I was doing some more tinkering on the T the other day and I just wasn't happy with how it was running. Lots of shaking, not a lot of power. So, thinking that I had a plug that wasn't firing I shorted them one by one until sure enough, #4 was just along for the ride. Fuel valve closed, let it run itself out, then slowly crank to see if all four coils are buzzing in turn. Confirmed no buzz from #4, swapped it with #3 and the problem followed the coil.
For the time being I've put a plastic case coil in there which is probably way out of adjustment but at least the engine runs. What bugs me is that I bought the bad coil about two years ago from one of the most reputable vendors and it has probably less than an hour of operation on it. It was advertised as coming pre-adjusted on a HCCT and I haven't done anything to it other than install and remove.
Bearing in mind I'm learning T mechanics as I go, is there anything I can do to troubleshoot the faulty coil?
Things happen, even with the best suppliers.
Call the supplier personally, explain the situation, and explore your options with them. My bet is that they will gladly replace the coil with another one for little or no cost to you.
While you're at it, make the situation a win-win for both of you by paying for a spare coil to be shipped out to you along with the discounted replacement.
Tim, I know exactly where you are coming from. Except that, I had a set that was rebuilt and had idle time only for ten years they were in the car while life happened and the car mostly sat. One of them went dead upon me resurrecting the car.
Called the person that did the rebuild (very reputable on here), and upon me sending it back, he discovered a bad (cold) solder joint. He fixed it right up along with three more coils I sent to have rebuilt. I received 4 fresh coils back, for the price of three. Find anyone with that liberal of a warranty.
On the flip side of the coin, you also have to remember these are 100+ year old electronic parts, sometimes poop happens and they will fail and just can't be fixed.
Loosen and tighten the 4 mounting nuts. Sometimes, some corrison can occur if they are ideal, unless they have dielectric grease or something similar on them.
If I am the culprit, and I am at fault simply send the coil back and I will fix it free.
I rebuild 1000 Model T coils every year and try as I might to find all latent faults about 3-4 get by me every year. My invoice for rebuilt Model T ignition coils clearly states "sometimes undetected latent faults can occur and usually happens in the first few months of actual use. If this happens PLEASE DO NOT ATTEMPT TO ADJUST THE COILS AND IMMEDIATELY CONTACT ME SO WE CAN ARRANGE TO CORRECT ANY PROBLEMS".
Upon investigation of these faults it usually turn out to be a 90+ year old solder joint that has decided to fail or as Andy Loso points out, loose point mounting nuts.
If you need my help let me hear from you?
Thanks guys, I'll give the vendor a call on Monday.
Just to be clear, I wasn't accusing anyone of selling an inferior product. I was more fishing for reasons I could have screwed this up myself.
Monday is a holiday, vendor may not answer..... If I am the one who sold those coils, send a 4 back to be checked over and calibrated. Thank you.
Thanks Tim for giving the vendor a break and contacting him. The vendor will appreciate it. Your a class act for not 'naming' anybody before you talk things over with him.
Wish everyone would do that.