I have my 1926 TuDor back together and have driven it maybe 500 miles since reassembly. It starts on the 1st or 2nd pull. I like to crank it and it runs best on the magneto. I've had the engine apart (fully) maybe 4 times in my ownership of the car. Seems each time it's characteristics are a little different. I also have learned more about the model T each time also.
This time I probably have the initial timing set better than any time in the past. The car starts great and run well. In the past when driving, I have generally always advanced the timing to max after starting the engine and never touch it until I stop the engine. Well.. now I have noticed that when I come to a stop for more than a few seconds, the engine seems to start missing, until I retard the timing to about 1/4 from full retard. So with that in mind, I have begun to change the timing more as I drive and have found that ( or at least it is my perception), that it performs better. I only advance the timing to max when traveling 30mph or more, and when in 1st gear at high rpm. At 25 mph I usually have the timing at about 2/3. I know about the books and diagrams showing where the levers should be under different circumstances, but never really paid that much attention to them. I also have a good feel for the ignition operation on magneto. With the lever fully up it is retarded. At about 1/4 I get the first increase in power, then again at about 1/2 and 3/4. Anyway I was just curious about how others use the spark advance on their cars. Thanks Mike
While I'm stopped for more then a few seconds I retard the spark within a few notches of the fully retarded position. This also helps with the initial starting out, once I get up enough speed to go to high, I bring the gas down to get a smooth shift , then as speed picks up I advance the spark a little past midway along with the gas. I rarely go faster then 35 in my 25 Tudor anyway.
Where is your spark while you are idling? I usually have mine about two notches advanced.
It also depends a little on the linkage, some spark and gas levers have more slop then others, some nearly as much as one 4th of their respective quadrant.
When I run on magneto, the engine runs the same from fully retard to about 1/4 down. There is no change. This is just a characteristic of the magneto operation. If you run on battery there is a difference. I idle at the 1/4 down, which is the 1st step improvement on magneto. I also have some slop in the linkage. Mike
I start the car and immediately pull the spark lever to 9:00. Then switch to MAG. I never touch it again unless I am going over 32 - 35 MPH which would be very unusual for me. The other time you would go full advance is going up a steep hill with the engine wide open in LOW.
If descending a steep hill I fully retard the spark to achieve full engine braking with the throttle closed.
On magneto there is only actually 3 stages;
All the way up is fully retarded. I only use this for starting. Quite often I will crank start my '27 on magneto.
As you pull the lever down the spark advance will suddenly change to what I will call the half advanced position.
I use this position for climbing steep hills in high gear and perhaps for slow speed maneuvering (loading onto a trailer, parking in a garage etc). Often I have been able to pass "faster cars" on hills by utilizing this one feature
As you move it further down it will suddenly change to fully advanced. I use this almost all the time except where I have stated.
These three stages are a function of the "power pulses" that are inherent in the T magneto design
I find 4 actual "nodes" on my magnetos. My cars are a 22 and two 26's. The earlier ones might be different. I put all the way up for starting and about 3/4 down for around town driving. When I pull a hill and the engine slows down I go to about 1/4 down and if I go very fast on the open road I pull all the way down. As you drive the car, you will notice how it runs. If it starts to buck or ping or knock, your timing is too advanced for the situation. Push it up to the next "node". When you are not pulling hard and are going fast try advancing it. If it runs faster and smoother, leave it there.
You will also find that with different cars or different timers it is a little different. Same goes for the carburetor adjustment, so experiment with your car and you will find the best position for your particular circumstances.
On my '27 I have a "Best" brand brush type timer. It is probably close to 40 years old. I have "trued " the surface once or twice. The original carbon brush is still in good service. My best guess is 20,000 miles. Perhaps it is a design feature of this timer that I basically only get 3 positions. Living at 3,000-4,000 ft elevation may explain why it never "pings"
I went back and re-read Ron and Steve's 2003 article on ignitions. They say there that there are 4, but depending on the ability or the lever to reach the last one, there may only be three. My car as it sits today seems to have 4 nodes, yet the difference between the last two are minor. There is a significant rpm change on the transition from fully retard to the 1st and a little less on the 2nd. I agree there are many differences between how each car is set up. That is initial timing and linkage slop. I like Norm's statement 'notice how it runs'. Mike
More often than i move the throttle probably.
As much as is necessary for the speed, RPM and load. You are the centrifugal/vacuum advance.
I guess I'm the exception. I never move it. My Grandfather owned it before me and he said he never moved it. Car usually starts on the first crank. It hasn't been driven more than 10 miles in a day for probably 30 years. We have had it since 1971.
