which plug wires for my mag?

[Peter]

hello,
can somebody tell me if regular plug wires are long enough to use with a magneto?
or do you have to make them yourself?
thanks!

[JS]

I use the regular Bosch ones with good results.

[Peter]

Thanks Johnny!

[dragvw2180]

 If the engine is used for racing only I would use a non resistor type like this,   http://www.magnecor.com/magnecor1/main.htm    . It was what I used last century (LOL) when I ran a mag. This is not a good choice for the street though , any onboard electronics will be effected. Mike McCarthy

[Peter]

Thanks,
Its a street car,
but when i have the mag, no electronics will be on board anymore

[Peter]

I ve got some Taylor 'spiro' ? wires...
are those good as well?
or do they really need to be copper core?

[hotrodsurplus]

You need a non-resistor wire. A wire with any kind of resistance defeats the purpose of a magneto. A magneto delivers a very high-energy spark. Resistor wires diminish that energy.

http://www.donzig.com/whatwires.html

Don't forget that you also need non-resistor ends. I believe the black ends lack resistance and the brick-red ones have resistance but I could be wrong. 

[Peter]

Thanks for that,
the taylor wires are resistorless, but not copper....

these are the ones i have:

http://www.cbperformance.com/ProductDetails.asp?ProductCode=2097

OK to use them or not?

[JS]

You need a non-resistor wire. A wire with any kind of resistance defeats the purpose of a magneto. A magneto delivers a very high-energy spark. Resistor wires diminish that energy.

http://www.donzig.com/whatwires.html

Don't forget that you also need non-resistor ends. I believe the black ends lack resistance and the brick-red ones have resistance but I could be wrong. 

Just out of curiosity, when you say that one "needs" non-resistor wires, what does that mean?

[hotrodsurplus]

Thanks for that,
the taylor wires are resistorless, but not copper....

these are the ones i have:

http://www.cbperformance.com/ProductDetails.asp?ProductCode=2097

OK to use them or not?

I don't think that the conductor material matters so long as it's a quality material. For example the ones Joe Hunt sells are stainless and stainless is a terrible conductor compared to copper but they work just fine. Hunt doesn't sell junk. I would say those CB wires will do the trick.

[hotrodsurplus]

Just out of curiosity, when you say that one "needs" non-resistor wires, what does that mean?

The resistance in a conventional high-tension conductor suppresses the EMF that interferes with electrical devices like radios. It doesn't apply here but that EMF also destroys the electronic components in conventional ignition components which is why you should not use non-suppressed wires in a car with electronic ignition components.

That resistance also diminishes some of the spark energy. The sole purpose of a magneto in a racecar is to produce enough energy at sufficient pressure to maintain a spark under very high-speed and high-turbulence conditions. So the suppression wires defeat the purpose of a magneto.

Read the material in the Don Zig link for more information.

[JS]

Just out of curiosity, when you say that one "needs" non-resistor wires, what does that mean?

The resistance in a conventional high-tension conductor suppresses the EMF that interferes with electrical devices like radios. It doesn't apply here but that EMF also destroys the electronic components in conventional ignition components which is why you should not use non-suppressed wires in a car with electronic ignition components.

That resistance also diminishes some of the spark energy. The sole purpose of a magneto in a racecar is to produce enough energy at sufficient pressure to maintain a spark under very high-speed and high-turbulence conditions. So the suppression wires defeat the purpose of a magneto.

Read the material in the Don Zig link for more information.

Ok, I see your point. It seems to perform pretty good with stock wires too though.

[hotrodsurplus]

Ok, I see your point. It seems to perform pretty good with stock wires too though.

Yes, a mag will work with stock wires. It just may not develop any more energy than a conventional inductive ignition would in a similar application. Understand that at very slow speeds (engine cranking) a magneto does not generate very much energy and that suppression wires/ends may cause problems in those situations.

I should clarify my statement: to get the full benefit of a magneto you must run non-suppression wires and wire ends.

[TexasTom]

Wires do make a difference!
Depending on the application ...
TxT

[Peter]

Thanks a lot!
I am going to try the cb wires today

[dragvw2180]

 I mean no disrespect to anyone and I respect everyones opinions , having said that  The CB wires you posted a link to are NOT a good choice . I would use something with a metal conductor . The mag will throw out a hot spark but does not like any resistance or too large of a gap on the spark plugs. If the plug gap is too large it will not overcome the resistance to spark the plugs. A friend of mine who owns a motorcycle shop was rebuilding an old Harley with a Joe Hunt mag on it . It would not start and he was pulling his hair out, even sent the mag back to have it checked,  all that was wrong was the plug gap was too large . I had him regap the plugs from .035 to .018 and it fired right up along with unshrouding the tip of the plug . I hand filed the ground electrode of the plug to a > and had the tip of it dead center on the center electrode .  The spark plugs I used back in the day  were NGK Gold Palladium also. I know everyone who posts here on the internet means well and no one intends to give bad advice but my advice to you is listen to everyone , ask who has actually done what you are asking about , then research everything yourself . Mike McCarthy

[hotrodsurplus]

my advice to you is listen to everyone , ask who has actually done what you are asking about , then research everything yourself .

