The copper indexing washers that are sold did not work well for me. These copper washers kept letting the sparkplugs become un-torqued. I would urge just buying enough sparkplugs to find 'by chance' ones that index properly.

It is my opinion that indexing (and big gaps)
work best when combustion conditions are bad....
so you get the best effect at
part throttle highway cruise (better mpg)
very high rpm
and when the engine is cold after startup.

With both indexing and bigger gaps
you are trying for an increase in
"real world"
igntion timing.

What I mean by that is
instead of advancing the ignition timing by the computer settings,
you improve combustion speed,
commonly called
'fast burn'.

On a 5.2/5.9 V8 the factory pcm ignition timing at wide open throttle
and 3000 to 4000 rpm
is typically about 24 to 28 degrees before top dead center.
{can be even less if the 'Death Flash' has been applied}

Engine shops like KRC, Revsearch and Shady Dell report that
34 to 36 degrees on Magnum heads
gives optimum power on high octane gasoline
in the 94 to 96 octane range.

What this means to me is that some gains can be had
if you can increase 'fast burn'
rather than increase electronic ignition timing.

The gains aren't great,
but considering that automakers spend a year of Research & Development
to get even a 1% gain in engine efficiency
indexing is a way to 'gain a few years'
with just a few hours work.

The dual sparkplugs on the 5.7 Hemi
is another strong hint
that some modest gains are available
if 'fast burn' can be enhanced.

If someone wants to go further testing indexing on Magnum cylinder heads
using a spark voltage analyser
and maybe a 'Colortune' plug
might give valuable results
that all could share in:

http://www.etoolcart.com/index.asp?P...mp;ProdID=5073

http://www.rdent.com/pages/tools.html

 

HankL,
You bring up another interesting point in the dual plug scenario of the hemi. Obviously the engineers think there is something to be gained by a multi-spark. They are just going about it in a different way than the single plug-multi-spark (MSD) type system...
I'm just sayin'!
WC

 

good stuff guys
i am gonna have to do this next time i change my plugs

 

I appreciate the info here guys, very useful. Next time I do a tuneup ( coming soon ) i'll try the indexing method as explained above.

Here's a question for the plug experts, if I was to set the gap a few thousanths of an inch lower than base minimum of recommended gap would that help in reducing the gap of the plug from expanding too high as time goes on. Ive seen with past cars that Ive owned that the gap in the plugs seems to increase in time, thus my gap was now past the recommened gap. I dont know if that was a normal thing or if the plugs were just geting too hot thus expanding the ground strap from the electrode or if was just because they were Bosch Platinum's. But I think I read in another post on this topic that bit higher of a gap would help create a faster burn but maybe I read that wrong.

 

Mopar Crazy,
Yeah, the gap gets slightly larger over time. That's why you are supposed to check, clean, and adjust periodically. You'd be shooting yourself in the foot though to start off with an undergapped plug and hoping it "catches up". Performance will suffer until it does and it may never get to where it should have been all along.
WC