This one has been developing in the (much bigger) US community for some time.
There are two separate issues:
1) Cracked insulators, which seem to occur on certain engines, notably IIRC the SR22 turbo.
2) The internal resistors, which go almost open circuit (I have a pile in front of me) and force the magneto to generate enough volts to jump right across it, which doesn't do the magneto and the ignition harness much good, as well as generating a weak spark which can impact engine starting and high altitude performance.
Champion have just released a letter blaming the engine operation 
Local copy here
They are not commenting on the dodgy resistors, of which I have a pile right here, all nearly open-circuit. Here is a couple
These are not user-replaceable so the $80 spark plug is scrap.
I used Champion RHM38S and having found a near-100% resistor failure rate I have moved to Tempest's equivalent: URHM38S. They work perfectly, and monitoring their resistance shows no significant drift, but do require a different (or modified) plug spanner.
The Tempests are cheaper, too.
Peter, i agree 100%.
Pulled out 12 Champions massives out of our SR20 after 450 hours (and 4 years). Measured all resitors and NONE showed anything on the dial, meaning, they´re open circuit. Replaced them with TEMPEST fine wire (they don´t have that insulator cracking problem due to a different insulator compared to the champions). Engine runs now a lot smoother, even at LOP operation in the flight levels.
To all out there: pull out the champions, regardless if massive or fine wire. Insulator cracking causes detonation and that will kill your engine in seconds, preferably after takeoff or at high power settings!
A broken insulator is a very serious issue which can damage the engine - depending on if and where the piece gets stuck...
Actually, having read a lot about this problem on the US forums, I wonder whether the broken insulator issue is confined to the longer-reach plugs used on that SR22 (Conti) engine. My RHM38S plugs are much shorter. But also turbo engines work much harder - 75% power climbs to cruise (which you do with a turbo because that's what you paid for ) are completely different to a non-turbo engine.
But the "nearly open circuit" resistors are a universal issue with Champion fine wire plugs. I did loads of tests on them with a high voltage tester (we have one at work) up to 4500V and the ones which show open circuit (usually this means > 20M ohms) with a normal digital meter do all actually start to conduct at a few kV, but that is a few kV extra which the mag has to generate before you get a spark.
I tested two batches of the Champion fine wire plugs, one bought in 2002 (which fortuitously I had kept) and one bought in 2008, and both (2x12 plugs) had similar behaviour. So this is a long term problem at Champion which they have got away with through pure luck, and who really goes around measuring plug resistors?
A quite amazing statement from Champion. I wonder what they expect it will do to their reputation?
This month's Aviation Consumer has a very intresting article about it...killing Campion.
Ben
These big companies don't give a damn.
They have not yet realised how effective the internet is, and they hope to plough on regardless. They are supported by the distribution/reseller pipeline which makes money selling their products no matter what happens.
If you are after some amusement and don't mind reading a bit, here is an example from another bit of aviation.
Honeywell have known about that for over 10 years.
This month's Aviation Consumer has a very intresting article about it...killing Campion.
Interesting... I don't have a current sub to AC but I do recall them writing a load of "warts and all" articles. Some of them were so hard hitting they suprised even me
To my knowledge this is not a Cirrus specific problem, but it appeared first in the Cirrus TN fleet. It has been encountered in T and NA Cirrus, Corvallis, T310, Bonanzas, and Barons. But obviously all with the RHB32S fine wire plug (in Conti engines). From what i read it also is an issue in a Lyco engined PA-46-350P.
The Champion letter was a retour to a SB from Tornado Alley Turbo, but Cirrus recently issued their own SB, recomending against Champion fine wire plugs.
Well I just replaced all the massive electrode Champion plugs in the PA-46 with fine wire but still from Champion. The shop doesn't believe there is an issue with the fine wire.
It's your engine sir :)
Just out of interest does your 'shop' have an internet connection? ;)
does your 'shop' have an internet connection?
Have to admit... I was going to say the same!
I am happy to show my useless Champion fine wire plugs to anyone. Sure, the D3000 Bendix magneto in the TB20 has enough power to just flash right over the whole resistor if necessary, but that isn't quite how an ignition system is supposed to work
