magneto questions

[65bug]

Hey guys,
    Can you school me on a magneto. I do not know too much about them.

1. What are the benefits of a mag over a coil and distributor?
2. Any one better then the other? A preferred model or make for a VW?
3. Are they still being built new?
4. How is the timing set with one? The same was as a distributor?

      Thanks!   

[Fastbrit]

1. Big fat spark; simplicity; self-sufficient (doesn't need a battery to work); looks WAY cool!
2. Vertex – or named variations thereof (Scintilla; Don Zig; Joe Hunt etc)
3. Yes
4. Yes – inductive timing lights still work

Remember: just about every light aircraft runs a magneto (or rather, two of them). Never seen an aircraft with a Brazilian 009...

[65bug]

Fastbrit,
      Thanks for the info. So no hot wire to the magneto at all? What about HP ratings? More with a magneto?


Thanks!

[65bug]

but they use points and condenser? Wow! Can they be converted over to electronic ignition?

[TexasTom]

The only wire you'll need is for your tach signal and a 'KILL' wire.

Will start dang near anything under the worst of conditions ...
Have you ever forgotten' to take the stack covers off the 48s before you jump in to go for a ride?  Crank it for 5-6 seconds to no avail???
Not a problem ... peel those covers off and its Magneto to the rescue! LMAO

Try it, you'll like it!
TxT

[Jon]

Is there any truth to the "fact" that the magneto produces four sparks in one rotation. And in doing so are producing sparks even at a high rpm where a coil might not keep up? (short time to load up)
Or is this just mumbo jumbo as I have begun to suspect. 

[TexasTom]

Is there any truth to the "fact" that the magneto produces four sparks in one rotation. And in doing so are producing sparks even at a high rpm where a coil might not keep up? (short time to load up)
Or is this just mumbo jumbo as I have begun to suspect. 

It turns at the same speed as any distributor ... it's not producing 'extra' sparks if that's what you mean.
Also, as engine speed increases, so does the power generated to support the higher demand of the ignition.
Is that what you mean/make sense?
TxT

[Nostalgiavw67]

Cool tread, I've already have answer to question I did'nt even post!

Thanks!

One more, my magneto need to be redone, who can do that? And where can I get some spare parts?

[Pas]

Hope you don't mind me jumping in with some other questions.

Does anyone know where you can find wiring diagrams/info for a magneto. With only 2 wires I am guessing it wil be a pretty simple job.

Do you need a specific magneto compatible tachometer or can any be used?  

Thanks

[Rocket Ron]

Hope you don't mind me jumping in with some other questions.

Does anyone know where I can find wiring diagrams/info for a magneto. With only 2 wires I am guessing it wil be pretty simple job.

Do you need a specific magneto compatible tachometer or can any be used?  

Thanks

here you go dug this up a few days ago 

http://www.jegs.com/InstallationInstructions/100/105/105-9118.pdf

you will either need a magneto compatible tachometer or a signal converter like this

http://www.jegs.com/i/Auto-Meter/105/9118/10002/-1?parentProductId=751846

[marc1951]

Only 1 wire to mag and when grounded, it stops the mag from generating spark (killing motor).
Some tachs, like my early VDO work just fine, just hook it to the "kill" wire. Others you need the converter mentioned.
You can time the motor with timing light as mentioned once it's running but you can't use a 12v bulb or multimeter to set static timing (10 degrees typically). If you connected a continuity meter to the mag terminal and ground, it would appear the points were grounded no matter where you rotate the mag.You have to use a "buzz box" that detects the inductance in the mags coils. You can buy one for $30-$75 (the buzz box).
If you decide to run a mag, I strongly suggest you buy (JayCee) or build a brace for it as the base will crack from the vibration of all that extra weight.
I find the spark weaker when starting the car and getting stronger as the RPM go up, I run the spark plug gap at .018 to.020 (.028 is normal)
If you buy a used one and it's been around for a long time, the magnets can lose their strength and diminish the spark. You can have the magnets "recharged" by someone who services mags, like Joe Hunt.
I've never seen a horse power increase from a mag and in fact, the mag uses a small amount of HP to run it. You gain a better spark at higher RPMs where a distributor may fall short.  The modern electronic ignition systems kick ass and I think are superior to a mag for a street car.....HOWEVER, a Joe Hunt magneto sitting between a pair of 48 ida webers is pure sex.

Hope this helps

Marc Buehler

[Fastbrit]

Forget spending money on a 'buzz box'. Put a thin piece of paper (cigarette paper is perfect) between the points contacts. With the engine off, turn the engine over by hand until the pulley says 10° BTDC, then rotate the magneto anti-clockwise just enough so you can pull the cigarette paper out from the contacts. Tighten the mag clamp, refit the cap and leads and start the engine. Now use the timing light to set timing accurately as normal. This is how I have done it for the last 30 years. Saves spending $30–$75!

[andy M.]

tight arse

[65bug]

I knew they would cost you HP! Thats a bummer. They seem VERY cool. But my Mallory is bitchen and uses very little if any power to spin it. That magneto uses more power. Not yet for me.............

[Fastbrit]

I knew they would cost you HP! Thats a bummer. They seem VERY cool. But my Mallory is bitchen and uses very little if any power to spin it. That magneto uses more power. Not yet for me.............

