Wiring help –getting direct DC power to coils bypassing ignition switch

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
Dave_Kriegel
Posts: 47
Joined: Sun May 05, 2019 8:50 am
First Name: David
Last Name: Kriegel
Location: Indiana
Board Member Since: 1999

Wiring help –getting direct DC power to coils bypassing ignition switch

Post by Dave_Kriegel » Sun May 05, 2019 8:52 am

Wiring help –getting direct DC power to coils bypassing ignition switch

Well men I need help. I am getting a 1918 Ford running again after decades of storage so a grandson can give the running car back to his 94 year old grandfather running. I need to do this quickly this week as the grandfather is ill. It has zero compression, no spark and a rusted carb. I am doing a ring and valve job and new carb - easy. The car has an old coil box with the switch on the coil box – switch appears to be rusted and broken. All suppliers are out of modern ignition switches and ammeters for a substitute. So my question is for a temporary fix to get the car running. How can I wire DC power to the coil box direct from the battery with a simple on and off toggle switch so I can get the car tested and running? I have removed the cover plate for the coil box switch Can I somehow manually connect power here? Looking at diagrams I see on the engine side of the fire wall there are connections for power from the battery and magneto to the coil box but I do not see how this power is interrupted by the ignition magneto battery switch and how I can bypass it? Sorry for being so dumb Ideally on the short term I just want to run power to the coils from the battery with the simple manually on off line switch

User avatar

Jeff5015
Posts: 67
Joined: Sat Jan 12, 2019 3:20 pm
First Name: Jeff
Last Name: Schroeder
Location: Pensacola FL
MTFCA Number: 50300
MTFCI Number: 87
Board Member Since: 2019

Re: Wiring help –getting direct DC power to coils bypassing ignition switch

Post by Jeff5015 » Sun May 05, 2019 9:26 am

Bob Cascisa has made some great diagrams here: https://nebula.wsimg.com/bfee1cac0d0763 ... oworigin=1

They say they are for 1919-1927. They match my '16 because it has a '24 engine.

I don't know if a 1918 is that far off.

Jeff
1916 Touring


George Hand
Posts: 44
Joined: Sun Jan 06, 2019 12:02 pm
First Name: George
Last Name: Hand
Location: Preble NY
MTFCA Number: 28114
MTFCI Number: 21834

Re: Wiring help –getting direct DC power to coils bypassing ignition switch

Post by George Hand » Sun May 05, 2019 9:29 am

On my 1922 Fendered chassis with a cowl I took 3 pole double throw toggle switch and wired battery voltage to one outer terminal, out put from the flywheel magneto to the other outer terminal and a wire from the center terminal to the lower left side of the coil box on the engine side of the firewall taped up the bare wires and taped the switch to the steering column. No other wiring needed if it is a true 1918, if it has a generator you may want to unhook the output wire and tape it off add a short wire to the generator and ground it to prevent damage to the generator. I would probably use a 12v battery as it's voltage will help the coils have better spark. Get-Er-Done you do not have a lot of time, hope you can make someones Gramdpa happy.


George Hand
Posts: 44
Joined: Sun Jan 06, 2019 12:02 pm
First Name: George
Last Name: Hand
Location: Preble NY
MTFCA Number: 28114
MTFCI Number: 21834

Re: Wiring help –getting direct DC power to coils bypassing ignition switch

Post by George Hand » Sun May 05, 2019 9:34 am

In addition after rereading your post, skip the 3 pole switch for now just wire a basic 2 pole single throw switch as you had ask about, it will work


Topic author
Dave_Kriegel
Posts: 47
Joined: Sun May 05, 2019 8:50 am
First Name: David
Last Name: Kriegel
Location: Indiana
Board Member Since: 1999

Re: Wiring help –getting direct DC power to coils bypassing ignition switch

Post by Dave_Kriegel » Sun May 05, 2019 9:42 am

Thank you ALL !!! from the wiring diagram page 5 it appears the blue wire running from the ignition switch to the coil box, I can bypass the non existent ignition switch and wire 12 volts ( suggested) direct to the battery Car has no generator nor starter Wire a on off toggle switch to the steering column for temporary starting ???

User avatar

DanTreace
Posts: 1210
Joined: Sun Jan 06, 2019 10:56 am
First Name: Dan
Last Name: Treace
Location: North Central FL
MTFCA Number: 4838
MTFCI Number: 115
Contact:

Re: Wiring help –getting direct DC power to coils bypassing ignition switch

Post by DanTreace » Sun May 05, 2019 9:47 am

As George posted, to get DC to the 'hot' contact strip at the base of the coil box, remove the 'green' wire in photo from its terminal, and splice new hot wire to the green wire via a toggle switch from a small 12v battery, for battery ignition of the coil box. That way you are by-passing the rusted up switch contacts, be sure to clean the brass contacts in the box so the coils make good contact too.
808806.jpg
The best way is always the simplest. The attics of the world are cluttered up with complicated failures. Henry Ford
Don’t find fault, find a remedy; anybody can complain. Henry Ford


Topic author
Dave_Kriegel
Posts: 47
Joined: Sun May 05, 2019 8:50 am
First Name: David
Last Name: Kriegel
Location: Indiana
Board Member Since: 1999

Re: Wiring help –getting direct DC power to coils bypassing ignition switch

Post by Dave_Kriegel » Sun May 05, 2019 10:26 am

My thank you to all the great replies. I stopped working on 1940-1950 cars 20 years ago when parts became so hard to find and I discovered Model T's They are so easy and fun to work on. I get great pleasure on hearing an engine start again after decades of not running !!!! :D

Post Reply Previous topicNext topic