I'm working on my grandpa's '23 roadster. I'm having ignition issues. When I consulted my grandpa on the issues all he had to say about it was he had never messed with them but heard if you touch the wrong part you get a nasty shock. Well, I used the wrong screwdriver when testing for spark at the plugs and still managed to shock myself. I have spark at 1 plug and don't hear much coming from the box. I just cleaned the commutator parts hoping that would fix the problem, it did not.
Could anyone draw me a picture of what exactly not to touch in the coils?
Also what post do I ground to test them? Is this done with the key on bat, mag, or off?
I've been an automotive mechanic for 10 years but am new to the old technology and this is a learning experience. Any help would be greatly appreciated.
Also, I forgot to mention, there isn't a lid for the box, is it required? I thought I saw a different post mentioning the lid held something in place. I could hijack one from another T if that helps.
The only reliable way to check a coil is with a HCCT but if you are just trying to see if you have spark at the plugs then remove all plugs then hook them back up to the wires and lay them on the head turn the switch to BAT then rotate the hand crank slowly you should see the plugs fire 1 2 4 3
If the coils are firmly seated in the coil box the lid is not necessary but desirable
You can test them with the key on Bat. Run a test wire from ground to the top post for each of the coils. This should be where the wire that comes from the commutator is connected. As you probably know, the commutator grounds each of the coils in turn as the rotor turns. As far as what not to touch, that would be the points on top of the coil and the ignition wires, obviously. These come from the lower posts on the coil box. The lower-most single connection post is where power goes in (6V or 12V battery or around 14V on mag.)
Yeah, messing with the coils is a bit of a specialized deal. There are plenty of folks who do their own coil adjustment work, but most T'ers either send theirs to their local coil guru or just get fresh ones from Brent Mize or Ron Patterson.
What is your ignition issue?
You can take coils out of box and make sure all contacts are clean. The lid also helps to press the coils down and hold them in place.
Want to make sure that battery is charged and has a good ground and that all connections on coil box are clean and tight. If that STILL doesn't fix it, you may need your coils rebuilt. Are there any other T'ers in your area? They probably can/will loan you known good coils to help isolate your problem.
You don't need to have the lid on, it holds nothing in place.
Since you don't have a means of adjusting the coils, don't try to adjust them. Although it's not a sure means, you can check the strength of the spark by energizing a coil (either by turning the crank until that coil is energized or by running a jumper from ground to the coil ground) and then use a (well insulated) screwdriver and let it rest on the top of the spark plug with the tip near the head. A good strong spark will jump somewhere between 1/8" and 1/4" with a robust, continuous spark.
There are two pairs of what I'd call "hold-down tabs" on the under side of the coil box cover that hold all four coils down so that electrical contact is maintained, even when driving on rough roads, etc. I am reasonably certain that "Henry" would not have put those tabs there if they were not necessary!
If your coil box is in good shape and you have strong contacts then a lid isn't critical. I've driven a TON without a lid. At the same time if you have a lid on hand it should have some tabs like Harold says and they help squeeze the coils down and help them remain in place.
If you do have a weak coil or suspect a weak coil, they can usually be readjusted with the right equipment and a little knowledge. You can talk to your local T club to see who has the right equipment and can show you how it's done. The 'HCCT' that GR mentioned above is a "Hand Crank Coil Tester' and is the best way to adjust the coils. It's also a very expensive thing that can be hard to come by. Many people are able to make coil adjustments with the less expensive coil testers out there. It's true that there may be flaws in the coil that these less expensive testers will miss, however testers like this have served me well over the years doing 'tune-ups' on working coils. Well tuned coils can make a surprisingly large difference in engine performance, so I try and at least check mine once a year, regardless of how the engine is running.
The coilbox lid holds the coil down in the box so they make good contact and work reliably.
Ron the Coilman
Wow, great quick responses, my main problem is the lack of spark, sometimes it will kick over but I think it is just the one cylinder that does have spark firing off. I'll pull and check the plugs again instead of the screwdriver method. I'm honestly not sure if there are other T people around other than Birdhaven in Colfax, IA, I haven't been doing this very long yet. If there's still no spark I'll test the coils and get back to you guys.
Guess you said it better than I did Ron,.....harold
My car would never run right with the lid in place (it must be touching the tops of the coils) so I never run with it on. It is true that my box is in good shape and the coils fit in the snuggly. Sometimes I have a coil that's a little loose do to some flaw in the wooden case. In these cases I just put cardboard shims in there to hold them tight against the contacts. Besides, to hold the coils against the contacts, they need to be pushed forward, using the lid to squeeze the sides together pushes the coils together, but not forward. The lid is nice to keep moisture and crud off the points, but I'm pretty sure that's in only designed purpose.
