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mid 20's Buick - Keeping plug wires clean

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I recently had an issue with my plug wires.  At night I was seeing a blue sparking effect around the plug wires.  Larry refers to this as the "blue light special".  These are 9mm cloth covered solid core plug wires with 400 miles on them.  I noticed it mostly on the coil wire after I pulled it out from under the spark plug cover, but I was also seeing it on the #1 spark plug wire with the spark plug cover off.   I was seeing flashes on my timing light with #1 being on the 1-6 line, but also flashes of 3-5 which would mean another wire sparking into the number 1 plug wire.  Another observation on this head design is that there is very little room under the cover.  It is difficult to keep the wires away from the hot insulator or the hot top of another spark plug as certain wires pass a plug to get to an end plug.  Here I worry about insulation burn thru.  In addition, there is some oil in this area (noted below the #1 plug), and my plug wires are not on the recommended oil list.  Not sure if this is leaking from the valve cover or the the pushrod tubes in the head itself.  

   I cut an insulator from .060 vinyl.  I originally used an 18" x 24" "for sale" sign, but then found some grey plastic.  The grey plastic bends where the vinyl sign would not.  On my drawing I show using the vinyl for the bulk of the insulator, and sheetmetal at the top to ensure no oil can get on the opposite side of the vinyl.  I also used some 3/8" vinyl tubing as additional insulation and oil protection for the plug wires.  I may even use some small tie wraps to the plastic backing to really ensure that no wires touch anything real hot.     

I still have to fit my coil wire back inside, but I think I have some better protection in place for the wires.




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To have such new plug wires leaking voltage like you described seems like  voltage saturation due to high resistance, possibly in the spark plug. I have experienced this before as I created a heavy buildup on new plugs during break in and tuning. I replaced the plugs and the voltage leak disappeared.

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Are you running a super 'HOT' coil on this engine?  I think someone on here said that these old 'mailbox' coils weren't nearly as good as the new ones.  When I changed out the plug wires on the '20, that thing bit me and my hand and forearm hurt for about 10 minutes.  When everything is right with these old ignition systems they will knock you on your a double s.  Been there done that!


Terry Wiegand

South Hutchinson, Kansas

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    I have a 6 volt coil that I bought from Bob's Automobilia, so I think just a standard coil.  When I saw the blue light special, I decided to lift the coil wire from the proximity of the starter generator top, and the coil wire did not shock me.  I thought this was a little strange, or maybe it was only firing thru a certain section of the coil wire.   I am running champion 3 com spark plugs.  These are NOS plugs without resistors.  I am running .030 gap.  I did have an issue with the Marvel carburetor spring in the air valve getting rusty and causing the air valve stick and to not close.  This made the car run very rich for a while and the plugs got covered in black soot.  They were wire brushed off, but they were very sooty.  Hugh  

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