Coil Adjustment

CatMan1

Senior Member
My car seems to have many issues and I keep plugging away at it. Always working on it more than driving it, but I suppose that’s ‘T Life’. One thing I need to check on is the coils. I bought rebuilt ones 4 years ago and have put less than 20 miles on them. Surely they are still in good shape, right? Do any of you adjust your own coils? I don’t have any special equipment, do you? Is it time to think about a distributor?
 
Simple test remove a spark plug put any wire on it turn over engine with crank till a good spark spears note which coil is working next wire which coil good spark take note same thing with the two others. You are watching for a crisp blue spark if any one shows a weak yellow or no spark thats the bad one. Most likely a bad/weak condenser. and then could be a bad spark plug. I watch'd a guy getting inspection his car a 23 a twin to my 23. while in line he was proud of his new distributor now he is next, car won't start they pushed it in the shop he came out I say watch this I only turned the Ign to battery ITS running so I say one bad coil and I got 3 more to get home LOL
 
I’ve probably spoken on it before so I don’t want to belabor it, but the car (‘26 Runabout) will idle well and be decent in low, but when shifting to high the whole car will buck and shake. I’m thinking it might be some sort of misfire and I wanted to eliminate the coils.
 
J Franklin has a good question. Could be any number of things going on but without more information would be hard to make a good guess. Could be anything from dirty points to fuel related issues. What timer are you using and have you serviced it? Have you check the compression? And yes, you do need the correct tools to adjust the coils. Don't overdo it, but have to checked to see how tight the nuts are that hold the points? They can get loose when the wood dries out and lose connectivity.
 
I’ve probably spoken on it before so I don’t want to belabor it, but the car (‘26 Runabout) will idle well and be decent in low, but when shifting to high the whole car will buck and shake. I’m thinking it might be some sort of misfire and I wanted to eliminate the coils.

That could be fuel related, could be running too lean. Have you tried adjusting the needle valve?
Could also be not getting the timing/speed/fuel going from low to high correct and need more practice. Each car is different. My 25 with wood bands I don't have the bucking like my 1916 that I haven't got its pattern down yet but have only driven it 2 times so far.
 
J Franklin has a good question. Could be any number of things going on but without more information would be hard to make a good guess. Could be anything from dirty points to fuel related issues. What timer are you using and have you serviced it? Have you check the compression? And yes, you do need the correct tools to adjust the coils. Don't overdo it, but have to checked to see how tight the nuts are that hold the points? They can get loose when the wood dries out and lose connectivity.

It has the stock timer and it’s nearly new. I keep forgetting to check it, but it’s barely gotten 20 miles on it, too. I have done a compression check, but I can’t find the results. I’ll have to do that again.
 
That could be fuel related, could be running too lean. Have you tried adjusting the needle valve?
Could also be not getting the timing/speed/fuel going from low to high correct and need more practice. Each car is different. My 25 with wood bands I don't have the bucking like my 1916 that I haven't got its pattern down yet but have only driven it 2 times so far.

It could be driver experience or lack thereof. I understand how to drive it well enough, but I could always be missing something. I know to retard the throttle when shifting. I don’t always think to adjust the GAV when driving it. I know how to get it set for when it’s sitting there idling.
 
We don't refer to the carb. mixture rod as a GAV in the Model T circle - from a slightly closed (not tight !) position, open approx. 1 & 1/2 turns for cold start then lean out as the engine warms up - might end up at 3/4 turn +/-. You should not have to adjust it after it's up to operating temperature.
 
The coills have a narrow range of adjustment and are best adjusted with either an old hand crank tester or modern ecct box. The main thing though, is to do an operational test first. They need buzz consistently and have enough spark to light the fire. If they all buzz and spark consitently then they should work to run the engine.

The carb has to have a working float valve with no leaks. If it idles well then that circuit is good. The mixture adjust has to be within a range that will give decent above idle performance as has been mentioned. Start it in the rich position the lean it back after it's warm. You'll notice it stumbles if leaned back too far. Set it for smooth running after. Once it's set to run then it doesn't need much more unless load or altitude changes a lot during operation. Load requires a bit more fuel and higher altitude requires less.

It takes time to get used to throttle changes between low and high gears but the spark is different. It only has to be retarded to start. Set it to run about half way down after start and then it only requires retard if going up a long hill or pulling a load if it tries to ping.
 
Are you getting up enough speed in low before going into high gear? Are you gently accelerating once in high? this is necessary to make a smooth transition on the road.
 
Are you getting up enough speed in low before going into high gear? Are you gently accelerating once in high? this is necessary to make a smooth transition on the road.

Some of my issues could be driver error. I have heard many ways of doing this. Some have said that I should be able to shift halfway through the intersection. Sone say to wind it up before shifting. I’ve tried both, I believe, but not too successfully. I think I do tend to advance the throttle pretty quickly and maybe that is an issue?
 
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