If you have one plug that is not sparking, make a note of where your coils are and then swap them around and see if the same plug doesn't spark or if now it's a different plug. That will tell you if the problem is the coil or something else.
I like that idea Seth, I hadn't even thought about that, no electricity, no problem, no new hairdo!
Well, Ron has 1000% more experience with coil boxes than I do, so I'll concede the point.
Try a post titled "Any T guys in ___ County, Iowa?" with the name of your county. That may find you somebody nearby with some experience.
Here's a diagram for your roadster that may help.
And since you're new to T's, here's something else for you: http://dauntlessgeezer.com/DG80.html
In your second post in this thread you said: "Also, I forgot to mention, there isn't a lid for the box, is it required? I thought I saw a different post mentioning the lid held something in place. I could hijack one from another T if that helps."
Does this mean you have a 2nd Model T? If it's running, could you try using the coils out of it to check if that is indeed your problem?
Actually funny story, I have 3 T's to work with, I've already gotten the other 2 running. I hadn't even thought about robbing a whole coil to test, just the lid. Good point.
Steve, I actually have a copy of the black book laid out in front of me along with a wiring diagram very similar to that here as well. What I was worried about is it never tells me what I shouldn't touch.
you say a 23 Roadster. I presume it has a battery and starter (some did come without starter). If so, you can test your coils with the switch on battery. Put the spark lever all the way up and lay your spark plugs on top of the head with the wires still connected. Then switch to batt and turn the hand crank slowly. You should see the spark plugs fire in this order 1243. Whatever plug fires first starts your order, so if #3 should fire first, the order would be 3124. If they all fire, you don't have a problem unless the timing is not set correctly. The only place that will give you a big shock would be the spark plug, and the wire connecting the coil box to the spark plug. That will only give you a shock if the coil is buzzing.
The above post about switching coils with another car which runs well is a good way to check your coils. You can also substitute your coils one at a time in the other T which runs well and see if it misfires with that coil in place.
Yes the lid will keep your coils from bouncing out and it should be on while driving.
Here is a photo of the inside of a 1923 style coilbox cover.
The metal strip inside the cover with the four half moon reliefs that fit around the coil adjuster bolts/springs also hold the coils down (front of car wooden edge of the four coils)inside the box so they make contact with the coilbox to coil contacts.
Ron the Coilman
Well I walked up to the depot hack and hijacked the lid from it, must be a similar year because the inside looks just like the '23 lid above. I'm stopped until tomorrow while my battery recharges. In the mean time I pulled the coil box off the roadster to clean the connections. I tapped the buzzers with a screwdriver to see if maybe they were stuck, I now have two that buzz while turning the engine over.
I do not know if any one say anything about this, but it just may be bad contact between the steel bolts and the brass contacts in the coilbox. I find that all the time. If this car has been setting a long time this is a problem. Dan
The coil hold down feature of the coilbox lid is pretty much the same from 1914-1925.
Ron the Coilman
Use a jumper wire. Clip one end to ground and touch the other end to the each of the four upper terminals of the coil box coming through the firewall. If you get a buzz on all four now, then your problem is with the timer or the wires coming from it.
BTW, it won't shock you to touch the points with the engine running. I hold down the lower point one at a time to kill each cylinder to check how well each is contributing. Kinda like grounding out spark plugs, but can be done while driving. It also amuses people at a car show to hold one down and run on three cylinders, then two, then one, then none, then hope for a free start when you let go of them all.
Good trick Hal.
Got my first free start two days ago and now I'm hooked on them!
Regarding your post immediately above.
Give me a call today when I am in the shop and we can discuss easy ways to get your limping coils going.
Ron the Coilman
To sand the inner contacts do the wood boxes just lift out of the case or is there a trick to it? I would imagine Dan has a good point, I know the car hasn't been driven much if at all since I've been alive.
The best way is to take to box out, remove the contacts and bolts. Blast the heads of the bolts, clean up contacts. Then solder to bolts heads to the contacts. This way you get the best contact between the two. Thanks, Dan
Here is a photo (underside) of the Improved Car 1926/7 coilbox cover showing the coil hold down tabs Harold was referring to.
Ron the Coilman
The individual coils just lift out unless for some reason the wood case has swelled then they can be difficult to remove.
I got them swapped and it runs like a dream (actually better than the one I robbed.)I'll get something done about the 2 bad coils next. Thank you guys for all your help!
Glad it worked out, thanks for posting back to let us know the problem is fixed.