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Old 14th Apr 2012, 13:54
  #15 (permalink)  
peterh337
 
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I have another data point... rather interesting.

I've pulled out the six top plugs from the engine and measured them. They all measure 15-25k. I have no reason to think the six bottom ones will be any different and since I swap them all round every 40 hrs or so, it would be statistically astonishing if they were. These plugs were fitted in 2008 and have done ~400 hrs. Note the previous set, all ~1M, had done 700hrs.

So we have these possibilities:

1. The resistors in these six were always 15-25k and never changed.

2. The resistors in these six were say 3k and they degrade gradually, taking a jump from a few k to 15-25k before 400hrs, and then a big jump to say 1M between 400hrs and 700hrs

3. Champion changed the resistor mfg process between 2002 and 2008

4. Some combination of the above

My money is on 3. definitely, and 1. possibly.

I numbered the plugs and will recheck them at the next check, in ~20hrs' time. That WILL be interesting.

I didn't bother testing them all with the 250/500/1000V insulation tester because values like 20k just read as close to zero.

It would be really interesting to get a brand new RHM38S and measure it. But anybody who does that is going to blow away ~£95 (Transair price) because they come in sealed packages
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