Went to the HCCA tour in Wallace this last weekend and had a blast! While there, someone was impressed with how quick my yellow speedster was and asked if I was running a "Front Plate Magneto". Being relatively new (about a year) to this affliction I had never heard of such a thing. So I spent some time googling and the picture above is one that I found!
I get how it works in theory - the cam shaft drives the gears which drive the magneto which has essentially a distributor on the back. This one is the correct setup for my '14 engine since I have no provision on the block for a generator. Apparently Bosch made 3 models for both generator and non-generator cars, as well as a chain driven model that could be used on either.
#1 How do you turn it on and off? From what little I can see, it looks like everything for your ignition system is self contained there, so if the car is running and this system by-passes the normal magneto/coils/switch box, do you just have to starve the car of fuel to kill the engine? The top four studs you see are supposed to have wires that go to the spark plugs, then the black one on the bottom - what do you hook up there?
#2 Is this device more accurate or better than the normal coil setup? IE, can it turn more RPM than the normal coils and Anderson timer? I know that's a bit of a heretical question but my car is slowly evolving into a serious go fast speedster. Right now I can zip up to over 50 MPH no problem, but I definitely hit a point where the engine just doesn't want to do more - I'm pretty sure that it'd do plenty more with a Montana 500 flapper spring, but I've also heard that with the buzz coils there's a mathematical limit as to what they make the engine capable of due to the rate at which they vibrate. I don't remember where, but I think I read an article that one of the clubs put together that shows where after something like 2,200 RPM (I don't know exactly how much, it's around there) your spark is hit and miss due to the coils, regardless of what the timer is doing. It may not matter since I'll be bringing the RPMs back down with the Warford overdrive I'm going to install.
Anyway! If anyone can shed some light on this mysterious item I'd appreciate it. If it's a good speed upgrade, and period correct (Like my Warford transmission and soon to order AC brakes will be) then I'll see if I can talk the fella of out it. It definitely looks wicked cool on the side of the engine. Thanks!
A high tension magneto works differently than Ford's low tension magneto. The main advantage is better spark accuracy at high speeds, so it makes sense to use a high tension magneto on a period speedster.
There has been discussion about the type of magneto drive you show above - I think it may need a special timing cover to make it fit? That's often a reason for them being offered for sale..
See this thread: http://www.mtfca.com/discus/messages/257047/270216.html?1330220794
In fact it isn't necessary to find a scarce & expensive old magneto drive - you just have to find a good high tension magneto & can make a magneto shelf for the LH side of the engine out of some angle iron + a couple of chain sprockets.
Bosch also marketed that simple style of mag drive in Sweden back in the 20's:
Back to your questions:
1. A ground wire for the breaker points can be attached to a high tension magneto - when grounded, no spark.
2. Yes, the spark will be more accurate at high rpms. Unfortunately the sparks will be as weak as the sparks from Ford's low tension magneto at low hand cranking speed, so it can be hard to start - more modern high tension magnetos can have a feature called a impulse coupling giving a much better spark when starting the engine.
Can you tell me any more about the impulse coupling? What is that and where can one be found?
Aircraft magnetos use impulse couplings on one of the two magnetos. Every aircraft that is magneto equipped uses two magnetos for reliability's sake. High tension magnetos are not terribly reliable, so the FAA requires two be installed per aircraft engine. There's no way to have a vulture wagon pick up your airplane if the engine quits.
The impulse coupling is a spring loaded device that snaps over the magneto at low speeds to give a hotter spark while starting.
While the magneto in your picture is cool looking it is no more accurate than the original Ford ignition system, and is less reliable.
How do you turn it on and off? That extra wire connector down below the distributor plate gets wired to a switch which switches to ground to kill the ignition. Magneto ignition switches work and are marked backwards of other ignition switches. A usual switch is "on" with the switch closed and "off with the switch open. Magneto switches take the points to ground for "off" so are closed for "off".
A properly set up T timer and coils running on its magneto will run nearly as well as a high tension magneto.
The Bosch (and similar others) are usually much harder to crank start than a timer and coils.
Years ago, I had an original Bosch side mounted drive and DU4 magneto. I really liked it. But at that time there was no one that properly rebuilt T coils. If you had four good matching coils, your car might run great. However random chance was you had at least a couple that ran poorly making the whole car perform not so well. Such a magneto as you show in the photo made a speedster run much better.
!!!!!THANK YOU RON "THE COILMAN" FOR FIGURING THESE OUT AND EDUCATING A FEW OF THE MASSES!!!!!
Now that the proper value condensers are known and available and HCCTs are no longer just shelf art, stock T ignition is a good choice.
