Timing 1910 Hupmobile

I have finally suceeded in replacing the Bosch DU4 Fixed magneto with a variable timing one . I have spent the last few weeks experimenting with start and run settings . This has been complicated because the engine is very sensative to small movements of the ignition setting lever I probably need to devise some sort of bell crank system to allow more movement of the lever to less movement at the magneto . However I discovered a very effective way of sorting optimal settings out today. I had morning tea with my local mechanic who suggested we just put a timing light on the car . We used a spare 12v battery as a power source , Marked TDC with white paint on the flywheel and clipped on to Lead One as normal . It was amazing and worked perfectly. Using the normal marks on the cylinder block face I now know exactly what position of the lever corresponds to the orginal mag setting (which not surprisingly allows the car to start and run well) and I can also see that there is still plenty of advance from this position to allow me to experiment with if I wish. Karl

Using the normal marks on the cylinder block face I now know exactly what position of the lever corresponds to the orginal mag setting (which not surprisingly allows the car to start and run well) and I can also see that there is still plenty of advance from this position to allow me to experiment with if I wish. Karl

What have you found for optimal timing when running?

It depends- starts and runs best at idle as set up by the factory . For running runs best at a setting slightly more advanced than this .

As I have said previously the factory instructions seem to set up the fixed ignition slightly retarded after TDC which sounds a little strange to me . I set up the ignition with the magneto fully retarded and the flywheel in the same factory position for fixed ignition set up . -Seems to work for me- I initally set the magneto up fully retarded on TDC (as most cars of the period did) but never seemed to run right and was quite sluggish for some reason ??? Karl

Thanks for the reply. What position did you settle on for best power while under way?

I just set mine up and it is currently at 15* BTC. To do that, I located TDC exactly, then measured and marked degrees on the flywheel.

This is interesting. What I know about (modern) IC engines is that lower compression slows combustion. The Hup has something like 4:1 compression, and those definitely aren't "fast burn" chambers! So with modern cars running from between 30-40* of advance, it seems crazy that the Hup wouldn't benefit from al LOT of advance.

What I'm getting at is that I feel that if I leave the timing where it is -at 15*, it's too retarded and leaving a lot of power on the table. But that seems to go counter to what you've experienced. Having the timing marks and adjustable timing (the way you have yours) is an awesome way to dial it in to "feed it what it wants".

Tom Mine would be about 15 degrees BTC when running nicely Some one has (hopefully accurately) marked 32 degrees BTC on the fly wheel and the sweet spot is about midway between this and TDC . I did get a very detailed PM from a knowledgable lister regards this issue . Essentially what I think he was telling me is that even though you have a range of advance and retard on the interruptor housing as you advance more and more you end up getting less current produced by the magneto as you go outside its optimal pole positions for production of current so there is little to be gained by over advancing . I have a Mod 5 DU4 which apparrently has different ? extended pole pieces so that this is less of a problem Hopefully he will read this and correct me if I am wrong -Karl

Thank you for the reply Karl. Your post was fantastic. You just basically confirmed four things that I had suspected, but wasn't sure about.

1. I've wondered about the timing of the points opening, relative to spark intensity. It only makes sense that the best spark will be produced if the the points open when the energy in the armature winding is at it's highest point...and modifying the points' opening away from that will only progressively weaken the spark.

2. That being the case, my comment above about modern cars' combustion chambers and timing may still be true, relative to the Hupp. If your power/drivability tapered off using more than 15* of advance due to the points opening event moving too far away from the armature's peak excitement event, then indeed, as i suspect, the Hupp may actually "like" more than 15* for optimal power and drivability.

3. My dad used to talk about advancing the timing "one tooth" on the mag>cam gear relationship to get more power. I think that he was FOS about that now. It's hard to see the gear teeth when engaging them b/c of that aluminum gear cover, so confirming absolutely that you installed the teeth the way you THINK you didn't isn't easy (w/o using a timing light). If you truly advance the timing one full tooth, that would be a LOT of advance. I think you'd have a very hard time starting the car. I am going to check today, to see how many degrees each tooth equals.

4. If I am correct in 3 above, then there is really only one tooth that is "right", and setting up as per the manual is the only way w/o profound lack of power (one tooth retarded) or profound kick-back when cranking (one tooth advanced). It would be nice if the teeth were cut with a much closer pitch so you could adjust at the gear, but I don't think that you can. I will do some looking and report back.

