I need to put in a word for those of us who have six volt systems. As many of you know I'm sold on Henrys original system, and this sort of proves it, at least to me. I just fired up my '25 after sitting for seven months. It has a Interstate battery (6volt). The car has all new wiring custom made for me by YnZ's to Ford specifications, and a John Regan coil box back, with Ron Patterson coils. I primed the engine 3 times with the key off, and the choke out, with the spark advanced. I turned on the key and retarded the spark, and it fired up on compression. Doesn't get any better than that!
When I posted this video on Facebook, I was accused of talking about the subject too much, and beating a dead horse.
Correct me if I'm wrong, but I believe the coils don't care if it's 6V or 12V anyway, they just need to be "in tune" for proper performance, right? So might as well stick with the stock system.
Coils on 6 volt will not perform as well as on magneto or 12 volts. Mag and 12 volt operation will be similar to each other. Coils on 6 volt essentially 'retard' the timing and the engine cannot achieve the same level of performance as mag or 12 volt.
Go 12 volts if you have no working magneto and no starter but if you run on mag and have a starter there is no doubt in my mind that 6 volts is all you need. I can't understand how anyone could say that they need 12 volts for starting as I was able to start a Chrysler Hemi in below zero temperatures with a 6 volt battery when I was in school in Syracuse NY.
Each car is different. If your crank starting it probably makes no difference 6v or 12v.
If I had purchased my speedster first I would might have the same narrow minded view. Here is why, I have one of each.
My first T was a 27 Coupe that came with a 12v battery in it and started great.
I purchased a new quality 6v Battery and it was absolutely useless, hardly wound it over and sometimes wouldn't. I tried all the advice, leads etc.
The Coupe (vaporizer) is also difficult to crank start except when its hot for the first few minutes, and virtually never free starts. Its impossible to start on 6v but on 12v it winds quick and starts fast every time, hot/warm or cold!
Yeah yeah I carry a bendix spring, never broken one yet and the previous owner didn't in the 6yrs he had it.
The Speedster (NH) is a completely different beast. It has the same 6v battery I tried in the Coupe and is usually a brilliant starter no matter the method. It free starts, when warm crank starts first try and when cold starts fine. I notice I only have to slowly turn the crank similar to Steve's video above and it starts hence the slower crank of 6v is more than enough to fire it up.
Obviously I have an issue I haven't nailed down yet on the Coupe which requires a faster wind to start it up. Coupe is much higher compression, 88psi compared to speedsters 55psi.
So basically what I'm saying is perhaps other people which run 12v have similar issues and 12v has addressed it and got them on the road, if that's all it takes to give an owner reliable starting resulting in another T driving about I'm all for it.
You guys that are running on 6 volts need to know you are using half of a 12 volt battery.
Ted, you are only running on 6 volts if you fail to turn the switch over to mag! Another advantage to a six volt system, it doesn't slam the poor bendix gear into the flywheel.
Anybody use an 8 volt??? I use them in three of my "T"s. Don
A few weeks back there was a thread about Starter Voltage and Hap posted a great link to an article by Uncle Milt.
In the article it described the best methods to having a properly working 6 volt system, including the addition of an extra ground cable from the frame to one of the starter bolts. Well i decided to try this out for myself, and the results in my opinion are great. I started off by ditching the stock braided ground cable and replaced it with a short length of 2/0 cable, and installed a 1/0 cable from the frame to the starter.
Not sure what the exact percentage improvement is, but i could absolutely see and feel a noticeable difference in the way it cranked and started...Like usual, just my 2 cents.
Here's the T starting after the cable additions.
6 volts works just fine with coils - provided the ignition system is set up the right way. All the complaints I've heard about 6V being a poor performer have been from the U.S, but yet never heard anything bad locally (Australia). To cut a long story short, it seems the initial timing of 15 degrees BTDC used on many U.S cars is the reason for the poor performance.
There is no timing gauge tool for RHD cars(that I know of) so everyone here sets their timing to just after TDC, giving about an extra 13 degrees of advance. This appears to make up for the extra millisecond of retard when coils operate on 6V.
For all of my Model T owning life, I have routinely achieved 75km/h on 6V. At times I can get it even faster, but the thought of something breaking reminds me to reduce the speed.
Part of the trouble with running on six volts may be due to the timing being slightly retarded, but the main problem in my opinion is timing disparity between the cylinders. This is caused from two sources. First is the timer. Now, assuming that your timer is nearly perfect, the other problem is mismatched coils - that is, coils that have different ramp to fire times.