As an accessory, Magnetos and mag drives are still great to have and use.
I have an upcoming project car that I immediately wanted a DU4 on it, but I began to think T ignition might be more fun.
Drive carefully, and enjoy, W2
That magneto grounds through the threaded stud on the points cover.
A simple push/pull switch, one side grounded, is ideal except it will be backward....when pulled out the magneto will be "dead" and hot when pushed in.
There are push/pull switches for tractors that operate correctly.
When one of those Bosch mags is done up right you're good for 50 years.
Seth, I just finished a Columbo mag drive with the du4, had a couple issues till I got it running well, I think any mag drive is better for performance than regular T coils but if you want reliability the model T mag and coils will bring you home every time. After the higher rpm range the standard T can not keep up but the mag drive will. When I do my over head project it will have a mag drive on it. Just my two cents worth!
Remember also that most mags are rotation sensitive, the pictured one has an arrow on the oil cap by the input shaft. That arrow shows right (clockwise) rotation when you hold the shaft. Since the Model T crankshaft turns right, the camshaft turns left and the big gear in the drive is fitted to the end of the Model T cam making it turn left too. The small idler gear in the drive turns right and the final output gear in the drive would turn left. Wrong rotation mag for that drive!!! Buyer beware.
Good point Layden.
I have several DU4s in my collection. The DU4 is considered to be bi rotational. The point assemblies were made in clockwise and anti-clockwise configurations. 509a-c is anti-clockwise. 509a-c is clockwise. In the Bosch literature it is sometimes referred to as Left hand rotation (ACW, CCW), or Right hand rotation (CW). You could also re-time the gear, which is also marked CW or CCW OR LR. The arrow has nothing to do with the rotation direction. It means "lift flap here to oil"
Actually, the oil cap arrow was available in the parts book with the arrow pointing either way to designate rotation. When the magneto was new, it showed the direction of rotation, when facing the shaft.
If someone in time has reversed rotation by changing the points plate and re-timing the gears inside,and not the oil cap, all bets are off.
These mags are plentiful, and easy to work on. If you pick one up cheap ,i wouldn't let the rotation bother , as that is easily changed.
Also, i have two running engines with front magneto drives without an impulse coupling. I have picked one up, just in case, but don't see the need on a model T.
Ford "steady by jerks" ignition is the title of a chapter in one of the go fast Model T books from the era. Not only do you want reliable spark at high rpm, you want to avoid using those 16 brittle magnets that could throw a hissy fit at any time.
Failure rate is not the primary reason for dual magnetos in recip aircraft. In addition to full redundancy from the mag to the spark in the hole, dual ignition yields more power. Due to 100LL (Lotsa' Lead) fuel in lower compression engines, I had lots of fouled plugs in the Continental and Franklin engines I owned, but never a mag failure.
Proof of more power from dual ignition: the dual spark plug holes in the higher performance Rajo and Frontenac heads.
Most light aircraft engines built since WWII I've seen have impulse couplings on both mags. They improve the chance of starting quickly.
Another thought comes to me re/ the impulse coupling question. These are also made in clockwise and counterclockwise rotation, so be careful if shopping for one. They need to be taken apart and lubricated and kept lubricated during use. I need simpler at my advanced age , not something more to keep in adjustment. !
I've googled all over the place but I can't find where I would actually acquire an impulse coupling for this thing. Anybody have any ideas?
It looks like the place for the impulse coupling is that gap between the gears and the mag. I could easily make something to just link those together, but if an impulse coupling makes it way easier to start, AND I can find one, why not?
Also - dual ignition would really cool, except in my application with a '14 engine, I don't think it's possible with this set up. If I had the spot on the block for a generator and the high tension magneto just replaced it, then I could see it maybe working hand in hand with the coils/timer. However, this one with the gears takes the timer out of the equation. It'd be really cool if you could have both, synchronize them, but have your switches set up so that you could run on either one or both.
However, at least to me, part of the point with this setup would be to remove the Ford magneto and coil box and drop all of that weight - from just being in the car and for the engine to turn.
The Ford Model K has both HT magneto and buzz coils. Ask the man who owns one.
No, you don't need dual ignition on a T unless the head is designed for it.
The impulse coupling gets oiled from the gear next to it. It really helps to have one on a hand cranked engine. Ron White has a freshly rebuilt mag on his '13. Do a keyword search and send him a query.