Probably the smartest advice on the forum.

That post also underscores the importance of eliminating suppression-type components. That also applies to the spark plugs. I don't know if the crossover plug Bosch supplies is a suppressor plug bug the old W*AC series was a non-suppressed plug and at least theoretically correct for a mag application. The presence of an R in a plug number usually designates resistance (the NGK BR5HS for example).

The tight-gap observation partly bears testimony to a mag's inability to generate lots of energy at slow speeds (like cranking). Most of my mag experience is from blown Chevrolets and Chryslers. We found that we could get it to light with as much as .020" but if the engine didn't catch almost immediately then it would never start. The battery voltage would drop and the engine would crank just slow enough to prevent the mag from making sufficient power. They'd light reliably once we got the gap down to .016". Your mileage may vary.

We ran copper-core wires on those ignitions.

It also pays to make sure that the poles in your magneto are sufficiently charged. Poor magnetic charge will hinder a mag's output big time. Aircraft run magnetos and aircraft shops are almost always close to private airfields. If you break down the mag yourself those shops will re-magnetize the poles for way less cost and time than automotive mag shops will.

You can get the tools to work on a magneto inexpensively from Speedway Motors. You'll need a timer (buzz box) to reset it but they're not expensive.

Become the expert on magnetos. There's a ton of information out there but not a lot of it floating around in the VW world.

[Peter]

Thanks guys...
i started the motor with the bosch wires and it idled...
i locked the advance and of course the starter didnt like it...
i didnt check the spark plug gap though..
a job for tomorrow maybe

[hotrodsurplus]

i locked the advance and of course the starter didnt like it...

Install a momentary switch on the dash that grounds the mag or energizes the relay that grounds the mag. Push the switch as you start cranking the engine. Once the engine starts spinning then release the switch. The momentum will usually push the engine through a compression cycle and if all is well it'll start like right now.

Just remember that the Bosch wires are suppression wires and will diminish the spark energy. They also have suppression ends.

By the way, you don't need to spend a lot of money on solid-core wires. Bosch still makes solid-core wires with non-resistor ends and they cost a lot less than the resistor-type Bosch wires. And bonus of bonuses: they have the angle ends at the cap that everybody seems to love.

http://www.thesamba.com/vw/classifieds/detail.php?id=736220

If you're looking to maintain a vintage vibe you can still get the conductor that everyone used through the '70s. It's Packard 440 and it's available in reproduction. You order it by the foot and cut it for the application. The most economical way to do it is to buy the cheapo Bosch kit and replace the conductor with the Packard stuff. It's not very expensive either--less than $2 a foot. It's cool lookin' stuff.

[JS]

Thanks guys...
i started the motor with the bosch wires and it idled...
i locked the advance and of course the starter didnt like it...
i didnt check the spark plug gap though..
a job for tomorrow maybe

Why would you want to lock out the advance?

[dragvw2180]

 If it is a turbo or supercharged application I would lock it out but  with a N/A setup I would run my rpm's up until the mag or distributor would quit advancing then advance the timing to my desired setting , say 32 degrees total advance. On most engines I did this way it would start great and perform well. I did do the cut off switch on my mag on some high compression engines and that was a good suggestion. Did any of the old timers ever have a problem with the brass gears wearing out quickly when running a mag ? Mike McCarthy

[hotrodsurplus]

Why would you want to lock out the advance?

The typical engine that can benefit from a mag seldom operates at slower speed ranges where it would incur detonation. Once a drag car launches its engine may never operate at anything slower than like 5,000rpm. If you think about it, the advance in a conventional ignition is usually all in by 3,000 to 3,500rpm.

Magneto advance mechanisms are crude at best. They use a series of brass plates to govern advance so to tune them you have to have the correct plates on hand. Tuning the advance mechanism also requires disassembling the magneto which involves a fair amount of work and inevitably re-timing the points and so on. Because of the operating range these engines experience it's usually not worth the hassle.

The typical engine that needs a mag also runs a wicked-long-duration camshaft. Closing the intake valve really late prevents the cylinders from developing very much pressure at slower engine speeds. Of course that changes with speed. Fluids operate under the same inertia laws as everything else and at one point the column of air flowing down the manifold achieves enough velocity to overcome the reversion created by the piston pushing some of the intake charge back out of the intake valve. The combustion efficiency is really poor at those slower speeds so lighting the candle really early gives the cylinder a better opportunity to achieve reasonable combustion.

Your engine laboring to crank indicates that it achieves pretty good pressure at slower speeds. And that indicates that the cam doesn't have a lot of timing. Mike's observation about running a bit of advance with forced-induction engines addresses that issue. Forced-induction engines don't need to run a lot of timing to make big power therefore they develop a lot of cranking pressure. Most magneto advance mechanisms don't advance like conventional advance mechanisms. They exist so the engine can fire at a reasonable advance (say 12 degrees) and basically advance fully once the engine reaches idle speed. The same would apply to a NA engine with moderate cam timing and a fair bit of compression.

