i have a miss now as the engine warms up it gets worse,checked the plugs see pic they look ok but really black ,timer is clean just looked at coils see pic they are plastic!!,i can pull the advance lever all the way down it helps some but i am losing a lot of power,looks to me the plugs are not firing hot enough,,if the battery is low(still starts great) could there not be enough voltage to fire the plugs good and still start good?? the round about quarter size disc are free and clean on the coils,help wanna go cruisin''
If your plastic coils DO NOT have yellow stickers on the case near the three terminals they can be made to work properly. I have rebuilt many of them and the guys on the Gulf Coast love them because they do not swell up due to humidity like the wood cased coils making them hard to get out of the coilbox. The plastic coils with the yellow stickers on the box were made for a different application and are not appropriate for the Model T running on magneto.
In my view you have two good options. 1.)Find four (or five) original Ford coils and get them rebuilt. 2.) Buy four newly made coils, BUT be very careful, there are three newly made coils being sold and two of them are poor quality. If you take this route buy the new coil made by FunProjects who have a reputation for making quality Model T reproduction parts. Both will last for 7-10K miles and then need new points/adjustment.
Ron the Coilman
Try separating the wires. Timer wires are ground wires and they should not be that close to the spark plug wires. When operating the engine at night (in the dark), open the hood and see if there is some unwanted arcing.
Ron, the yellow sticker thing is true on the older version plastic coils but the new KW ones being made by Bob Branson are being made differently and have the improved points sets.
He is also potting them differently but he's putting the yellow labels on them and shooting himself in the foot I think......
i can see the yellow stickers from here.
What kind of timer do you have? I have one car with a New Day timer and the brush was completely worn out so that it would not move out far enough to make contact with the cover. When the engine was cold it would run fine but as soon as it warmed up it would start missing. I messed with the coils, even put the new plastic replacement for the wood in the coil box. I replaced spark plugs. I took out the coils from another T which runs fine, and put these coils in the other T. It ran fine, but this one had the same problem with the other coils. I even swapped carburetors, none of those attempts fixed the problem. Each time, the engine would cool down between times, and so I thought I had found the problem. Finally I replaced the timer brush, and the problem was solved.
The problem could be as simple as that. One thing I would suggest before you buy new coils is to try yours in another car and see if it has the same trouble, then try a known set of good coils in your car and see if that fixes the problem.
If your having a problem with a bad Miss
make sure she doesn't become your Mrs.
what is the thing with the yellow stickers?
Ronnie, there are some older plastic cased coils that have those stickers on them.......and it seems a lot of those are junk. They were of lighter weight and, quite simply, inferior.
Inferior enough to give plastic coils a bad name to some.
It is Bob Branson who is making the new, top quality, KW points sets as well as the new KW plastic coils.
Wait till you see the fat man steering wheel hub he's making too!
Fred, a "bad Miss" goes everywhere but a "good Miss" goes to heaven
Borrow somebody elses coils. I chased a miss for quite a while. My coils tested good on two different HCCT, so I rebuilt the coilbox with new contacts and plastic liner kit, and also rebuilt the carb. Still ran bad/missed and got worse as it warmed up. Tested coils again on a Strobospark. They tested OK, although the capacitors were weak, still all 4 were basically equal. Still missed. Finally I borrowed coils from a good running car. What a difference! One by one, I put my coils back in until I found one that always made a miss no matter what combo of other (borrowed or mine) coils it was with. Then I tested the borrowed coils on the Strobospark. Their capacitors were just as bad as mine. Eight coils, all tested similar, yet one caused a miss.
Make sure the rain gutter on the coil box cover isnt grounding the timer connectors. They should be turned 90 degrees and pointed down. Try running without the cover. troop
no yellow stickers on the coils and points are KW,went to start it just now, would barly turn over, battery is way low, will a 6 volt battery have enough voltage to start ,but not enough to operate the coils as it warms up? just noticed yesterday that when running my amp gauge is showing discharge.???back to the shop for a while nice here in tx about 72 ahhh!!!
big opps yes they have yellow stickers on the side,did not see them ,,thought you'all meant on top, does that mean get new coils??,
in the pic you provide you can just barely see the yellow stickers sticking up out of the coil box.
having a low battery could make the engine misfire.
I have found that anything under 5 volts will cause a miss. It is easy to trace a miss by pulling individual coils out while the engine is running, and then switch two to see if the same coil or the same cylinder is the problem.
can you get a 6 volt battery down to 5 volts without the battery being completely dead?
my car has a distributor, and when the generator isnt working, it has a misfire....
That's a nice coat of soot/carbon on that plug. After you get the coil business straightened out play around a bit with your carb jet setting. Before I learned I carboned up a set of plugs so badly the car wouldn't start.
interestingly his insulator appears white, the black deposits on the outside of teh plug look kinda like oil.
Ive got one of those plastic coils on the shelf, and that yellow tag says "positive" which is the timer (ground) and the bottom one says "ground" which is the positive feed from the switch. troop
Yes, you can get a battery below the rated voltage with out it being dead, it will not turn a starter, but even as low as 4.6 volts a six volt battery will make my T run, but very roughly, although after I got my coils tuned, it may run better at lower voltage.
Have you found your problem yet?
Are you using a Fun Projects coil box kit?
You can get a full charged 6 volt battery down to 5 volts easy with the right resistance. And if you've got a potentiometer you can get just about anything you want under 6 volts. :-)
last nite was charging battery my smart charger said internal short!! my be part of problem.as to the mixture,if i try to lean it at all it really gets bad, think i'll pull the carb and clean it really good also