Seth, the impulse coupling is built into the magnetos with that feature. Here's an old one sold at eBay: http://www.ebay.com/itm/Antique-International-Harvester-E4-magneto-early-manual- impulse-reset-/281073028664
Just like the Ford system the magnet inside may need charging and the windings may need to be rewound, the capacitor changed etc, but the breaker points will last longer than with a battery system and when properly fixed up, I would say a high tension magneto will work without much more than regular oiling for many miles and many years.
Be aware that the spark plug setting should be less when using a magneto than the standard setting used with coils. Check the specs for the particular mag. Some mags have a "spark gap safety device" but protection is limited and a mag will last a long time if adjustments are right. Check out an article called "Burn out your Magneto in one easy step" in HCCA Restoration Tips. It says ".025 is plenty, less is better".
Thanks for the all the input and info everyone.
Richard, of the little bit of info I've found I did see in a couple of places they recommended .016" - .020" as the gap if you are using one of the high tension mags.
Roger - according to the guy selling it, it works, he tested it and it threw a monster spark across an 1/8" gap.
This seems like a super cool item but I'm really torn. I still need to shorten the drive shaft and torque tube for my incoming Warford, I want a dropped front axle, need some A-C brakes, and the list goes on and on.
Seth, As Bill Cosby says "There's Always room for Jello"
Lol Jay, I love Bill Cosby.
I could spend a gozillion dollars in a heartbeat. And that's just the stuff I know that I want, much less when I stumble onto some cool thing that I've never heard of before - like this whole front plate magneto deal.
At this point, it's all about what can I afford and accomplish before the next tour. I'm pretty sure I can get brakes and Warford done and ready before the summer tour in July. By October I'm hoping to have a top and side curtains made, trunk built, and the body/gas tank/trunk/rims all repainted. (I wanted to go dark green but everyone always raves about the yellow)
And maybe before Christmas I'll get me a sweet Stromberg OF carb from Mr. Howe.
Stopping comes first.
Hang a spare on the rear to give the rear brakes some help, then get the best wheel brakes you can. Front brakes are five times better, but not an off-the-shelf item.
YFAF Yellow Fords Are Faster
I'm already on Mr. Sidmore's list to purchase the next set of A-C brakes that he makes. I believe I'm number 3 in line.
I intend to get a spare rim/tire. I was hoping to find another Sears All State safety tread like the 4 I have, but alas, no joy so far. I'll probably end up just getting a whitewall Firestone.
Unless Bosch changed the design for later units, besides having a pre 1919 engine or the casting that replaces the generator mount, the area where the oil filler fits into takes the earlier type cover with the smaller neck or the Bosch timing cover plate. I had one of these units years ago and had a devil of a time finding a cover plate that would work. Never had it one a car, the gears were too worn out. I wish I still had the mag at least, it was a duel system unit. That means it could start using a coil like a distributor system then you could switch to the magneto.
"..High tension magnetos are not terribly reliable,..."
In most cases, the FAA recommends replacing or overhauling the magnetos at the same 1,600-2,000 hours operation as the engine, so they can't be terribly unreliable. 2,000 hours at 125 mph average is 250,000 miles.
2,000 hours would be a really long time to sit in a Speedster.
Facts trump agendas.
If you buy that unit do yourself a favor and get an impulse for the mag. Those impulses are easily reversible for either rotation.
You will also need a left hand points assembly.
As for the drive coupling it looks like an easy matter to weld on a square on the drive end to engage with the mag coupling element.
Those are excellent magnetos.......
Haha Craig, I'm with you. But I asked earlier and got no response so I'll ask again - where does one acquire an impulse mag for this thing?
Once I have one, where does it actually go?
These folks can probably do anything you want:
Again, not trying to dissuade you from installing a cool vintage accessory but I am disputing the idea that it offers any improvement over the original ignition system. If you have a starter you should be OK without an impulse coupling. Hand cranking probably is out of the question.
I don't have a starter and don't really have any plans to get one.
Here's another pic of a similar (or identical) item actually on the engine. The spark advance levers wouldn't be very hard to duplicate. The main thing I was looking for was how the mag is coupled to the drive, but it's hard to see anything in this picture.
Am I correct in guessing that the impulse coupling would fit in-between the drive and the magneto, or no?
it would prolly be a good idea to keep the spark plug wires off the exhaust manifold... just a thought. mabye im wrong? is this how you get a "hot spark??"
I hand crank my 1912 Overland with a DU4 and no impulse. Works fine.
With an impulse all you have to do is tip it over TDC for a hot spark and if everything is properly timed there are no worries about kick backs either........plus you don't have to pull up on the crank like you're trying the car over........
I got all my magneto parts from Branson Enterprises, Rockford, IL.
^ trying to tip the car over
They make round rubber or fiber magneto couplings of all sizes.
