While trying to hunt down my carb problem (see engine back in thread) I had my '26 T running and carefully placed my hand slightly above the hot exhaust manifold to see if I could feel any air coming out of the copper seals, I don't think I touched any spark plug wire with my hand but I received one heck of an "ignition system" type shock! woke me right up!!!! I may have brushed the head with the back of my hand, but I am almost positive that I did not come in contact with the top of the spark plug so I was wondering if I could somehow have a short in the system and how i would go about testing to see if there is juice going to the block without using myself as a tester?
Generally it is safe to say that any thing electrical can short out. Or even "leak" through insulation. To locate HV leaks, get a probe with a neon bulb. There are some available for checking spark plugs. Others from electrical supply stores for voltages over 50 volts AC/DC.
Most likely you got a jolt from the spark jumping from one of the wires or plug ends to your hand. You would not necessarily have to touch the wire to get a jolt if you were near the rather large spark plug terminal end. You might also get a jolt from the plug wire if it were cracked near where your hand was or if your plug wire was not really highly insulated plug wire. Some guys like to have fun and use barbed wire for plug wires and it will work so long as the spacing from wire to wire to head is wide. Since the job of the timer is to ground each of the timer wires in turn as the engine rotates it is unlikely to have caused your jolt since none of its wiring is carrying spark plug High Voltage energy.
The timer "shorts out" four times per revolution. Its function is to provide a ground to complete the circuit for each coil's primary winding. When the timer's contacts touch, completing the circuit, current is able to flow through the primary winding. The moving current induces a higher voltage current in the adjoining secondary winding, and that goes to the plugs. So I would say the current that nipped you shows that the timer is working.
One way that the timer can malfunction in the grounding department is for the timing rod to be bent so that it comes in contact with one of the timer's top terminals. This makes one coil buzz continually and will soon ruin the coil. This wasn't happening in your case. Your engine wouldn't have been running.
The only reasons for your shock that occur to me are: 1 You really did touch a plug; 2 You got close enough for current to jump the gap between the plug and your hand; 3 Current leaking from a plug wire.
Now watch. Somebody who really knows electricity will explain why I'm full of baloney.
Thank's for the info guys, I am now inclined to think that I just got too close to my 3rd champion X plug (with the big brass tops), I just wasn't sure because it, well because it "shocked" me to get "shocked" like that, Ha Ha! the thing that made me think of the timer, was that I have been trying to narrow down a rough idle problem and was going to pull the timer off next to see if I could have messed anything up while setting it! After the shock, I was reluctant to touch the head to find out if it was a short!!!!! I now feel betrayed that this T would bite me after I have done all I have done for her!!!!LOL, Thank's again for the info!