When will I learn?

I've got one like that I got off ebay too! Well, 3 actually but only one came from ebay... Mine came with the rest of the allen scythe for a total of £1.74 though

It's a shame in a way that the villiers seem to have a lot of ignition problems, the engines themselves seem comparatively robust and let down by it. I suppose I'm moaning too much about them considering the age though.

Nice to see it running, well done mate

Great to see it runs, and yes you right in what your saying the big downfall to old Villiers engines is the ignition system which is a shame and a lot have been scrapped for that reason so good to see you found a way around the problem.
I don't mind you starting a thread about your flymo I'm sure it will be interesting and we could maybe learn something from it and if anyone is not interested or think it's to new well they don't have to read it.

Stu.

Interesting way of doing it, & great to see it works.

Shame I'm not a bit closer, you could've borrowed my old oscilloscope to check out that wave produced by your coil, although there's not much need as it obviously works.

My oscilloscope is an old CRT dual trace model, I got it by posting a wanted ad on my local freegle site. I had to teach myself how to use it & paid $9.95 for an online manual (which I printed off), but it's a fun toy to use for electronics projects.

My Vire marine engine has a flywheel magneto, which has what is called a "Lighting Coil" inside it (I believe it's 6 volts), I suppose what you've done here is a basic form of this, only you're using it to power that motorcycle ignition coil.
You can get voltage regulating chips very cheaply off various eBay stores, I bet if you had the time & the right bits you could manufacture something like this small enough to fit inside the flywheel.

(Almost makes me wish I had an engine with no spark now )

Thanks for the offer, but like you say it's a bit far to travel and seeing as I have 2 crt 'scopes it'd be a bit of a waste of fuel Hooking it up to the 'scope is sort-of the next thing to do, but it means getting one of them out, making a probe as I think all mine are in france (not really an issue as I have some bnc connectors and plenty of co-ax here but it's time), and then finding the time to do it...

The 'lighting coil' you said is on the vire also appears on lots of old motorbikes - they were used to run the lights oddly enough!

A regulator is a possibility I've been considering, I've got some 7812s and 7815s (probably go for 15v as a 'normal' car/bike system runs at 14.4 ish anyway) but the problem would be clamping down the 300v+ of back emf generated by the coil which would just about instantly destroy a regulator - I can do that easily enough with a diode but I'm not entirely sure right now if the coil would still work properly like that. As it was when running in the video, the ignition coil is running on AC from the 'lighting coil' - the waveform peak is timed to be at the right point by design (otherwise the original coil wouldn't work) Using AC shouldn't hurt an ignition coil if the voltage isn't too high.

There's quite a bit of playing around to do - I could just leave it as it is and be satisfied it works, but I'm a bit picky really.

There's a UK seller on eBay who sells scope probes for around £3. They're pretty good & arrive quickly. I got some from China for a similar price, but got fed up waiting for them to arrive, so got a couple from the UK seller.

TBH my electronics experiments have taken a bit of a back seat since I got into the Tarpen, I was on a very steep learning curve with it all (it's quite different to the electrics I was used to) I probably should've kept my hand in.

Without wishing to jinx it, serendipity appears to be smiling on me recently - engine wise at least...

I dug out a 'scope and made a probe for it - I had a few minutes spare so thought I might as well just get on with something!

The engine started just as easily as in the video, first pull from cold again

I'd put the rectifier diode in so I could get sensible measurements and stuck in the probe - I'm getting a nice wave and just a shade over 8 volts AC at running speed. I'm happy to leave it like that and run it without the rectifier - also no need to regulate either. The ignition coil seems perfectly happy too, it's not even getting warm which is a good sign.

If I decide to make the coil a bit prettier by rewinding it again then I could even get away with some more turns to get a bit more voltage. It doesn't seem strictly necessary given how easily it starts though. That's with this ignition coil, I may need some more juice when I put the other one on - I'll find out later and given how easily this engine is distracting me that might be tonight.

So I declare the ignition just about sorted now. Let's get the JAP done and I can move on to this - or one of the other things in the 'to-do' pile

We had some family visit tonight, so while they busied themselves with the kids I retreated to the garden to do this...



I put the other coil on! I had to make a new HT lead as I couldn't find one... Still, I had the correct terminals so it wasn't a problem.

This is a random coil from some type of car - a friend gave it to me the other day when we were talking and I said I was looking out for one. I think it'll look much better cleaned up than the motorbike one that was on there earlier.

I spun it over without the plug in and while it's still not great at such a low speed it's actually marginally better. I think it may be for a ballast system, so it's designed around approx 9 volts rather than 12 which suits this perfectly.

Again, it started on the very first try and ran happily for about 3 minutes on the amount of fuel that fits in the short piece of hose before I shut it down. It really is a bit loud though and the exhaust sounds quite 'harsh' - the exhaust is just a bit of square tube with a smaller bit on the side so I think there is a significant lack of back-pressure. The valves would benefit from a bit of a lap too as while they work they could be better.

So now the to-do on this one is:
make or source new exhaust,
sort out a cowl,
strip,
clean,
service,
rebuild,
make the wiring look pretty.

I need to 'find' a cap for the fuel tank too - the tank is fine, as is the tap, just missing the cap - I'm sure one'll turn up somewhere. It's not a massive challenge and is turning out to be looking a lot easier than I thought it would be when I bought it.

Apart from some playing when I feel like making some noise this is going on the back burner for a while until I get some other bits sorted, I'll update as and when anything happens.

Paul

Good work, & at last! A use for a ballasted coil on something old!