Seth, I don't see and impulse unit on the mag in the photo. Looks like a rubber tube coupler to my old eyes.
That's my old '13 now owned by Ron White. Above is a photo of how it looked before I made it pretty. It was just a standard rubber coupling. Ron now has fitted an impulse... much easier to start
Ricks. The recommendation to OH a mag at 2000 hours does not take into account the maintenance required to get it to 2000 hours. I work on gen av stuff on the side and can tell you I have opened up too many slick 4300 and 6300's to believe they will make 2000 hours untouched.
The life of a mag depends how well the entire system is maintained. The largest killer of a mag is operating with excessive plug gap.
There is a reason unison recommends a 500 hour inspection on their mags. I just installed over $600 in two of them so they could reach that magic 2000 hours.
Btw, I've never seen a set of points go anything close to that. Go with that recommendation at night over rough terrain and let me know how far the seat cushion is stuck.
As a comparison Model T coil points can run 8,000 to 10,000 miles before they need to be replaced according to experts: http://www.mtfca.com/discus/messages/179374/219601.html?1309036151
That's about 300 hours at model T speeds. The timer may need lots of attention in between, depending on type.
Gary, Slicks were originally designed to be throwaways, not rebuilt. Overhaul at 2000 hours does not mean ignore until then. Periodic maintenance is a given. . My planes had Bendix mags, and I got mad every time I had to replace good parts to comply with an AD. .
Excessive plug gap is indeed a killer of mags, and other high tension sources as well. I have replaced two coil packs on Windstars because the rear plugs are a pain to access, so they don't get changed or re-gapped when they should.
Only the Slick 4000 and 6000 were throw aways and then they recommended 900 hours to replace. The slick 442 and 662 were servicable as were the 4200 and 6200 which have since been replaced with the 4300 and 6300 series.
I suspect the $2000 worth of mags on an airplane will require $2000 in parts and labor to maintain in order to reach tbo. The new electronic units are maintenance free but require a mag in the other hole only because it is self supporting and the electronic unit requires ships power.
I'm not a big fan of high tension mags.
If you buy the mag drive, the special front timing covers are being reproduced by Kevin Pharis.
BONUS! Just thought I'd let everyone know I managed to win the Magneto setup from eBay. I've actually already emailed Mr. Kevin about the timing cover. I'll have to see, but I believe that my timing cover will work, it's got a small oil filler neck. Anyway, I'm excited, I'm going to keep my timer and plug wires handy though until I'm comfortable that this thing really works well.
I went thru this a few months back. First off, anything Layden tells you on this subject, you can take to the bank. Steve and Debbie Bellanger at mainelymagnetos are Great! Here is a picture of my rebuilt Mag from them with an impulse.
Compare that to the pic posted by Bill Harris, just two flanges, coupled with a flexible disc like the picture posted by Ed.
The arrow on the oil flap did indicate the direction of rotation at the time of manufacture, yours may have been changed since, mine had. If need be Steve can reverse the rotation.
Also, the impulse coupling came in several different configurations over the life of production, IC 100 and IC 200 ed. 1 thru Ed. 5.
Ed.1 had a totally different drive (Pin Drive) configuration, Ed. 2-5 used an "Oldham Drive" mine is an Ed. 5
As you can see, you will either need a "Driving Member Hub" for the end of your 3 Gear Side Drive and the intermediary "Driving Disc", or as I did, I had a Delrin "Driving Disc" made that bolts to the stock driving flange on the 3 Gear Side Drive mount and is slotted to match the Impulse. Either way you need a flexible connection between the two.
Also, Impulse Couplings come in a range of Auto Retard ranging from 23 to 49 degrees, with the most common being 37 degrees, this can be changed by changing out the cam. Make sure you know how to time the engine correctly for the Impulse.
Best thing I ever did was add the Impulse.
I can help you with docs regarding the Impulse Couplings, DU4, High Tension Mags in general, and proper timing if you wish.
Sweet! Thanks Ron, ill definitely have a bunch of questions. First one, I don't know how fast you usually drive your T, but do you feel like the ignition is any better with your DU4?
Super great post, Ron.
After buying his T, Ron was disappointed that it wasn't quite as fast as his Pantera...
How's your rearend, Ron?
My rearend is still broken Haven't even had time to look at it yet, maybe Saturday.
can't say, it had a DU4 when I bought it, just no impulse....almost impossible to start. But, is is quick! When my rearend isn't broken! LOL
And Ralph is right, not quite as fast as OsoQuik.
OK guys, this is a Model T Forum... Not a Pantera Forum!
Roof looks a little low there, Bill