Low Resistance Electrical Parts

[Snoww_]

We've gotten our 1955cc motor up and running after a lot of work on the rebuild and have a couple hundred miles on it. Now we're into the fine tuning stages. Dual Weber 44s have been jetted and rejetted but it seems like we're missing something with the spark.

It's pretty weak. We've got a 3ohm coil and a pertronix flamethrower III distributor. But we found that we had a rotor with ~1000ohm resistance, bridging that with a jumper wire made a noticeable difference. Feels like we picked up a good bit of power.

What are our options to drop the resistance of the cap, rotor, plug wires, plugs?

We've kept the same electrical hardware after the distributor because it's always worked but we want to make some improvements.

Any recommendations?
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1991 Tiico Vanagon Carat
1961 Baja Bug

[vwracerdave]

Pertronix flamethrower III distributor uses a .32 OHM flamethrower III coil.

Click on the link the download the instructions.

https://pertronixbrands.com/products/pertronix-d71...7222965284
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2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK

[RCP Phx]

Yep, I bought the Flamethrower III ignition and the Flamethrower III coil.

[Snoww_]

Wow, I can't believe I missed that.

I'll double check the distributor and coil but you just solved a big mystery for me.

Thanks!
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1991 Tiico Vanagon Carat
1961 Baja Bug

[[email protected]]

Taylor Thundervolt 8.2mm wires have 40 ohms per foot that may help depending on what your current wires are. FAST’s PS60 coil has 0.400 ohms resistance, but would produce more amperage than the Flamethrower 3 coil if the PS60 is compatible with the distributor. Non resistor spark plugs are becoming more difficult to find depending on application, but that would help as well.

[W1K1]

if you want a much stronger spark, I would recommend a Winterburn CDI
http://www.capacitordischargeignition.com/
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http://www.thesamba.com/vw/archives/manuals/jim_martin_engine_build.php

1973 super
1965 squareback 1500E
1971 bay window westy- subi swap

[Dan Ruddock]

[Floating VW]

[Snoww_]

Thanks for all the advice. Turns out we do have the correct Flamethrower coil. I went ahead and ordered new Taylor Thundervolt plug wires, a non resistor rotor, new cap, and non resistor plugs. I'll see how this goes and if that's not enough I'll certainly move on to the Winterburn CDI.
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1991 Tiico Vanagon Carat
1961 Baja Bug

[EVfun]

Resistance on the secondary side is very different than resistance on the primary side. On the primary (for conventional Kettering ignition) the current may hit 4 amps peak. On the secondary side you might hit 20 milliamps (0.020 amps.)

Voltage equals the current times the resistance. If you put a 1000 ohm resistor on the primary side the you cannot pass enough current to make a decent spark. A 1000 ohm resistor in the rotor on the secondary side and might drop around 200 volts. You have 10,000 volts or more (hopefully more) available. It is not significant.

On the old Bugs it was normal to have a 1000 ohm resistor built into the rotor and another 1000 ohms built into each of those resistor ends that push onto the threaded end of the spark plug. Even on a 6 volt car that wasn't enough of a drop to be a concern. I'm only aware of one situation where you need to remove the resistor rotor. If you have a capacitive discharge ignition they pass multiple strong sparks per ignition event -- that may cause a resistor rotor to overheat from excess current and fail.

Traditionally resistance on the secondary side was used to suppress the radio noise from the ignition system. Resistor spark plug wires may another 5000 ohms per foot, resistor spark plugs may add as much as 3000 ohms on top of that (and it is getting harder to find copper core plugs.) The old Bug made due with a resistor rotor and resistor wire ends. For the most part, that system works pretty good on a performance engine too, at least now that we don't worry so much about AM radio.
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