MTFCA Forum

I have a Texas T distributor on my speedster. When I turn it off the spark is advanced.

To turn it on I turn on the coil, give it about half throttle, retard the spark, and push the foot start switch.

Twice now when I retarded the spark she started. The first time I thought I must have stepped on the foot switch without realizing it. This second time I know I did not hit the foot switch.

I guess when I moved the spark lever from advance to retard the points opened and she fired?

Has anyone else had this happen?

The factory distributor equipped ’29 Model A I once owned would on occasion give a free start.

Hang on a second...........if the engine isn't rotating, the points aren't opening. How does that produce a spark and a "free start"?

George Andreasen wrote: ↑

Fri Feb 08, 2019 9:11 pm

Hang on a second...........if the engine isn't rotating, the points aren't opening. How does that produce a spark and a "free start"?

Yeah! But I think that when I move the lever from advance to retard the points open. So if I turn the ignition on, then move the lever from advance to retard, the points open and a plug fires. Does that make sense? It has happened twice!

yup the points are closed with spark advanced--when you turn engine off it will rotate a time or two, depending where throttle is set, this will emit a charge of gas to enter one or more cylinders, now things are all set for a free start, when the spark is retarded at a certain point if the ignition is on, the points will separate, causing the[ in this case where no buzz coils in play ] the charge in the condenser to fire a plug.things need to be in very good condition for this to take place with that type system,

Meant to add, personal , feelings here, model t engines have a high rate of broken crank shafts, this is my feeling on this matter, those [free starts] may not be as free a one would think. in order to understand what takes place in a free start, one piston is called on to set in motion the inter workings connected to the crank shaft at ONE point, 3 other pistons rods cam shaft, fly wheel transmission and every thing connected to it, all has to be set in motion by this one poor cylinder,-- normal starting with crank or starter that sets in motion all this mass as a unit,in other words every thing is rotating, the cylinders take over one after the other as designed, I know of no way to avoid a free start from taking place, think about it--- that's my over 65 years of engine building talking. others will have there feeling on this subject, that's mine and I'm sticking to it. GREG.

George--when the spark lever is moved from advance to retard, the points are already open, and the condenser is not charged ,the points need to close to charge things this takes place when the spark is retarded.the points open when the lever is advanced. causing ignition.

Well Richard Greg, I would say you are right on the money on this. Many years ago, I found out about this. I did it a few times, saw and/or knew people that liked to do that on a regular basis. I have always had a feeling that it could cause damage and lead to future mechanical problems.
I started the 1929 Reo coupe I had fifty years ago that way a few times, and the 1925 Studebaker a couple times. Part of the trick to it is just as you turn the ignition off, open the throttle. Let the last few turns suck in unburned fuel-air mixture to await a spark. I have seen that charge still fire even the following morning (which really surprised me!). When you turn on the ignition, move the spark timing lever, advance, retard, maybe advance again. Sometimes, it takes a second with the points closed to recharge the capacitor. Even if it doesn't fire the first twist, sometimes it will on the second or third. Some cars will rarely if ever stop in a position to fire and free start (especially four cylinder cars which is why sixes are often better).That is just the way it is. Beyond that, all cars are slightly different. Where the motor usually stops turning. And, some cars have points that will not close and open (both are necessary for this to work) in their stopping zone (careful adjustment of the points might be able to fix that).

If you prefer to not free start for the reasons mentioned? First rule? Slow the engine to its lowest idle for a few seconds before shutting off the ignition. That way, hopefully, there won't be enough fuel/air in the cylinder to fire when you turn it back on.

Richard G wrote: ↑

Fri Feb 08, 2019 11:49 pm

George--when the spark lever is moved from advance to retard, the points are already open, and the condenser is not charged ,the points need to close to charge things this takes place when the spark is retarded.the points open when the lever is advanced. causing ignition.

I know this is very simple and should not be confusing me, but... When I turn the car off the spark lever is in the advanced position, about halfway down. When I start it the spark lever has been left in that position. I use no choke. I turn the ignition on which pouts power to the coil. I move the spark lever up to retard the spark before stepping on the start button. When I move the lever up, before I push the start button, bam, she fires up! But, how is that possible since the coil does not discharge until the points open ? Aren't I actually closing the points by moving the lever up?

He's getting a spark. Has to be in order for a freebee to occur so when he moves the spark lever he completes a "cycle" within the dist. resulting in a spark. Not rocket science.

Tom Hicks wrote: ↑

Sat Feb 09, 2019 5:38 am

I know this is very simple and should not be confusing me, but... When I turn the car off the spark lever is in the advanced position, about halfway down. When I start it the spark lever has been left in that position. I use no choke. I turn the ignition on which pouts power to the coil. I move the spark lever up to retard the spark before stepping on the start button. When I move the lever up, before I push the start button, bam, she fires up! But, how is that possible since the coil does not discharge until the points open ? Aren't I actually closing the points by moving the lever up?

Just pop the distributor cap off and look at the points. With the ignition off, retard the timing and see if the points open.

Just pop the distributor cap off and look at the points. With the ignition off, retard the timing and see if the points open.
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Yes, but. This does not occur every time. I have only had it happen twice. So, the distributor has to be in exactly the right position when the engine stops turning. What are the odds the engine will be in that position when I pop the cap off?

Odds are pretty good. As wear on the starter ring gear can testify, engines usually stop in same place. What maybe not happening consistently is enough fuel mix in the cylinder and a sufficient spark.

Free starts are rare with a distributor but more likely with the stock ignition system because of the multiple sparks and the wider crank angle that the spark can occur.

Sorry, but I disagree that free starts can hurt the crankshaft. It is not much difference than cranking it over by hand.

Some early cars, like Overland, had an a starting system where acetylene was sucked into the cylinders by cranking the engine by hand and then the ignition was turned on. Acetylene is very explosive and doesn't have to have an exact air/fuel ratio to ignite.

Richard G wrote: ↑

Fri Feb 08, 2019 11:49 pm

George--when the spark lever is moved from advance to retard, the points are already open, and the condenser is not charged ,the points need to close to charge things this takes place when the spark is retarded.the points open when the lever is advanced. causing ignition.

Whoops...........I didn't think that question all the way through! Since opening the points HAS to occur, there HAS to be some rotation......of something. I completely ignored moving the spark lever so yes, it would fire. Thank you for giving me a bit of a prod!

I have had free starts backwards when I forgot to retard the spark and just touched the crank handle and it fired backwards for 3 or 4 revs, now that puts some stress on the crank.

What the timing rod "rotates" is the plate where the points are attached.

Since the duration of the burning of the optimal fuel mixture has a fixed length of time - if you want any engine performance at all - the spark timing must be readily adjustable to begin the fuel burning earlier or later depending on engine load and rpm. Under heavy acceleration you want less advance which provides a richer mixture and more power. At cruising speed you want more advance to provide a leaner mixture to use less fuel. Why they don't just put in weights and a vacuum can in these "things" is beyond me.