Anyone here have their plugs fired off by a magneto?

Kinda curious as I always see any number of threads commenting on the merits of stock vs Pertronix and others – but never a mention of magnetos. 670236 came to me fitted with a Vertex mag. Brown bakelite color cap tells me it may be quite old. An owner previous to the previous owner fitted a discreet kill switch under the dash. Sometimes I’m tempted to quickly flick it off and on at speed but wonder if that’s inviting blowing a hole somewhere in the exhaust?

Very cool! I’ve not had one on anything except my childhood homemade car, which had a lawnmower engine. But I discovered something recently regarding magnetos in small engines. Back in the day (and with your Vertex) the magneto generated voltage to the coil without need for a battery, but breaker points and condenser were still required. But when I worked on a small engine, I noticed the magneto coil had a single wire that went to the spark plug. No points, no condenser. I read up on it, They are now “electronic.” When the magnet rotates past the coil, the induced voltage powers not ony the coil but also a circuit (potted within the unit) that interrupts the coil current with a transistor! I assume the modern magnetos do the same.

Yes. And if the fuel pump were mechanical, then there would be no need for a battery and generator to get me home.


As long as it was daylight🤔

Me. I grew up with dirt track, push-start open wheel race cars, invariably they were mag fired. I sent mine back to Joe Hunt for clean-up and check-up about 5 years ago. No issues. Still running on its original coil. One reason you don’t see many now is that Scintilla/Vertex/Ronco has not made a 6 cylinder version in many decades. And those 1950’s-60’s brown caps are now very rare. Most of the modern caps are black or a god-awful Ford blue. I have several 6 cylinder mags, not all of them Configured for a Jaguar. Ford 300 I6, Buick V6, etc. One or two probably pre-war. They are fairly modular. You can make a base and shaft to fit most engines if you have the top end.

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Greetings All/Christopher,

I have a magneto that came with a car I purchased. While the magneto works fine, it’s far too heavy and runs off the distributor drive.

Think of a generator mounted there on the drive. The gears take a beating and even the previous owner had made a bracing bracket to allow some of the weight to be supported by something other than the dizzy mount.

I also have a 60 AMP Lucas generator made for the Police. More eye candy for the shelf in the garage.

Your magneto, Lovell: is it a make different from the ones Mike has listed above? I’m curious now to know of any other magneto manufacturers who might have made these to fit a Jag. Lucas? Bosch?

Mike, I didn’t know how rare these are. It makes me want to start combing Ebay for spare parts as I have none for this mag. At the least, I’ll be searching for a spare cap, rotor, condenser – essentials like that to start. Possibly a spare unit. Wish I could have met the party who did some of these mods before the last owner as they seemed to have machinist/ fabricator skills. For instance, plug wires are routed through an aluminum shop-made bracket with an engine-turned finish:

The magneto itself sits higher than a distributor but still deep enough where it’s difficult to get a good picture:

I’ll want to start reading up on it’s maintenance too.

The strap retaining the timing mark plate on your Joe Hunt is a nice touch.

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Greetings All,

Mine is a Vertex.

I know the Joe Hunt name from him doing old BSA motorcycles.

The guy that made that wire separator was obviously handy but not too bright. Wire separators are also supposed to be wire INSULATORS. Phenolic is usually the choice. Aluminum conducts.

I also have a Mallory dual point distributor that someone fitted to an SS1, not sure there was any benefit?

I would disagree. The load on the gears is inconsequential, in my view. I would note that the same gears drive the oil pump, which is a MUCH greater load on the gears. The weight of the thing is supported by the block. I have never seen one of these mags, 4, 6 or 8 cylinder, damage the drive gears. Countless tens of thousands of these things were used in small Chevrolet V8 racing engines where the brass gear on the mag also turns the oil pump. I have never seen one fail. These things run for decades in industrial engines.

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Ditto: I was puzzled by the assertion, otherwise.

Good point. Bakelite/ phenolic would have been best. I’ll check for arc tracking in that area. Perhaps it could still be saved by drilling out the separator holes larger and fitting in black delrin/ acetal sleeves…

If anyone is aware of a 7 or 11 step program for those addicted to ignition systems, PM me. I’m asking for a friend. Clearly, I never met an ignition system I didn’t like.


I smell an episode of “Hoarders”…:joy:

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Most small aircraft still use magnetos because of their reliability. We restore pre world war cars which often had 2 ignition systems, one being a mag and the other being a standard coil and distributor. We have noticed that if we start a car using the coil and distributor then switch over to mag the engines always run smoother with the mag.