For 12 volts, the timing disparity due to mismatched coils will be half that of coils operating on 6 volts. So, say your coils are off 10 degrees from one cylinder to another on 12 volts. You may not even notice this, but on 6 volts the timing disparity would be 20 degrees, which would likely be quite noticeable. This is not an extreme example. Coils set by the average current method, such as a HCCT are often off by as much as one millisecond from one another in their ramp to fire times. One millisecond may not seem like a lot, but it is 12 degrees at 2000 rpm (approx 50 mph).
In the Montana 500 most of the top cars set their coils by the "ramp to fire" method, rather than the average current method, so when running on battery there is little timing variation between the cylinders. Also, most of the top drivers use Anderson style timers, which can be adjusted to have nearly perfect timing. As such these cars run nearly as well on battery (6 volt) as on magneto.
As an example, here is a story from the 2011 Montana 500 involving Mike Stormo. Mike's wife was one of the time keepers, so at the end of each leg, Mike would reach over and say "hi" to his wife by flashing his headlights. On the leg from Valier to Conrad, when he reached over to flash his lights at his wife, he noticed that he had neglected to flip his key over to "mag" and had accidentally run the entire leg (41 miles) on battery. Even so, he averaged over 55 mph on this leg.
Great thread, lots of interesting info.
I use a 12 volt battery because the LED stop lights use 12 volts and it can power my cell phone and GPS.
I prefer to run on the mag but had a problem with the previous motor so I ran it on the 12 v battery.
I don't know about the size of the cables except we purchased a set of cheep jumpers cables and put the correct connectors on them.
That's ok Larry and Steve. WE still love you.
Tom, indeed I do have my coils set for equal firing time. I should have pointed that out in my previous post as being one of the important adjustments for good 6V operation. Aside from that, I have found the timer condition to also make a huge difference. Until recently, I have used Andersons because of less contact bounce compared to the original roller type. The mechanical reliability is excellent, but the catch is the timing variation as it wears, so I need to work out a way to easily readjust the contacts throughout the life of the timer.
Here the pic shows typical 6V operation with an Anderson timer. That's km/h BTW.
JohnH, I have a big degree wheel that I stick over my hand crank. I advance the spark and short out all four coils so the motor won't kick back. I then put a pointer onto the crank and check to see when the coils buzz. It is a simple matter to adjust the timer and the adjustment seems to last a long time.
Don Kirtley - I use an 8-volt on one of mine. Finding a charger for it was a complete pain.
I agree Ron, I have 2 T's on 8volt, 1 on 6v and another on 12v. for many years I've charged at times a 8 volt with a 12 volt charger on low amps, one battery is now over 7 years old and still working fine.
I picked up at a yard sale not long ago, a charger that self adjusts to plate voltage and you just monitor the amps.
Tom, Your experience with HCCT ramp time to fire (aka dwell time to fire) variation is consistent with data I've taken on HCCT adjusted coils done by an experienced professional and the reason I too prefer that method of coil adjustment.
That's a great story about Mike Stormo running on 6V battery averaging 55mph; The Anderson timer is the only timer where cylinder to cylinder timing can be easily adjusted to my knowledge. Do you have written instructions for doing so? Imagine it is a bit time consuming trial and error process requiring removal of the timer each time a prong is adjusted.
Frank - that charger was a nice find, would love to come across one like that. I have a 6/12 charger - 40 years old and works great. Had to search for an 8-volt online and finally found one.
All my others are on 6-volt, but my '27 T/IHC needs a greater kick to spin her over (a function of how the mowing system was mated with the driveline). Didn't really want to hit it with a 12-volt, so I went with an 8-volt.
I agree that the six volt starting system works just fine on Model T. Steve's video is spot on except I don't have to choke my 4-ball Kingston.
Also, I have watched/helped a friend change his broken Bendix spring on the same car on at least three different tours. I honestly believe just one of those parking lot "training sessions" could get a fellow's mind right about a 12 volt starting system.
If you have cured a "starting" problem with the 12 volt battery, you probably can't hand crank the car either. That is not what I would call handy.
I'd rather have Royce catch me with a water pump on my T's than use a 12 volt starter system. <grin>
Royce - Is Popeye coming to Uvalde? That is one neat set of eyes.
Ken in Texas