Thanks again for the great post, Karl.

-Tom

Thank you for posting and please don't pull your post -If you do that then your excellent knowledge will not be passed on and our whole hobby suffers. Karl

Amen to that .

Ken

I fiddled about with magneto timing a while ago and came to the conclusion that there is no point in advancing or retarding the spark. I read somewhere that with low compression engines it isn't an issue. From Edgar

Hupmobile wasn't alone in using a "fixed" magneto timing. My Metz 22 uses the same Bosch magneto as the Hupp. The magneto was the costliest thing in their parts catalog at $60. I doubt the adjustable magneto would have added that much cost to the car, so was the "fixed" timing used for safety and simplicity only?

Phil

Hupmobile wasn't alone in using a "fixed" magneto timing. My Metz 22 uses the same Bosch magneto as the Hupp. The magneto was the costliest thing in their parts catalog at $60. I doubt the adjustable magneto would have added that much cost to the car, so was the "fixed" timing used for safety and simplicity only?

Phil

I read up about this issue. The point is that there is no advantage in low compression engines of advancing or retarding the spark. It makes no difference, and that is what I found out with my car.

Edgar

Man...that is definitely NOT inline with my experience with engines at all. Timing has made enormous differences in everything that I've ever worked with, but I admit that my experience playing with timing on brass-era cars is limited to adjusting the timing from the steering wheel of our '10 Hudson which also made a huge difference.

It's so easy to go back in time 100 years and second guess an Engineer at an automobile factory.

In 1909-11, variable timing magnetos were available, and at minimal additional cost over fixed timing.

Yet the Engineers at Hupmobile looked at alternatives and decided fixed was best.

I've owned and driven a fixed timing Hupp for 36 years, it works, my car will do 40-45 all day long, why mess with it? Fix other worn- out problems and leave the design alone, and you'll be happy. A drive train that's worn put will suck more horsepower from your car than timing ever will....

"No difference" and "not finicky" are two different concepts.

I drive a fixed Ignition 1910 car with widely spaced gears and wish that I could retard occasionally to improve low-end torque. As it is, the motor is rather peaky meaning that you have to keep the revs up for good performance (almost modern). It definitely sweetens up at about 1100 RPM and is a bit boggy below 800 or 900 RPM. This might be due to other reasons than spark timing though since there is some positive overlap on the valves. It is fortunate the other models in the range with exactly the same design engine (Combustion shape, compression ratio, spark plug and valve location etc.) but larger bore (same stroke) have automatic spark and the factory gives specifications that can be compared among models.

Fixed Spark fires 20-22 degrees Before Top Dead Center

Automatic Spark fires 26-31 degrees Before Top Dead Center at (centrifugal) full advance.

N.B. The advance suitable for this design (OHV) is probably less than needed for the Hupmobile (SV) so DO NOT use these numbers as applicable to your '20.

So it seems that they run the fixed spark a bit retarded compared to ideal high-speed timing as a compromise among starting, low end, and high end performance. But the larger bore may need a degree or two more advance so the difference may not be a sever as first seen.

A friend with the same year and model added variable spark and claims that overall drive-ability and performance were NOT improved by the modification and he wishes that he never did it since it involved drilling holes. Another freind with a similar but earlier (vibrator spark) car swears by the (stock) advance lever and prefers it to the throttle for overall control of the engine.

The reason that the Factory gives for using fixed spark or automatic advance on all their cars is that it relieves the operator of another control to make driving easier. That is the officical reason, but if you read between the lines in their literature including dealers letters to the factory, the real reason might be that drivers generally ran too far retarded and the engines overheated.

They say that the small engine is easy enough to crank with a fixed spark but the larger engines need a retarded spark for safe starting.

Note that the centrifugal advance is on the INPUT of the mag so that no loss of spark intensity is created by the advance-retard scheme.

I am quite aware of the theory but I go for practical results and I have tried various things but do what works well for me. e.g. I got a huge boost to performance by opening up the tappet gaps from what is considered the normal of 6 and 8 thou. to 18 and 20 thou. These ancient cars have have their own conventions!!

hello,my name is Ferruccio, I write from Italy. I also have a "20", that slowly I am making.

