Mag voltage while cranking

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Modeltmike
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Joined: Sat Mar 09, 2019 5:12 am
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* REQUIRED* Type and Year of Model Ts owned: I have 26 & 24 coupe, 25 pickup, and 26 Fordson.
Location: Kansas
MTFCA Number: 31639
MTFCI Number: 31639

Mag voltage while cranking

Post by Modeltmike » Sat May 11, 2019 10:36 pm

What voltage should you get with an analog A/C voltmeter at the mag pickup point when cranking? I’m looking at a non running car that has sat for years and wondering if mag is functional. There maybe other simple test, and open for ideas. Thanks


Scott_Conger
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Re: Mag voltage while cranking

Post by Scott_Conger » Sat May 11, 2019 11:15 pm

A couple of volts

pull 4 plugs out, have someone place leads and a 6V bulb across mag post and ground and have them watch. Spin the engine and the bulb should flicker/flash, though not very brightly.

if it has been sitting for a long time, you might wish to jack up the drivers side rear wheel, place handbrake lever in "neutral" and have a go at it. This will be the least resistance to cranking that you will be able to achieve and thus the highest mag speed.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured

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ABoer
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Re: Mag voltage while cranking

Post by ABoer » Sun May 12, 2019 3:48 am

Mike ; As soon as I mounted the Coilring and Flywheel , I test the mag output . When I crank as fast as I can, then I have about 3 1/2 V AC .
Toon
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User avatar

ABoer
Posts: 203
Joined: Mon Jan 07, 2019 2:41 pm
First Name: Anthonie
Last Name: Boer
* REQUIRED* Type and Year of Model Ts owned: 1912 touring 1923 roadster 1925 pickup
Location: Klaaswaal NL
MTFCA Number: 19790

Re: Mag voltage while cranking

Post by ABoer » Sun May 12, 2019 3:56 am

Scott ; Why jack up the drivers side rear wheel , and not the passenger side ????

Toon


Scott_Conger
Posts: 6428
Joined: Sun Jan 06, 2019 11:18 am
First Name: Scott
Last Name: Conger
* REQUIRED* Type and Year of Model Ts owned: '13, '15, '19, '23
Location: Clark, WY
Board Member Since: 2005

Re: Mag voltage while cranking

Post by Scott_Conger » Sun May 12, 2019 7:52 am

Anthony

either, or both wheels works
I suppose if you do both, you take the differential out of the equation
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured


Topic author
Modeltmike
Posts: 164
Joined: Sat Mar 09, 2019 5:12 am
First Name: Mike
Last Name: Sleep
* REQUIRED* Type and Year of Model Ts owned: I have 26 & 24 coupe, 25 pickup, and 26 Fordson.
Location: Kansas
MTFCA Number: 31639
MTFCI Number: 31639

Re: Mag voltage while cranking

Post by Modeltmike » Sun May 12, 2019 1:02 pm

Just checked. Looks like just over 2 volts with hand crank. May not be a good mag, but likely is a functioning mag. Thanks

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