Okay, so here goes.

I have a Lister D stationary engine that creates its spark by running a magneto.
It does create a spark, but I want a better one!

Without going to the expense of rewinding the coil my question is, can I stick a few neodymium magnets on the outside of the magneto case to help with the magnetism?

Would this work?
Is there any reason why it wouldn’t work?

I would get the whole case remagnetized but don’t have the machine to do this in my toolbox and think building one is way beyond me!

So any ideas?

Thanks.

 

can I stick a few neodymium magnets on the outside of the magneto case to help with the magnetism?

What material is the case made of?

 

Metal!
It’s what they call the hovis rs1 type mag from Lucas.

 

Metal!

Is this metal ferro-nagnetic?

 

I have no idea what that even means?!
I do know it has the magnet stripe embedded into the casing, if that helps.
It’s a dull Aluminium type metal, almost a pewter metal type shine.
I will try and google it and see.

 

I have no idea what that even means?!
I do know it has the magnet stripe embedded into the casing, if that helps.
It’s a dull Aluminium type metal, almost a pewter metal type shine.
I will try and google it and see.

Just see if a magnet is attracted to it.

 

Probably best to see if you can stick your magnets on the casing to see if it's Ferrous metal..

 

I don't think magnets will affect your spark at all. The construction of a magneto is similar to the construction of a power transformer. Every effort is taken to "funnel" the magnetic fields through the coils via the transformer core. This minimizes the possibility that any outside magnetic fields will affect the coil.

I will note that magnetos are very sensitive to variations in the gap of the contacts. Too small or too big, even by a small margin, can reduce the spark energy. If you think it through, that also affects the timing of the spark, further reducing proper fuel ignition. Too small a gap will push the spark later in the cycle; too large will cause it to fire early. Check the gap before you try anything else.

There are a few forums out there that discuss Lister engines. Look around on the web, you'll find some experienced Lister operators that can give you good advice.

 

I belong to a few of the lister forums, but as my question was to do with the workings of a magneto, So I though the best place to ask was here, where the experts are!
The magnet idea just crossed my mind, and I just wondered if it would make any difference.
Now I know it won’t!!
On another Lister question I can’t find answered on the lister forums is the rating of the condenser that is inside the mag.
You can buy ones that actually say they are for a lister for about a fiver, but car ones are so much cheaper, and I don’t have to wait for it to arrive in the post. But I can’t find out anywhere what rating it is, or even how to work out what one I need.
Any ideas on this?

 

I don't know what is needed in the maneto but I would wager that car ones will be cheaper because demand will be higher.

 

With magneto ignition condition and adjustment of the breaker points makes a big difference, as well as the air gap between the moving and fixed parts of the magnetic circuit. Fortunately those are easy to address. Re-flashing the magnet may be useful but takes a setup that very few possess.
And an addition, which is that I did indeed forget to mention that capacitor (usually called a condenser) connected across the breaker points. If that item is not right the spark will be weak.

 

But I can’t find out anywhere what rating it is

The magneto condenser (aka capacitor) is doing a similar job to a car one, so you could try a car one.

 

But I can’t find out anywhere what rating it is

Now that you mention it, any time I've looked at automotive or small engine condensers, there's no mention of an actual capacitance value. A quick poke around the web shows suggestions from about 0.1uF to 5uF. Due to the coil being involved, voltage ratings from 450 to 800 volts.

A leaky cap will weaken the spark so that's something you'll want to confirm as good early on.

 

A leaky cap will weaken the spark so that's something you'll want to confirm as good early on.

I don’t actually have a cap, it’s just a tab that goes over the spark plug end, so that connection is fine.

As for the condenser, is there much difference between a 0.1uf and a 0.5uf?

 

I don’t actually have a cap, it’s just a tab that goes over the spark plug end, so that connection is fine.

As for the condenser, is there much difference between a 0.1uf and a 0.5uf?

OK, our fault for this misunderstanding. Cap, in this case, is short for capacitor. So while the plug connection may be unprotected, the breaker points get something. So there comes one more thing to check, which is the resistance of the secondary connection, between the spark plug connection and the engine frame. AND, for that matter, from the spark plug top to the engine body. If that reads less than an open circuit then the plug needs either cleaning or replacing. That is a simple diagnostic tool I learned many years ago. Checing spark plugs in place. Much easier and more accurate.

 

The magneto condenser (aka capacitor) is doing a similar job to a car one, so you could try a car one.

In English, the electrical/electronic world switched from Condenser to Capacitor early 20th century, the automotive terminology carried on using it.
Max.