I had a lot of trouble with the magnet and I decided to change it all, before I mounted an adjustable magnet (bosch DU4) but with the heat of the engine after a bit of road, does not work anymore.

I decided then to change again by mounting a spark gap and a modern reel.

my setup pre have the engine ready and powerful enough to anticipate a tooth was the crankshaft, ie compared to the manual that shows a line slightly shifted the pms of my engine is perfectly vertical, in this way with a stroboscopic lamp I could adjust the advance about 10 ° before TDC.

I have implemented many changes to my car, bearings, valves, electric fan, oil breather, gear cover magnet, and I guess I'll do another.

I am happy to share experiences if anyone interested in my work.

greetings to all

I have a problem instead of the bushings, and I would like to install pistons to increase compression slightly. I found on the internet some pistons for the model t.

does anyone know if the measurements are the same? that parts of the engine mode t have in common the hupp 20? piston-connecting rod - crankshaft-bearing?

Looks like you have model T hub caps ? Different threads .

Welcome to the discussion

Ken

A very nice picture of a 1910/11 Model B Hupmobile. I have just restored a second engine for mine having broken the crankshaft of the first one. I Use Chrysler/Dodge (1930s) alloy pistons with an extra oil scraper ring and you will have all the compression you want. I just ran my car with its new engine for the first time this week and with a new cam shaft and valves it has power. (Always declutch before applying brakes because of the heavy flywheel on the front of the engine. That is the lesson I learned from breaking my crankshaft)

Set the valve timing as follows: TDC on the fly wheel 10mm to the right of the line of punch marks on the front of the cylinder block, looking from the front of the engine. With No.1 piston at the top of its compression stroke, the exhaust valve on No.4 cylinder will already be starting to open. You will need about a 2mm thick cork gasket between the side plate and the crankcase. Set inlet valve tappets at 18 and exhaust tappets at 20 thousandths of an inch. I do not kn:)ow what that is in mm.

The shelac on the winding of your magneto melted with age when it got hot. That is why it stopped working. Get it re-wound and it will be good again. The spark timing should be set at 15 degrees before TDC. There is no advantage in having an adjustable spark on low compression engines like these.

Keep in touch, Edgar

I made all the crankshaft bearings for my 1910 Hupmobile and I am only a hobby mechanic. I got a professional to machine bronze sleeves for the main bearings on a lathe, rear gearbox bearing included. Then I made up a jig out of a steel plate, with aluminium cores smaller than the finished article. I melted diesel grade white metal in a small cast iron glue pot on a gas ring. I heated the jig with bronze sleeves in place to 200 deg. C using a propane torch and infra red pyrometer and poured the white metal into each bearing dibbling it as I poured with a piece of straight wire to make sure no bubbles formed and 'presto' there were my bearings. I took them back to the machine shop with the reground crankshaft etc. and had the white metal machined to precision size. I cut the big end bearings in half with a slitting saw on a small milling machine (el cheapo drill/mill) and shimmed the gaps. For the centre main bearing I got two made so that I had two perfectly fitting halves to fit tightly in situ.

Next I made oil grooves in the white metal using a Dremel.

If you feel daring enough to do this sort of thing I can give you more advice, Edgar

Saluti, Ferruccio. What bearings did you use in your differential?

Phil

I used Timken roller bearings, numbers as perviously given

the procedure for commissioning phase is the same that I've used. is the best for the performance of the engine, the valves were captured at 0.25 mm.

the magnet although rebuilt qualdo warms always problems, I've had experience on other machines in the past, the best solution is to mount a spark gap.

(I know it is not original but my intention is to use the machine in the demonstrations or Sunday to go eat ice cream without any trouble),

for the construction of the bushings I rely on a technical workshop in the industry I do not have a chance to do in my workshop.

