powerful spark but now I know it was as much the increased gap allowed by that spark.

Focus on the size of the initial flame kernal and not to quench that initial kernal. I think this is one thing the iridium plug is good at.

Tom

Thanks Tom we will give it a go!