MTFCA Forum

Ok , going to sound dumb here , I’ve just replaced all the wiring in my 26 roadster pickup project, I think my starter is bad as I have made a good clean ground and also ran an addition ground wire from the mounting bolt on the starter directly to the battery . Engine barely tunes and ground is super hot ( brand new battery ) also , a separate issue, my passenger side headlight is very bright and the drivers side is very dim, rotated the plug for the lights 180* and still same issue . Any pointers as to where to go from here . ?? Thank you !!

Replace every single wire on your car. You will be amazed.

Instead of being a parts swapper, try a "voltage drop down test" under load for each wire concerned in those two circuits, instructions and videos galore for that. Specifically, for the starter, crank by hand first to determine the mechanical rotation resistance. Try starting the engine from different positions.

Oldrusty26 wrote: ↑

Sun Nov 23, 2025 12:39 pm

Ok , going to sound dumb here , I’ve just replaced all the wiring in my 26 roadster pickup project, I think my starter is bad as I have made a good clean ground and also ran an addition ground wire from the mounting bolt on the starter directly to the battery . Engine barely tunes and ground is super hot ( brand new battery ) also , a separate issue, my passenger side headlight is very bright and the drivers side is very dim, rotated the plug for the lights 180* and still same issue . Any pointers as to where to go from here . ?? Thank you !!

How difficult is it to turn the engine over by hand?

Same problem here, Travis. I have new correct wires in the starter circuit.

What kind of battery cables are you using? Most cables available today are not suited for use on six volt systems.

The dim headlight is probably due to a poor ground between the headlight mount and the fender bracket or between the bulb socket and the headlight shell or between the fender bracket and the car's frame.

ALL of the cables in the starter circuit must be full gauge and all connections must be clean and tight. (Be careful when working on the starter cable stud nut on the starter. If the stud turns, it will probably damage the connection inside the starter) All connections must be clean and tight, including the coil box connections and the internal coil box contacts.

Be sure your new battery is fully charged. Most new bought batteries are not.

Try this: Turn on your headlights and then step on the starter. If the lights get very dim when you step on the starter, you either have a bad connection somewhere or the battery is not fully charged or you have 12 volt style cables or the starter needs repair. The battery ground must make good contact at the frame and it must be full gauge. Model Ts are negative ground.

You said your ground wire is very hot. Your wire is too small. 6 volt starters can exceed 200 amps. Google Wire sizes vs. amperage.

It sounds more like a cable problem than a starter problem from here.

A hot cable or terminal is a good indication of a bad connection.

Yes on a voltage loss test along the starter circuit. Thru the switch. (Repop??)
Your headlight has a ground problem. The stem mount must be conductive. No rust or paint interference. Same goes for the socket ground connection in the bucket.
Battery ground cable to frame must be excellent thru a large gauge cable/grounding strap. That connection must continue to the starter body mount & your added external ground cable.

speedytinc wrote: ↑

Sun Nov 23, 2025 3:13 pm

No rust or paint interference.

John is right. We disassembled the frame and painted all the parts. After reassembly, I ended up running a separate ground wire to each light. A short trick is to run a long ground wire directly from the battery (-) for testing purposes, to your passenger headlight temporarily, to see if that will resolve the issue.

Two tips that might help. Solder a wire to the headlight bulb socket and then solder it to one of the mounting bracket rivets in the light. That way you bypass any lack of ground between the socket and the headlight bucket. Care when tightening starter leads is recommended. It needs a thinned down wrench to do this properly. At the starter switch and at the starter, the first nut is run up firmly, not maxed out so the components are squashed.Then fit the cables and the second nut. Using the thinned down wrench to hold the first nut in position, firmly tighten the second. This way the original nut/bolt assembly is nut disturbed and the second nut becomes a solid locknut.

Hope this helps.
Allan from down under.

The hot spot is your point of high resistance.

m_p_dean@yahoo.com wrote: ↑

Sun Nov 23, 2025 5:00 pm

The hot spot is your point of high resistance.

Its not clear which ground wire is getting hot. Starter to frame?: indicates a poor ground @ that connection.
Since that extra ground is not necessary & redundant. It indicates the starter, itself is not making the ground connection it should.
Powder coated frame?? Heavily painted or gasketed surfaces??
If the ground cable from battery to frame is hot, its the connection to the frame or a substandard sized cable Or bad connections on/in either/both ends of the cable.

No dumb questions - if you need help, you need help. This forum is a mix of guys who've been in the hobby for 50 years and others that just unloaded their first Model T. Never be afraid to ask a question. If you think you have a common problem, you can always do a search first. I often pose questions on google since google scans this forum and often gives answers from previous postings...even from the forum that preceded this one.

I've attached an article by Ron Patterson that describes a common starter problem. That said, I agree with the other posters that you need to confirm that the wire from battery to starter is big enough {welding wire - 0 awg] - also, the condition of your foot switch can add to the problem.

I've had problems with my light sockets grounding within the headlight assembly. I attached a wire from the internal socket adjuster screw to a screw that i added to the bucket. I drilled a small hole, screwed a sheetmetal screw in from the outside into a tinnerman nut to secure the other end of the wire. It made a much more reliable ground. You can check if that is your problem by removing the headlight bezel and touching a wire from the socket to ground. If it gets brighter, that's probably your problem.