I mounted the bearings in the differential in mm being in Europe is almost impossible to find in inches, are still in all its original, I mounted instead shielded bearings on the shaft so that the oil does not reach the brakes, as well as on 'I mounted shaft bearings shielded to prevent the passage of engine oil in the differential.

the hubcap are those of a model t because I rebuilt the hubs, I have adapted those because at the time I had nothing else, they are the cheapest I could find and can be installed easily.

apart from the rest of the drive shaft is rebuilt again, gears, brakes, bearings, and various modifications to avoid sowing oil everywhere.I also built a tank to contain the oil leaking engine. when I take part in the demonstrations and go in the historic centers of Italy do not like oil stains!

if you want to find me on facebook my full name is "telò ferruccio" my e-mail address is "ferro.81@hotmail.it" here I can not upload photos of my changes but who cares I send more than willing.

some photo I have also sent to Mr. Brian Spear if they could help someone Hupmobile club member.

Greetings to all and thank

This is what being person is all about. We help each other when possible.

Hi again,

I pulled the magneto off my Hup and noticed that the drive sprocket was not "keyed" onto the magneto shaft. At first I thought this may be a problem but then I thought that maybe this would be one way of fine tuning the spark timing given that on these cars, the spark timing is fixed. Or would it normally have a key to stop the sprocket from slipping on the magneto shaft? I am strongly contemplating replacing this magneto (an unknown quantity) with one I know to be good and that has variable spark timing.

Cheers,

Andrew.

Hi again,

I pulled the magneto off my Hup and noticed that the drive sprocket was not "keyed" onto the magneto shaft. At first I thought this may be a problem but then I thought that maybe this would be one way of fine tuning the spark timing given that on these cars, the spark timing is fixed. Or would it normally have a key to stop the sprocket from slipping on the magneto shaft? I am strongly contemplating replacing this magneto (an unknown quantity) with one I know to be good and that has variable spark timing.

Cheers,

Andrew.

The magneto gear should be keyed onto the shaft. Variable spark timing is something that really bothers people experienced with later model cars. It is not an issue with Model 20 Hupmobiles because of their slow revving and low compression. Simply take the cam sleeve off a DU 4 magneto and turn it around so it is on fixed spark. The points need to be set at 15 thou, making sure the two cams are the same. If the cams are no the same a shim will be needed under one cam. It is easiest to set the points gap using another magneto on the work bench rather than lying under the engine.

With the flywheel at 3/8 inch past the punch marks on the front of the cylinder block, and No 1 piston at top dead centre, the magneto is set to engage with the valve timing gear having a gap of 3/8 inch between the armature and magneto case as seen when the magneto cover is removed.

Edgar

My Bosch DU4 magneto shaft has two key slots, which the magneto shop discovered only after it was disassembled. They made an educated guess of which slot to use, but you might want to mark the shaft before pulling off your gear.

Phil

My Bosch DU4 magneto shaft has two key slots, which the magneto shop discovered only after it was disassembled. They made an educated guess of which slot to use, but you might want to mark the shaft before pulling off your gear.

Phil

I think you will find the two slots on the magneto shaft give an option for timing the magneto with the valve timing gear if the armature does not provide the required 3/8 inch gap between it and the magneto case, as I previously described. Therefore check out that the gear on the magneto is on the correct slot before covering the gear with its aluminium cover. These are all traps for the unwary! With the magneto correctly timed the engine is easy to start. When it is wrong, life is a misery.

Good luck, Edgar

Hi Edgar and everyone,

The method of setting the magneto to engage with the valve timing gear described by Edgar sounds a simple and useful one. However, I'm not sure I understand where the "gap of 3/8 inch between the armature and magneto case as seen when the magneto cover is removed" is. I have attached some pics of the Bosch DU4 I intend to use on my Hupmobile 20 and would really aprpreciate if someone could point out the gap Edgar is referring to. Any comments regarding the general condition of the magneto are welcome too!

Regards to all,

Andrew.

None of your pics are ideal for here you want to be looking. Looking at this pic for reference:

...See the white porcelin item that looks like a mushroom? Take that off (slide the spring steel connector off of it first). The long skinny black thing above it -called the "pencil", remove that by sliding it toward the distributor side, then pull it out toward the gear/drive side. Then the cast plate that the white "mushroom top" was on, pop that up/out and you'll be looking down and in, at the armature. You want the magnet part of the armature, 3/8" past the inside of the case/casting.

EDIT...see if this pic shows, and clarifies what I'm trying to say, better than words...

Tom - thanks very much for that explanation, that all seems clear. I'm looking forward to getting my hands on a copy of that book - hopefully it is in the mail!

Thanks again,

Andrew.

