I would have though the usual fault was interlayer discharge within the HV
windings. You can do a simple comparative test with just a neon and 100 Meg
of resistance dropper. Strongest orange discharge glow ok , poor or non
existant glow , bad
I would think that oil would be an insulator.
It's probably defective coil construction or problem with the plastic
potting,like cracks admitting moisture.
Maybe aftermarket coils would last longer.
If you want to use your o'scope,just lay your scope probe next to the
coil,it will pick up the signal.no need to make any direct connection.
I've done it with flybacks in TEKTRONIX equipment.
If there's a problem,you'll see a clipped waveform.
One more thing to try; Dick Smith's flyback tester.(FBT)
the same guy who created the marvelous DSE(now Anatek) ESR meter.
--
Jim Yanik
jyanik
at
localnet
dot com
The easiest thing to do is swap the coils and see if the problem moves
with the coil. I agree with Jim, it is most likely a potting problem and
an aftermarket coil will resolve it.
Tom
You kind of are over thinking this.
I have a 97 Lincoln with the coil-on-plugs, with the associated ocassional
oil leak, but you are better off getting a OBD2 tester and let the onboard
computer tell you the bad ones.
It'll spit back the exact "cylinder misfire on ...".
Off hand, failure of them I don't think is related to the oil problem. I've
had two of those coils fail so far and the last one was dry as a bone even
though it was drivers side closest to the firewall and the 1st plug closest
to the radiator was completely submerged, that one was fine.
I just sop out the oil with twisted paper towels every once in a while (2 or
3 years) and just keep on going.
Unless you are topping out the oil every time you fill up, it's probably not
worth bothering to fix, if it can be fixed at all. I've seen guys say they
went through the trouble of replacing the valve cover gaskets with the
problem returning in 6 months or so.
Seems to me like it's a few drops a month which eventually fills up the
chamber the plug sits in, but like I said, once in a while just sop out the
excess with a twisted paper towel and it'll be fine.
The replacement made-in-china coils are only around $30 anyway.
Also if you haven't stumbled into it, try this site:
Although it's for Mark VIII owners (which was stopped in 1998), there are
quite a few discussions about this matter on there that might be helpful.
-bruce
b...@ripco.com