Stupid Question

[Model T Ron]

I am now working on my 24 Coupe so its not able to be started but this is the first T I have had with the original buzz coil ignition system. When the car was warm I was able to start it on Mag (Simply forgot to switch to battery)......is this normal ? Did not try it cold but would it start on Mag when cold? Once she is buttoned up I was going to try.

[Kerry]

Yes, starting on mag with starter or crank handle hot or cold is what a good mag is supposed to do.

[Craig Leach]

Hi Frank,
Thank you for a straight forward answer to a straight forward question. I salute you.
Craig.

[Model T Ron]

Thanks for the response. From what it looks like the engine has very little use since a rebuilt so the Mag must have been addressed as well. To be honest I was surprised she started on mag as I always thought you needed to start on Battery.

[TXGOAT2]

It is generally agreed that a Model T will run better on magneto than on battery. A car in good condition will start readily on either battery or magneto, using either the starter or the hand crank.

A car with a weak magneto may start more easily on battery.

The magneto's output is dependent on how fast the engine is cranked, so a very cold, stiff engine may start more easily on battery, especially if the magneto is somewhat weak.

[speedytinc]

Early T's were designed to be started on mag. The addition of a "hot shot" battery wasnt necessary.
A good magneto system will easily start on one 1/4 pull. Not many T's today have a good, hot mag output.

[Mark Nunn]

Many people who start on magneto advance the spark lever 3 -4 notches from full retard before cranking. This assumes that the timer rod is adjusted so that spark occurs 15 (or 15.5) degrees after top dead center following accepted timer adjustment procedures. The reasoning is due to the waveform of the magneto output. There is an excellent description of this theory here.

https://www.mtfca.com/encyclo/ignition2.pdf

[Oldav8tor]

Mark is spot on with his suggestion to advance the spark slightly. I start on mag all the time. My understanding is the difference between battery and mag is the battery voltage is constant from the get-go while the mag voltage is dependent upon speed of rotation. If hand cranking you need to bear that in mind if starting on mag. On battery, if you just happen to have the pistons in the right position and the right coil buzzing simply turning the switch on can give you a "free" start (sometimes.)

Note: I have a 12 volt WOSP starter that spins the engine over faster than a standard 6 volt Ford starter. I'm sure that helps when starting on mag.

[JTT3]

Ron, just to add a precaution, if you are going to start on mag by hand cranking, use your left hand, thumb tucked or you could develop T’nis elbow, wrist or other injury. I alway make a habit of looking at the quadrant to make sure the spark lever is retarded to the sweet spot for hand cranking a T on mag. In my youth I used my right hand until Miss Magnolia schooled me. To this day I have pain in the joint of the V between the thumb & index finger
Best John

[Norman Kling]

Mark mentioned advancing the spark 2 or 3 notches. Be careful if you do this. The earlier cars had wider notches than the later ones, and it depends on the condition of the timing rod and the lever at the bottom of the rod whether it has play in it. So if you decide to try this advance, use your left hand and pull up on the crank. when you get to the top, raise your hand immediately so that if it kicks back it will miss your hand and arm. Then when you find the best setting, always do it the same way. If you replace the timer you might need to re-set the retard by bending the rod so it is in the right position.
When I have a working battery, I like to start on battery and then after it starts, switch quickly to mag. It will usually start easier on battery but run better on mag than on battery if your have a good mag.
Norm

[John kuehn]

JTT3 makes a good point. Always be alert and start with your left hand and your thumb not wrapped around the crank handle when hand starting on mag. Advancing the spark slightly would help in starting but remember that Ford started putting a starter on T’s for a reason.

[Steve Jelf]

The main practical difference between starting on MAG and starting on BAT is that on magneto you have to move it fast enough to produce sufficient voltage. When the voltage is coming from the battery, any movement at all will do.
https://www.youtube.com/watch?v=3pv6HWWOGYA