Tom - thanks very much for that explanation, that all seems clear. I'm looking forward to getting my hands on a copy of that book - hopefully it is in the mail!

Thanks again,

Andrew.

Hello Andrew,

That is a rather late edition/version of the DU4 with advance and retard.

It is also a CLOCKWISE Magneto by the terminology used in the magneto world where the reference to rotation direction is at the driven end. Note the arrow pointing to the right on the oil flap near the gear. Also the points are definitely for a clockwise machine. I note this because the hand written note in the manual indicates that a Counter Clockwise (Left Hand) magneto is used.

Back to the problems with using a later mag for a fixed system: It is traditional to lock the advance lever to as far advanced as possible when using a mag with advance/retatard in a fixed ignition system such as the Hupmobile 20. Advance is swinging the cam-box lever in the opposite direction of rotation. This is the position where the points break the current (and magnetic field) at its maximum point to give the hottest spark. The Fixed mag original with the car was preset to this situation so no worries..... But the early variable timing mags lost intensity when the lever was not in the proper position.

Bosch figured out that by extending the pole pieces that they could broaden the current peak and the fall off when retarding would not be much of a problem. This was done on DU4-Mod 5 mags in the brass era and off and on later in DU4 world depending on what application of the magneto was used.

What this boils down to is that when you remove the dust cover (part you MAY see extended pole pieces and not be able to position a ruler (scale) as shown in figure seven. (Note that the rotational position shown in figure seven is NOT where the points break at the max spark.)

I would be interested to see what is under the cover of a DU4 Ed 19 v8 since that is much later than anything that I have worked upon.

The drive shaft on my mag has two key slots to allow adjustment of the timing. However recently I had some problems with the nut undoing on the end of the shaft (probably because the magneto and hence shaft was originally clockwise rotation and converted to anticlockwise - meaning the drive shaft nut wants to unwind all the time). My friend who is a motor bike engineer (and does design consulting working for Ducati) rebuilt it for me . Interestingly he tells me that if the taper is right on the shaft then no key is required and the gear will not slip -friction holding it in place . We re-tapered the shaft but still keyed the gear. Karl

The drive shaft on my mag has two key slots to allow adjustment of the timing. However recently I had some problems with the nut undoing on the end of the shaft (probably because the magneto and hence shaft was originally clockwise rotation and converted to anticlockwise - meaning the drive shaft nut wants to unwind all the time). My friend who is a motor bike engineer (and does design consulting working for Ducati) rebuilt it for me . Interestingly he tells me that if the taper is right on the shaft then no key is required and the gear will not slip -friction holding it in place . We re-tapered the shaft but still keyed the gear. Karl

The nut is the same on CW and CCW Bosch magnetos of the period. In fact, the only part that is not the same is the breaker plate (and stamp on the oil flap). Many other parts need to have their relative positions shifted when going from CW to CCW but the parts are the same. This is why the only way to tell CCW from a CW after all these years of potential conversion is to look at the breaker. The Mag Pictured above has a CW breaker.

The 1910 Bosch book says that no key is needed if the tapers are accurate. I still use a key since the consequences of slip are so dire and it is not an easy thing to get to while on the side of the road.

Douglas used a key on the taper for their flywheels until the mid 20's when they decided that the key rolling out and gubbering up the shaft was worse than the possibility of a bit of slip occasionally. But the flywheel as no timing function so slip is no big deal. (I rolled the key out on my 1910 and it was not an easy fix. Now I do run without a key.)

Hi 1910_Anon,

Interesting - I'm glad I posted the photos! Can I use a clock wise magneto and reorder the spark leads to get correct firing order? I bought this magneto for another car I have (a Minerva) but was told it was from a Hupmobile. As it looks in better condition than the one that came with my Model 20, I thought I would use it. However, if I can't use the clockwise one, I may have to use the orginal one.

Will send some pics of under the cover when I next get the chance.

Thanks again. Another example of how useful this forum is. I apprciate it.

Regards,

Andrew.

Hi 1910_Anon,

Interesting - I'm glad I posted the photos! Can I use a clock wise magneto and reorder the spark leads to get correct firing order? I bought this magneto for another car I have (a Minerva) but was told it was from a Hupmobile. As it looks in better condition than the one that came with my Model 20, I thought I would use it. However, if I can't use the clockwise one, I may have to use the orginal one.

