The Ford Barn

Bored&Stroked · 10-24-2023, 08:03 PM

One of the challenges can be that distributor machines don't test anything to do with the secondary side of the equation - so while the distributor may "spin up" just fine on the machine, when you put the cap, rotor, wires and plugs in the engine, it may leak voltage to strange places. Due to this, on my distributor machine I have a custom setup to test the engine ignition system --> coil(s), cap, wires and plugs.

This is particularly important on the ole' Harman Collins dual-coils with the yellow mid-plate. Those mid-plates can leak secondary spark/voltage all over the place - the problem is quite typical. The symptom is that 4 cylinders will run fine and 4 will either not run, or have terribly intermittent sparks and dropped cylinders.

Here you can see "Frankenstein's Tester" in action: LOL

https://youtu.be/3xduaVyzx10

10-24-2023, 08:03 PM	#11
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,906	Re: 47 V8 ignition mystery One of the challenges can be that distributor machines don't test anything to do with the secondary side of the equation - so while the distributor may "spin up" just fine on the machine, when you put the cap, rotor, wires and plugs in the engine, it may leak voltage to strange places. Due to this, on my distributor machine I have a custom setup to test the engine ignition system --> coil(s), cap, wires and plugs. This is particularly important on the ole' Harman Collins dual-coils with the yellow mid-plate. Those mid-plates can leak secondary spark/voltage all over the place - the problem is quite typical. The symptom is that 4 cylinders will run fine and 4 will either not run, or have terribly intermittent sparks and dropped cylinders. Here you can see "Frankenstein's Tester" in action: LOL https://youtu.be/3xduaVyzx10