Do you seriously think you'll notice any difference unless you run a computerised dyno, maybe? As for real world fugures, I believe Roger Crawford has carried out tests and the results were pretty favourable... In many situations, the fatter spark of the magneto will bail you out of other problems caused by jetting etc.

Sometimes you should go with your heart...

[65bug]

Fastbrit,
      If I come across a good deal I may buy one. But right now no big hurry. I am sure they do not use alot of power. But it all adds up. We'll see. The classic is this weekend

[TexasTom]

I'm relatively certain the power 'loss' to the use of a magneto is inconsequential (certainly in a street driven ACVW) else why would it have been the ignition of choice (and still is in some cases) for so long in the past?
The obvious benefits of new technology mainly lies, in my opinion, in the ability to manipulate.
I'm not saying either is better, just another choice available.
TxT

[Bryan67]

And if you pick one up at a swap meet be careful! Don`t spin it or you  will light up your world.

[65bug]

    Hey, if you guys have any pics of yours please post em! I would love to see your magneto's!!!!!!



Thanks!

[javabug]

Best. Magneto. Story. Ever.
http://cal-look.no/lounge/index.php/topic,5983.0.html

[65bug]

Well, he was comparing a piece of crap(possibly even defective) distributor to a magneto. Thats a pretty BIG difference. My Unilite puts off one big spark too. Great story!

[Type1/DVK]

it's static timing 31-33degr. right? also @ idle?

[Fastbrit]

it's static timing 31-33degr. right? also @ idle?

Only if locked out...

[JS]

Torben Alstrup told me that the theory about the mag producing bigger sparks at higher rpm´s if just that - a theory.
On a four cylinder engine it uses a quarter turn to deliver a spark, and if that time is longer og shorter it will produce the same spark.
If this is correct I have no idea, but I certainly don´t think my car is harder to start now that I run one.

[besserwisser]

I have bought every magneto in Sweden I can get my hands on. I fly to San Fransisco every year and I take the drive up to sacramento and leave them to Joe Hunt. He reworks them and change them to a 009 curve. When everything is done the magneto works out cheaper than the MSD mumbo jumbo stuff that can break down because some 50cent piece couldnt take the current and your racing weekend is over. It has happend to me so from now on its magnetos. After all they used only magnetos on airplanes during ww2 so if you trust them up in the air I will use them on the ground. besides what beats the look of a fat magneto on a race engine? With some luck I will drive to Bad Camberg with a 1835 TDE single port motor with a fat magneto. 6volt of course.Se you at BBT on the thursday before Bad Camber

[Fastbrit]

My 1951 Beetle with the Okrasa motor had a magneto – I happily drove it all over France and Germany and back to the UK without any worries. Cool, reliable and cool, as well as being reliable – and cool.

[TexasTom]

And then there's the COOL factor ... 

[Speed-Randy]

COOL!!!

[TexasTom]

Torben Alstrup told me that the theory about the mag producing bigger sparks at higher rpm´s if just that - a theory.
On a four cylinder engine it uses a quarter turn to deliver a spark, and if that time is longer og shorter it will produce the same spark.
If this is correct I have no idea, but I certainly don´t think my car is harder to start now that I run one.

This is my theory, which is backed by aircraft technology, though old ... Be that as it may.
A magneto is basically a generator that produces power for the ignition built into it, this is widely known.
Generators do not reach maximum rated power until an optimum rpm is obtained and so the power delivered to the ignition WILL increase with rpm due to the fact that the power is generated by the coil passing through the magnetic field at rpm ... ever notice how the dash lights increase in intensity when you rev it at night?
If the power/current is increased to the ignition source the Spark can and Will Intensify.
As to the aircraft technology ... most any aircraft is equipped with two magnetos, not only as a back-up but also for power increase through increased mixtrue burn ... trust me & try turning one mag off while in flight ... BIG difference!
Aircraft are equipped with an impulse coupler that during start-up will increase the velocity on a controlled intermittance on the magneto to fire the plugs ... the engines are simply not turning fast enough by the starter to fire the engine, not enough rpm = not enough spark intensity available @ low rpm ... it's a jerking motion that flicks (if you will) the magneto to produce the spark. You can hear it if you listen closely while firing an aircraft engine ... no impulse coupler no flight!
Look at it this way ... even an MSD needs X amount of voltage to work properly & there's a reason many race teams run 16V batteries, not just to start the dang thing ... ! LOL
TxT

[Jim Ratto]

Well, he was comparing a piece of crap(possibly even defective) distributor to a magneto. Thats a pretty BIG difference. My Unilite puts off one big spark too. Great story!

distributor was not defective or a piece of crap.

problem(s) was a few things the mag "masked": 1. second year of ownership of 48IDAs on my daily driver consequently, the blind was leading the deaf as far as jetting goes (in retrospect, we were drowing that motor w/ way too much fuel) 2. Cam was slowly going away, yep mag masked that too. 3. It was a "street intended" motor that really didn't belong on the street, it had drag race parts but not drag race compression nor a guy that knew what the hell he was doing building it/tuning it/driving it/maintaining it.
my smaller motor running 010 with points in my car now would eat that Super Flow motor I had for lunch. All about the tuning which comes from experience.
A mag will make your carb tuning less "specific" so you can err outside the motor's comfort zone. I still have the 009 and Bosch red coil that were in that motor, 20 years later and they are my backups.
I just shelved an MSD distributor because it held my car back. Same with a good friend of mine in DKP