Anything to gain from indexing spark plugs?

[flatsixrider]

I understand the principle, just am not sure there is anything to gain on the Valkyrie from indexing.  Anyone done it with good results?  Waste of my time? Looking for thoughts/experiences. TIA!

[Brad]

http://www.valkyrieforum.com/forum/tech_archive.cgi

do a search in the archives, some good threads back in 07 on this subject
 

[Madmike]

There may be an advantage to these if they are available in the correct size and a good heat range. 

http://www.boschautoparts.com/Products/SparkPlugs/Platinum4

I've used plugs with multiple electrodes but on natural gas fueled engines where the fuel is a little tougher to ignite than gasoline.  These engines also used a rich rail that fed a pre combustion chamber or precup, the spark ignited the charge in the precup which is indexed to the cylinder, there are holes in the precup that the flame comes out of to ignite the main fuel charge in the cylinder.  These particular engines were 8.25 bore and 10" (?)  stroke, they put out about 1800 HP at 900 RPM, the Champion plugs that we used were over $100 each, 12 to a change.

Bosch claims some savings and improved efficiencies with the plug in the link.  Whether they are real and costs can be justified would have to be proven.

[YardBoy]

I used to index on some of my drag racing motors, did not hurt anything and may have gained a mouse power or two.     

 

[mikehallbackhoe]

I have tried indexing the plugs on the valk, it is a waste of time. I noticed no difference

[Chrisj CMA]

I index my spark plugs after a friend encouraged me to do so.  The benifits are miniscule I agree, but it also depends on how the plugs would be oriented without the indexing.  For the one that had most firing into the chamber as opposed to into the wall, well indexing may not even e needed.  For me, the first time 4 out of the 6 plugs were aimed directly at the cylinder wall, when I indexed them toward the combustion chamber I noticed easier starts, smoother idle and maybe a crisper throttle response, but I do know some of that can be psychological.

Bottom line if the plugs arent firing into the middle of the chamber, you will notice a slight improvement once you correct that.  It is by no means necessary or the latest free HP gain to rush out and do......just a tweek to the worlds greatest motorcycle engine

[flatsixrider]

I index my spark plugs after a friend encouraged me to do so.  The benifits are miniscule I agree, but it also depends on how the plugs would be oriented without the indexing.  For the one that had most firing into the chamber as opposed to into the wall, well indexing may not even e needed.  For me, the first time 4 out of the 6 plugs were aimed directly at the cylinder wall, when I indexed them toward the combustion chamber I noticed easier starts, smoother idle and maybe a crisper throttle response, but I do know some of that can be psychological.

Bottom line if the plugs arent firing into the middle of the chamber, you will notice a slight improvement once you correct that.  It is by no means necessary or the latest free HP gain to rush out and do......just a tweek to the worlds greatest motorcycle engine

That is about what I expected.  no reason not to try and get them in the best place possible.  I would think with 6 to go around, chances are good the can be reasonably well oriented with no shims.   Might as well do it if I am going to replace the plugs anyway. 

Thanks!

[Fathertime]

  Ok, I'll bite,,,

  What is indexing?
  How does one index?

[Chrisj CMA]

  Ok, I'll bite,,,

  What is indexing?
  How does one index?

Basically what you are doing is aiming the "spray" of the spark plug (ideally) toward the intake valve, but at least into the cumbustion chamber.  Because of the design of the standard plug it does have a directional ignition when it fires.  Because of the angle the plug enteres the chamber, it it possible to have the gap pointing directly into the wall therefore difusing the spray.

By controlling where the gap points you are indexing the plug. 

This can be done a couple ways.  First you have to mark where the gap is.  I use a permanent marker and make a black dot on the very top of the porcelin where the gap is so I can see that mark once the plug is tightenend.

Then just by juggling plugs around I was able to get them all at least pointing into the chamber.  THe second way is to buy indexing rings.  Copper washers that you can put under the plug to stop its travel early to change the index.  I havent needed to do that yet

[R J]

If you are not a professional Drag Racer or a hot shot circle burner, I'd assume you have better things to do with your spare time.

When we run a Super Stock Drag Car, 426 Hemi Sport Fury,  we indexed the plugs for .0011 less ET, and no change in MPH.  Sox & Martin still run our butt in the ground.   Think we beat them once with a hole shot.  At our own track, we won a lot of Trophies.

When we switched over to Alcohol Dragster, it then made a remarkable difference...  Same engine.........

[Chrisj CMA]

If you are not a professional Drag Racer or a hot shot circle burner, I'd assume you have better things to do with your spare time.

It takes 20 minutes or less extra time while changing spark plugs and there is a slight but tangible improvement.  If that isint worth it to you, then dont do it.  I think its 20 minutes well spent and yes, Im semi-retired so I have not much else to do with that 20 minutes one night every 50K miles or so.