I get 4 positions on mine when running on mag. I keep it at the fully advanced one most of the time I am driving it. On the Touring, if find it necessary to retard it one node when shifting into high. On the TT, it's not necessary. It might make some slight difference, but with the low gearing, it has no trouble accelerating even with the spark fully advanced. On a hill, I sometimes retard one node to help get a little more torque. Again, a lot more noticeable on the Touring car than the TT. Of the other two nodes, I use the second one for starting on mag and the first one for impressing people with the low idle speed. Oh, and while it isn't really a 'node' when on battery that first 'node' or fully retarded position is for cranking on battery.
About what Mark says. However the mere mention of centrifugal/vacuum advance means he (and myself) understand how they work. Most don't.
e-timer solves the advance issue
Zero; I start the car on battery and advance the spark lever to near full advance and don't touch it again. That's because I am presently running an Electronic-Timer which automatically adjusts ignition timing based on engine speed. The Automatic Timing Advance feature also makes it much more difficult to stall the engine. Never have to clean, maintain or adjust anything else with the ignition system either.
Occasionally I switch back to a stock timer to enjoy a more authentic Model T driving experience as described here by others but make sure ALL coils are properly adjusted or the car will run poorly regardless of spark lever position. I adjust my coils by measuring the time needed to fire spark and set all 4 coils for the exact same dwell time to fire which minimizes cylinder to cylinder timing variation and helps ensure optimal engine performance.
Model T Electronic Timer
The Tiptop Timers E-Timer is
You guys with the magic Kossor timer are the exception. Mike
How do you go about measuring the time needed to fire the spark? I adjust them to fire at 1.3 amps but the time would depend on how quickly the voltage rises when the coil fires at 1.3 amp. The timing is so quick that you must need some special tool to measure the time between coils firing.
Norman, there are two ways that I am aware of to precisely measure the time needed to fire spark. You can instrument a coil to measure the coil current and display that current with respect to time using and oscilloscope. Then connect the coil primary winding to a 12V battery like the timer does and measure how long it takes the coil to produce the first spark from rest. The easier way is to use an ECCT which does that instrumentation and makes the time to fire measurement automatically. Here is a link to an article which describes both methods in more detail along with photos illustrating what the coil current looks like with respect to time:
Two positions; starting (up) and running (half down).
Guess I should have seen that coming.
Hey, you gotta love it. Some guys love the fancy stuff and some don't. I like fancy, but can only afford plain, but it works for me. Mike
Like Chris, I do: up to start and down (somewhere) to run. The "down (somewhere)" is where ever the "sweet spot" is. The sweet spot is in a little different spot on all of my T's. Because the timer may move a bit when the motor is running, I might twiddle a little to find the "sweet spot" when going down the road, but in general it is the same setting for hills, flat, whatever.
This is with the original magneto, timer and coil set up.
My '19 Touring with roller timer likes 1/3 down and that's it.
Sometimes, depending on how fast (slow) I shift into high I need to retard the spark some until it picks up speed.
My '27 Tudor with Anderson timer likes wide open on magneto but that, of course, depends on how it's set for running on battery.
I rarely fiddle with the spark on the Tudor at all no matter what speed.
There are really only two spark positions that I use on both my coupe and touring. Fully retarded for starting and little past half way down for running. I advance the spark one node more on my coupe if I get up to 40 but, I very rarely do that unless I'm running at a big hill.
The magneto only permits you to make two or three rough adjustments, the e-timer is continually fine tuning the spark advancement. The results are clearly noticeable. Anyone who has one disagree?
I have been in the instrumentation game for 46 years and still wish I had Mike Kossor's knowledge base...the question was asked and the answer given!
I set it and forget it.
I am running a set of electronically fired coils that utilizes a standard style of timer (not Mike Kossor's set-up). I have a full range of advance or retard depending on my position of the spark lever without and nodes to contend with. I leave the spark at the mid-range position for starting out and once the speed warrants it, I advance it to within a few notches of its travel as that seems to be the best spot for high speed. When I encounter steep hills and I'm too lazy to shift into Ruckstell high, I just retard the timing from its advanced position until I'm over the hump, rpm picks up, and I can advance the spark safely.
Once started, I advance the timing lever to just after where the engine picks up speed, and use that setting for suburban driving. On the freeway at 75km/h, I'll run it with the lever all the way down. For hills in top gear, then I'll back it off to get better low end torque. I'll also back it off when changing into top gear if it feels like it needs more power until it picks up speed again. So, yes the timing lever gets a lot of use.
The coils operate from the 6V electrical system, no magneto, and coils are set for equal firing time. Timers have been Anderson, TW, and now an E-Timer (coil points not bridged). I run the E-Timer in manual adjustment mode because I find it unnatural driving a model T without a timing adjustment. Having said that, its automatic timing function does work extremely well - in fact better than I can adjust it manually.
Either way, I find the same method of using the timing lever works for all timers I've used.
Kevin could you give us some more information about, " electronically fired coils".
Creston, sent you a PM.
I have four generators. When I attach the battery positive cable to the positive post on the generator,all is fine. When I attach the ground cable to the generator housing I get a spark. Is the spark telling me there is a short in the generator?