I too want to hear first-hand information about cam-gear wear when running a mag. I've heard second-hand accounts about the terrible things that a magneto does to the brass gear but I have my doubts. We had to use a brass gear on one Chevy we built because we ran a billet cam. That ran fine and bear in mind that a Chevy also drives the oil pump from a tang at the bottom of the distributor/magneto drive. A pump imposes a ton of resistance and the Chevy pumps are quite big. We also ran straight 40-weight oil in most of those engines. I know the design differs but the surface-contact area and the surface speeds can't be all that different and the VW doesn't drive the oil pump from the distributor anyway. I know that poor-quality brass gears will fail prematurely but I wonder if there's a failure issue with running a mag on a good gear.

[Peter]

Well, I locked the mag, because I didnt understand tha advance mechanism at the time when i first installed it...
The timing was very erratic... So I thought I d lock it... i just need to drive carefully at lower speeds and listen if it detonates or not... don't know yet..
but most of the time I drive above 3000 rpm anyway, so I think it ll be OK. just dont floor it in 4th uphill
but Actually the coil was broken, so that was maybe why the timing was so erratic...
Now the mag has a new coil and capacitor..
I think I am in luck: the bosch wires that i installed now are the cheapo ones with 90 degree ends black plug tips as well, so no resistance....
the engine has an fk8 , so you re maybe right... not enough overlap? but that ll change in the future for sure was thinking fk89 or something.
And i did use the switch as well and started it like you say...
Honestly i didnt set the timing yet, just wanted to see if it would start and run 
thats something for today... thanks for the link of the packard wires ! that would look cool.

Peter

[Peter]

got a cool window sticker too

 

[Peter]

This is maybe a dumb question,
but i can use a strobe light to set the timing, right?
or do i need to do the cigarette paper trick ?
Please bear with me, i am still learning about these things

[dragvw2180]

Cool looking engine, brings back some memories. One thing I would suggest is to look or make a clamp setup for the mag . The one I had made came off the fuel pump studs and clamped around the maghalf way up  to keep it from moving . I am sorry that I do not have any pics . Mike McCarthy

[Peter]

Yes Yes! I will make a clamp!
Its an autolinea case, so maybe stronger... but i will do it anyway!

thanks again for all the help!!!

[JS]

As for running a locked out system I have read your answers but still don´t see why you lock it out. The only thing I can see it do is making the engine harder to start. I know absolutely nothing about turbo engines, so you got me there.
I do believe it´s worth making adjustments to make your engine user friendly.

As for cam selection I have tried the mag on FK8, FK46 and two different custom grinds from JPM. First with the advance curve from an industrial engine(I think 11,5@1850rpm), then shipped it to Joe Hunt to have it rebuilt and the magnets charged. I had the curve set like a 009(24@3000rpm).

I didn´t know there was a lot of different advance systems in VW magnetos. Most of the ones I have seen have been Vertex Scintillas, only with different badges(Scintilla, Hunt, Zig, VW/Audi). But I obviously never opened them so maybe you are right about that Chris.
As for the low advance set in many mags, could this be because they were made for either an industrial or aircraft engine which operate at a constant rpm? Just a thought.

Peter, I don´t think erratic timing is related to the mag being locked or not.
I set my timing with a cheapo timing light and an external battery. I used to set it static with a buzz box or multimeter, but I have much better experience with a timing light and setting the dynamic timing. When I ran a FK8 i had no problems starting the engine without a separate button for the mag. I made a clamp with the OG clamp from a 30hp industrial engine and a support that uses a bolt on the generator stand.

All these experiences are first hand. But they are only mine, not the truth.



PS. The observations about plug wires and spark plug gap are interesting. I always ran stock Bosch carbon wires with resistor. The engine fires right up every time. Good spark if you test the mag out of the car by hand. I tried once to change the gap from standard 0,028" to 0,018 and it made no noticeable difference. I run NGK D7EA plugs.

Has anyone done back to back testing on this and measured spark travel?

[Peter]

Johnny,
Honestly i locked it for the simplicity and lack of knowledge of how much the advance worked
I now have set the timing to about 30 degrees, and it starts fine without using the switch...
I just advanced it way too much yesterday just by sight...
I checked that this morning with my timing light and it was like 40-50 degrees...
no wonder the starter didnt like it
I did a testrun today and no signs of pinging... at least i didnt hear anything strange..
next is check the plugs to see if something is wrong or not...

[hotrodsurplus]

This is maybe a dumb question,
but i can use a strobe light to set the timing, right?
or do i need to do the cigarette paper trick ?
Please bear with me, i am still learning about these things

The only dumb question is the one you don't ask. Yes, you can use a conventional timing light to set the timing. A magneto produces the same inductive spark as any other non-CD ignition system. The difference is that it's a lot hotter.

As Mike said the mag benefits big time from a good clamp. In fact Volkswagen specified a larger mounting boss and made a bigger clamp to hold it. Note how much bigger the mounting boss/clamp is on the industrial mag on the right. The one on the left uses a clamp with the VW diameter; however, the clamp area is a lot thicker (unfortunately I don't have the clamp but that shouldn't be hard to make).

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