Iridium?

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In magneto fired recip aircraft engines we swap the plugs around in the firing order to even out the plug electrode wear, extending the life of the plug, depending on engine type this occurs for some at 25 hrs. or for most at 50-100hrs. The plugs also require grit blasting and regapping at the same time. On a single coil/twin lead ignited bike one would just swap the plugs left to right every so often to accomplish the same evening out of wear or if your cables and routing allowed, simply swap them left to right and don't mess with the plugs or just do like Jim C. said and run dual platinum capped plugs and forget about it.
 
Many of us spend thousands of dollars on rods, pistons, headwork to get better performance. Why not run the best, longest wearing plug possible......only costs a few dollars more. In the USA, Iridium plugs are available for very cheap I've found.

I installed a set of Iridium plugs in one of my motors and I did notice a better, cleaner idle and lower RPM performance.

Would be interested to hear if anyone else has experienced the same?
 
I run them in my '73 750 with Tri-Spark and, as I recall, they are recommended by Tri-Spark. I also run them in high boost turbo cars. They are also useful as a diagnostic tool - to confirm a weak ignition - if a miss stops after installation of a fine wire plug, then look to wires/coil/etcetera.

As for spark plug blasters/cleaners, I have one and during my two stroke days, I used to use it a lot. I found however that I had to be very careful and use a spark plug light with magnification to look and make absolutely certain that no particles of grit remained at the root of the insulator. During cleaning particles get jammed between the insulator and the plug casing that the compressed air fails to dislodge. They will, under combustion, come loose, so I used to use a needle to pick any particles out.
 
I've been using the Denso IW22 (5307) for the past few thousand miles. No issues (w/Power Arc ign)
 
I ran my 750 race bike on the dyno and found about a horsepower simply changing from B8ES to the equivalent iridium plug. The dyno man reckoned that could be a sign of a weakness somewhere in the ignition as xbacksideslider mentioned.
 
comnoz said:
xbacksideslider said:
Don't know if it is true or not but I recall it said that the original fine wire platinum Champion plugs that were popular with the old magneto points ignitions on the Yamaha two stroke twins operated as a "fuse" in that - it was claimed - the platinum would melt, increasing the plug's spark gap, and thus degrade the spark, thereby reducing heat, just before the moment that the engine would melt a piston or seize.
Click to expand...

That is a new one to me..... :?
Click to expand...

Anything, including fancy oil, that stops 2 strokes seizing is a new one on me :?
 
Thanks for the 'real world' feedback on this.
As with most marriages of modern tech with our old machines, it is not always as simple as first appears.
I think I will give the iridium a go.
Got new leads coming from Moroso and think they will match up well.
 
I had great luck with the NGK BP7EIX iridiums with my old worn Amals, old coils and stock alternator. After I upgraded to Premier's, 3 phase, replaced a failing coil (which died right after the 3 phase install) and new SS solid wires they burned scary clean. I went back to the NGK BP7ES. Only pulled the plugs once since then and the look great after about 1,000 miles. The iridium helped mask some issues, but you might want to watch the heat range. Hope this is helpful.

Pete
 
Deets55 said:
I had great luck with the NGK BP7EIX iridiums with my old worn Amals, old coils and stock alternator. After I upgraded to Premier's, 3 phase, replaced a failing coil (which died right after the 3 phase install) and new SS solid wires they burned scary clean. I went back to the NGK BP7ES. Only pulled the plugs once since then and the look great after about 1,000 miles. The iridium helped mask some issues, but you might want to watch the heat range. Hope this is helpful.

Pete
Click to expand...

PowerArc (C5) tech support actually recommended trying heat range 8 for the Iridium.
 
After seeing mine I believe it. I'm running a Boyer analog @31 degrees. That's the reason I want to put a degree wheel on mine to double check timing marks on my rotor. I'm trying to eliminate one one variable. Does Power Arc require any resistance in the high tension side, I run my Boyer w/ solid wires, plain cap and non-resistor plugs. It drives my cell phone and handheld wireless induction tachometer crazy at times.
Pete
 
Deets55 said:
After seeing mine I believe it. I'm running a Boyer analog @31 degrees. That's the reason I want to put a degree wheel on mine to double check timing marks on my rotor. I'm trying to eliminate one one variable. Does Power Arc require any resistance in the high tension side, I run my Boyer w/ solid wires, plain cap and non-resistor plugs. It drives my cell phone and handheld wireless induction tachometer crazy at times.
Pete
Click to expand...

I do not know anything about the Boyer, but PowerArc definitely recommends resistance plugs and the Moroso wires as supplied by Fred at Old Britts.
 
I think the digital units don't like the interference created by non-resistor HT loops, the analogs seem to tolerate. I emailed Boyer before I put everything in place they were OK with it. Works for me.
 
It should be said, IIRC, that the Denzo iridiums have built in resistors and you may already have resistors in your plug caps. Whether two resistors in series is a negative, I forget.
 
backslider,
Don't know about Power arc, but everything else I ever read said only one type of resistor is needed. Either wire, cap or plug.
Pete
 
I've come across statements in venders of single fire ignitions that the reverse polarity plug loses ~15% spark energy, though can't see why if same current passing the gap in same time as the other. Both plugs resistance is always in same path which sets the voltage it take to spark. Has it occurred to anyone to grind the reversed plug hook to more easy discharge point? Check with Powerarc for plug type to use.
 
Correct, resistor caps, wires, or plugs, but don't iterate. I had this specific conversation with representatives of both Sparx and Trispark. Both were clear - total 5K (in my case) ohms resistance in the entire system.
 
Yes, 5K max and the ND Iridiums have that built in.

Packard 440 wire IIRC, is silver plated fine stranded copper, and NGK sells a non- resistor cap but their resistor cap looks the same and is more commonly stocked. Also there are high temp silicone rubber caps that are sold with/designed for use with crimp or solder type internal plug clips
 
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