Bill, there are 2 possibilities. First you will hear from many people that you should never sandblast plugs. The reason is that the porcelain is pitted and the glaze on the plug is broken and then the plugs can embed carbon. The plugs can then track carbon and the spark will travel down the carbon track. On fine center wire plugs blasting can round the electrode which increases the voltage needed to fire the plug. Both conditions are bad, tracking is the worst. Pull your plugs and look for what appears to be a pencil line down the insulator. That is tracking. It likes to hide in the area near or under the sidewire which doesn't clean up as well when the blasted.
Bill Jepson
On Sep 3, 2012 8:47 PM, "Bill Bradburry" < bbradburry@bellsouth.net> wrote:
Has anyone ever noticed a hiccup
associated with sparkplug SAG? I have a hiccup that is occurring at
random intervals from seconds to several minutes. Sometimes it is pretty
mild and sometimes it shakes the plane! I also seem to be down in power
and I am beginning to suspect plug SAG. I have 38 hours with the Iridium
plugs plus a lot of time over the years of running the engine before
flight. I had a couple instances of flooding which required that I take
the plugs out and sandblast them to get them to fire. Just drying them
out didn’t work.
Thoughts??
Bill B
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