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A "Spark" of Inspiration

Updated: Sep 12, 2023

A few weekends ago, while giving the cars their usual start & warm up, I decided to take a manometer to each of the carb stacks on the "Clunky Panda" to measure and compare vacuum across all 4 - #3 was the worse BUT why was she idling so well? Did a quick audio test at each horn opening and again, #3 was the odd man out. The ignition setup uses 4 Coil on Plugs - so as it idled, each connector was disconnected then reconnected, one at a time to observe an obvious drop in idle. Loss of spark at #'s 1 and 2 displayed a noticeable "droop" in the engine. When it came to #3 - you guessed it, no change in engine idle speed whatsoever. The engine showed the same lethargy when spark was pulled from #4.

Upon closer inspection, the CoP on 3 showed to have pivoted to one side of center in the opening it occupied in the valley cover. Messing with it further revealed that it had loss contact with the spark plug. Well, unbolted the coil from the cover, re-centered and made sure that it was dead-on the plug this time and tightened her down. Fired up the "Clunker" again and she was already singing a new note. Would you believe, the ol' girl had been limping on just 3 cyls for longest time. While she idled, I decided to fool with the #3 coil and sure enough, as you pivoted it on that one bolt that held it in place it eventually slipped off the plug again. The diameter of the coil tube being smaller than the hole in the stock valley cover it occupies was the main problem. Well, nothing some 3D printing can't fix, right? We'll let the pictures tell the rest of the story.

"Moon phase 1..." (The "Clunker" needs a new valley cover)

"...phase 2..."

"...phase 3..."

"...and phase 4."

"Solution time"

"It's a snug fit...someone else spy a crest?"

"Problem solved! Those coils are all dead-center and aren't going anywhere, now. That valley cover is still ugly, though." *For those interested:

  • The TPE material, at 80% infill for each of the coil adapters won't start to deform until 374F

  • Programmable ignition - Megajolt by Autosportlabs

  • The 2 wire Coil on Plugs are commonly found on the 1MZFE engine - preferably the non-waste spark types.

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