Magneto Help

Hi There,
I have installed a Vertex Magneto and the engine won't start. This is a little frustrating.... new plugs, gaped to the required amount, set 7.5deg BTDC, new leads, Now when I crank it over there is such a small spark. Would it produce a large spark if cranked quicker? Engine runs fine as I have swapped back to Dist and coil to run next week.
BTW thanks Dave B for the Cap and rotor, he must have way more stuff hiding round the house...Ha ha..!
Has anyone run a Magneto???

Frosty, I would say the Mag needs a rebuild and a new coil pack, sounds like it is not making enough spark when being cranked by the started to fire the engine up, Mine did the same thing. Hardimans in Sydney rebuild them they are not cheap to do.

I rebuilt mine ran it for a while then switched to an electronic ignition. Mags are a thing of the past, an electrinic ignition system works much better, just doesn't look as cool. 😎

From what I've read. (and experience with lawn mower lol)
Magnetos are ideal for stand alone ignitions application such as light vw engine aircraft, those drag car that doesn't have a generator and little battery to run the gauges or a lawn mower
magneto spark would be weaker than coil and points but it probably make bigger spark at higher revs.
(correct me on this)

I would try reduce the gap on the plugs before having the mag rebuilt
(worked on my lawn mower hah)

.018 thou plug gap

I will make the gap smaller, it says 0.026-0.045 thou?. I'm also going to spin it with the Drill ( slowly about 2500 rpm) and see if the spark is greater.
(I can feel a big shock coming)

I had one of those Vertex magnetos on my Beetle race car about 30 years ago. Hardimans set it up for me (very expensive) and it worked well.
There are a couple of reasons why I would not do that now, mainly there are some very good ignition systems available now. Also the mag. is very heavy - not a good thing right up the back of the car from a cornering perspective. There is a way of storing magnetos so that the magnets don't 'go off' -its' called the 'keeper position' - perhaps Hardimans can tell you how to do that.

Cheers, Greg

Hi

They are old hat compared to what can be bought now, but they do look cool.

One quirk that they do have, is that they are shut off by earthing out the unit, if your unlucky enough to have a stuck throttle at high rpm the magneto can over power the earth, not nice.

Steve

1303Steve wrote:Hi

They are old hat compared to what can be bought now, but they do look cool.

One quirk that they do have, is that they are shut off by earthing out the unit, if your unlucky enough to have a stuck throttle at high rpm the magneto can over power the earth, not nice.

Steve

That is exactly what happened to me on my first test drive with a freshly rebuilt mag, fitted it but didn't hook up the earth wire so I could switch the engine off.

I went out along the road just out of town for a quick spin, turned around and gave it the berrys 1st, 2nd, 3rd and 4th gear, pulling around 90 mph plus, went to back off over a slight rise heading into the 60 zone and the accelerator got stuck with carbs at WOT, turned the ignition off and of cause that did nothing, accelerator was jammed under the carpet, didn't want to declutch and destroy the engine, could have turned the fuel pump off and waited for the carbs to run out of fuel but was running out of safe road fast, the brakes didn't do a thing so I ended up leaning down and pulling the pedal up with my hand, was a scarey few seconds. This was with my 2165 engine that made 143hp at the wheels, so it was moving.