I was going to suggest an old 6v motorbike coil, as they are smaller, but with your scope findings it sounds like you've got things pretty well matched. Also, old 6v motorbike coils can be expensive & hard to find, as my dad found out when he needed one for his Velocette a while back.

There's a company local(ish) to me who claim to be able to take an old magneto & replace the innards with some kind of electronic ignition system (not full electronic, I believe they still use the points). I wonder if they're doing something similar to what you've done here?
I know it runs without a battery. I think they start at around £155, so most mag coils could be re-wound for less, but they claim even a re-wound mag can start to fail after just 12 months (but they would say that, wouldn't they? ).

Good to know you made it work, if I ever need to try & do the same or something similar I've got loads of enamelled copper wire knocking about after my previous experiments. (Notice I say "try" & do something the same )

Paul this is great, just the sort of crazy thing I like to do, electronics can be great fun when applied to real life. Can't remember if your going to purbeck or not, if you are I have a spare bridge rectifier IC you can have if you want to convert it to full wave rect without soldering 4 diodes together

Great little project to follow and a good read
Andy

PS re back emf, try a 2nf x rated cap across the coil and as far as mods go and not being original who cares, your having fun

It's actually very simple to do, just hard to explain...

I really lucked out with the voltage level, I pulled the wire off the generator armature and the decision for the length to use was 'how wide is the garden' I put one end in a vice and gave the other end a tug to remove any little kinks etc. and wound it up.

I've actually got a few engines of various makes with dead coils so I'll probably end up doing the same thing to them - I might even be able to come up with some sort of 'process' so there is less experimentation with each different flywheel mag. If I ever get a dead external magneto I'll give it a go with that too!

As for the 'electronic' conversion, I think I've found the one you are on about. If so, it does need a voltage source to power the coil and simply converts the mag to a battery&coil system, with no points (electronic pickup). It's actually exactly the same idea as the 'lumenition' systems (remember those?).

I don't see why a rewound mag would only last a year though, unless it's not been sealed properly.

blackvanman wrote:Paul this is great, just the sort of crazy thing I like to do, electronics can be great fun when applied to real life. Can't remember if your going to purbeck or not, if you are I have a spare bridge rectifier IC you can have if you want to convert it to full wave rect without soldering 4 diodes together

Great little project to follow and a good read
Andy

PS re back emf, try a 2nf x rated cap across the coil and as far as mods go and not being original who cares, your having fun

I'm not sure if I'm going to Purbeck yet or not, I have to see what finances say about it...

I couldn't use full wave rectification as it is, I'd have to lift the currently grounded end of the coil so it's fully floating and then rectify that. I might be doing that on a different engine though so thanks for the offer, if I do come down it'll be useful!

For the back emf issue, I was thinking about a 1000v piv diode reversed across the coil to clamp it, like is used on some relays in RF applications (who would've guessed I'm a radio ham too...) - I'm pretty sure it's not necessary now though - it all seems happy as it is.

As for the modifications, I'm not too bothered about it. I'm not sure I'd be happy to do anything that I couldn't reverse easily (i.e. no hacksaw action!) but chopping and changing bolt-on bits isn't an issue to me. I'm more concerned with having something working rather than being original and broken.

lol i was wondering
I have a br92a sat infront of me right now, will try to put it in the van in the morning that way if you go you can remind me and i can try to remember where i put it

73 de M0IED

ok just been scanning the forum for my previous posts lol, how did you know?

Lucky guess I suppose... To be honest I didn't have anything more than an inkling based on your suggestion of suppressing emf using a cap

73 de M0XKO (by the way, I really should get around to updating my qrz profile before you say anything...)

Well I have to admit this is all going over my head
I does sound good what your doing and I hope it all works out for you.

Stu.

my mate has a hot box which he uses a ballast coil in....he uses it to run his engines at shows...
another use for the faithful old British coil.....
mike....

To keep you all amused there's going to be another thread soon involving more electronics!

pauldg wrote:To keep you all amused there's going to be another thread soon involving more electronics!

sounds good to me..should make interesting reading......thanks for letting us know......
mike.....

pauldg wrote:To keep you all amused there's going to be another thread soon involving more electronics!

Maybe keep it to layman's terms then eh?

Ianhw77k wrote:

pauldg wrote:To keep you all amused there's going to be another thread soon involving more electronics!

Maybe keep it to layman's terms then eh?

No problem. As a quick overview I'm wiring a special switch to a silver lump to control a black twiddly thing and a clicky box in the hopes of making a rusty lump go 'vroom' and 'ffffffffffclick'...

How's that?

Seriously though, it's going to be an automatic control system for the compressor I'm building.

how ever you want ian..fine by me..lol

mike...

I knew someone who made one of those from an old drum brake slave cylinder acting against a pushbutton switch, but he was pretty old-school that guy, for his receiver tank he used an old gas cylinder which had been run over by a forklift (or something like that), he pressurised it to get the dent out, can't remember by how much, but I do remember him saying it went with a bit of a bang.

To say he didn't "do" health & safety was a bit of an understatement, lovely bloke though, he was the one who gave my brother & I the old Briggs & Stratton. I have no idea if he's still around.

Talking about electrics, I got the Homelite apart a bit more today. I would be interested in your input Paul. I haven't updated the thread yet, but will do it either tonight or tomorrow. Would be good if you could cast your eye over it, let me know what you think.

I think I'll start a new thread for it in a minute, pics will have to wait though...

As for the Villiers, I'm still deciding what it's going to do when it's finished. I'm sure I'll come up with something fun.