Best of luck!

Thanks for all the responses !! Very much appreciated, the cable from battery to starter switch is original to the vehicle , as Is the ground cable ( braided type ) I cleaned the frame to bare metal and drilled and tapped a 5/16 hole and rebooted the original ground strap to the new location , same issue , didn’t get to the headlight issue as I ran out of time ( started to put together a 25 roadster project my late father never got around to doing too !! Lol ) , I will check these things tomorrow after work . The starter that I put on the 26 roadster pickup was one out of the cabinet in the barn , it could very well be bad , ordered a rebuilt one from langs , it’s on back order . Thanks again !!

Got jumper cables? Clamp ground on battery to starter mounting bolt, and try again.
Same? Then clamp the other cable on batt pos and hit the starter terminal.
You'll find the issue pretty quick.

Oh yes , the cable from the starter switch to the starter is original as well

Braided ground cables are not the best. Too often the solder joint at the battery clamp end is compromised and contact reduced. Heat generated makes the problem worse.

Allan from down under.

Travis have you checked with our very on Jeff Stevenson
For a starter? While you’re at it check out his voltage regulators instead of the cutout on your generator.
Here’s his web page
https://modeltstarters.com/#pop_products

Lighting issue solved !! It was the ground , thanks !! Did the suggested jumper cable test with a fully charged battery and starter turns very slow , so assuming the starter is not working properly

There ya go.

Before you condemn the starter, follow the instructions in the attached link. Measure voltage drop across all components in the starting circuit. If you find a large drop anywhere, you need to fix that first. It could save a lot of money on a new starter.

https://www.mtfca.com/encyclo/Starter.pdf

Oldrusty26 wrote: ↑

Mon Nov 24, 2025 6:37 pm

Lighting issue solved !! It was the ground , thanks !! Did the suggested jumper cable test with a fully charged battery and starter turns very slow , so assuming the starter is not working properly

A jumper cable test isnt necessarily conclusive. Did the starter turn over better, but not fast enough for your taste?
Could be a clue to system voltage loss.
Jumper cables are smaller than the required O cable & long. Both factors in not carrying a full amp load.

It still did not turn over with any kind of enthusiasm, I have a 27 Tudor that starts and runs fine . I will do a voltage check as suggested, thanks !!

If you remove the bendix cover you can turn the starter by hand. It should be easy to turn. If the car has stood for some time, and there is any moisture in the starter, it can lead to a breakdown in the babbit bush in the end cover, and this will cause binding. I have had starters on the shelf which turned freely when shelved, but were very stiff when taken down later. A new bronze bush fixes this.

Allan from down under.

It's a lot of work, but I'll go ahead and throw this option out there. You could swap starters between cars, and see if the problem moves with the starter or stays with the car. However, just disconnecting the wire and motor casting and reattaching them could show improvement.

I thought I would add a picture of the 1926 non electric start switch, not often seen.

sorry didn't come up

Very nice !!

Here's a NOS non-starter switch showing the dimmer resistor - it's going over to the classifieds.

So ,, 6.45v to starter switch , 6.45v across switch disconnected at starter , 3.49v to starter when connected .

Travis,

The voltages needed for diagnosis are with the starter turning (loaded)
6.45V open circuit says the battery is charged to start the tests with.
3.49V on the starter says the voltage at the starter is below specs.

All areas need to be voltage tested while the starter is turning (or trying to turn)
Start with the battery and make sure it is still up to the task.
We are looking for 5V or greater at the starter stud to starter housing when cranking.

See: https://www.mtfca.com/discus/messages/1 ... 244465.pdf

Every wire, switch, connection, and ground is suspect until proven to be good.
Get back to us with voltage readings under load and we can get it solved.
Mike

Oldrusty26 wrote: ↑

Sun Nov 23, 2025 12:39 pm

Ok , going to sound dumb here , I’ve just replaced all the wiring in my 26 roadster pickup project, I think my starter is bad as I have made a good clean ground and also ran an addition ground wire from the mounting bolt on the starter directly to the battery . Engine barely tunes and ground is super hot ( brand new battery ) also , a separate issue, my passenger side headlight is very bright and the drivers side is very dim, rotated the plug for the lights 180* and still same issue . Any pointers as to where to go from here . ?? Thank you !!

Is the floor starter switch original or a repop. Have you checked to see if gets hot?

Floor switch is an original , ive disassembled and cleaned contact points , the low voltage read was while loading the starter

So , found a starter in my barn that turned well by hand , removed starter in car , that starter had a gasket between the starter and the block , installed “ new found “ starter in car without gasket and everything turns fine now . Would the gasket have been the issue ? If so , why do they have gaskets ? Thanks

The bolts supply the ground. Jamb a star washer under the heads. Don' t reuse star washers though.

Your old positive terminal on top might be whacko as well.

The gasket has never been an issue with me. Lack of a gasket will be. It is needed to keep oil in.There are four slotted screws or bolts to make the ground between the starter and the block, so the gasket is not likely insulating the starter from the ground. How does the removed starter turn by hand?

Allan from down under.

Removed starter turns easily by hand

Both the starter & Bendix run in oil - you need the gaskets !