Will send some pics of under the cover when I next get the chance.

Thanks again. Another example of how useful this forum is. I apprciate it.

Regards,

Andrew.

Just changing the order of the HT wires will NOT do it.

The breaker assembly for the CW and CCW are mirror images of each other. If you have the original mag, place it side by side with the one pictured and you will imediatly see the difference. If you have a good CCW breaker plate assembly, you could convert the magneto in the picture to CCW since the only functional part that is actually different is the breaker assembly. BUT you have to do some serious disassembling to re-time the 2:1 gearing between the armature and the distributor plus the breaker cams have to be shifted to the "other set of holes" Not a job for the feint of heart.

What is the story of the original one?

Hi again 1910_Anon,

I checked the magneto that came with my Hup and it has CCW points (although the arrow on the oil flap points to the right). I built a simple magneto tester (the design of which I stole from the Model T forum!) and I get a nice blue spark for each terminal so I am happy. I am also including a picture of the tester in case any one is interested.

Thanks for your information - I am learning all the time...

On a related matter, can anyone tell (or show) me how you wire the magneto up to the switch on the dash???

Regards,

Andrew.

The switch is merely a ground, so there's one wire from the switch to the magneto, and one wire from the switch to engine/frame ground. When the switch is in the off position, contacts are made to ground the magneto thus killing spark to plugs.....

Hi again 1910_Anon,

I checked the magneto that came with my Hup and it has CCW points (although the arrow on the oil flap points to the right)

Hello Minerva,

Your breaker arm is from a DR magneto.

The Difference is that the DU uses metal cams and has a fibre block on the breaker arm. A DR uses fibre (roller) cams and a metal arm on the points. In all cases, metal-to-fibre. I have seen where someone went fibre-to-fibre (DU breaker on a DR Mag) and it wore out very quickly but have never seen metal-to-metal but can safely say that Bosch never used that scheme. Given that your mag was changed from CW to CCW at some point, the wrong style breaker arm is not surprising.

You may want to put a tiny bit of Vaseline or dielectric grease on the cams to compensate for having metal on metal. (Or change over to DU points. A DR cam box will not fit on a DU Mag or vis. versa) There are oil wicks on the cams but they are not designed to lubricate metal on metal breaker arms

What is the serial number of your mag? It looks much later than the car. Is the Cam box Fixed against rotation?

Trimacar has it right.

I will expand and explain: The wire from the switch to the Mag goes to the terminal on the points-cover and shorts out the head of the screw at the center of the Breaker plate to ground which will kill the mag. There is a small metal brush on the points-cover to make contact with the rotating screw (head). That screw is the electrical connection between the Low Voltage (primary) side of the armature and the points so you do not need High Voltage (secondary) wiring for the kill switch.

Thanks again 1910_Anon and Trimacar,

Will try and track down a set of DU4 CCW points from somewhere, however, will see how I go with the points I have now. Will dab a bit of Vaseline to lubricate. 1910_Anon, the serial number of the magneto that came with my car is 3523759. It also has "DU4 Ed. 18" stamped on it - "Edition 18" maybe?

Thanks for the info on the switch wiring, I guess what I was wondering about is the arrangement of the wires on the actual switch terminal post. It only has one so are the 2 wires separated by an insulated fibre washer or similar?

Regards,

Andrew.

Thanks again 1910_Anon and Trimacar,

Will try and track down a set of DU4 CCW points from somewhere, however, will see how I go with the points I have now. Will dab a bit of Vaseline to lubricate. 1910_Anon, the serial number of the magneto that came with my car is 3523759. It also has "DU4 Ed. 18" stamped on it - "Edition 18" maybe?

Thanks for the info on the switch wiring, I guess what I was wondering about is the arrangement of the wires on the actual switch terminal post. It only has one so are the 2 wires separated by an insulated fibre washer or similar?

Regards,

Andrew.

Hello Minerva,

The Shell of the switch goes to ground. This was originally done with something that looked like a hose clamp on the large diameter threaded portion but using a big ring terminal under the nut works fine also. The terminal at the end of the switch wires up to the magneto.

Ed 18 is very modern for this car. The original magneto was probably a Mod 1 or Mod 2 (all brass) with a serial number somewhere around 500,000.