Ignition Wires

i get the crimp on wire ends with the threaded tip (for the plug connector end of the wire) from porsche, mercedes, or wurth. being it's sunday, i can't get the part #. all three suppliers have different numbers. i'll look tomorrow. remind me if necc. the 1K cap ends can be had thru worldpac. you just have to work with an intelligent sales person to find obscure stuff like this. that 18yo kid ain't gonna find it. resistors are used in plug wires to make the impulse work harder to force it's way to ground (at the plug), thereby making it stronger. there's some electrical theory that supports this.

Actually, the resistance is spark plug leads, rotors, and even the plugs themselves has nothing to do with the operation of an internal combustion engine, or the ignition system. It is there to increase the RC time constant of the electrical load circuit on the coil to lower the RFI frequency of the spark pulses. To stop making interference that can be heard in the high-dollar audio systems, in other words!!!

Super, you don't need additional resistance at the distributor end connectors, but if you want a 1K Ohm right-angle connector that will screw directly onto bulk 7 mm wire-cored cables, a Bosch 0.358.250.014 connector from BMW Bavaria's and 5,6,7-series cars of the '70s will work just fine.

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Warren Hall
1973 911S Targa

Quote:
resistors are used in plug wires to make the impulse work harder to force it's way to ground (at the plug), thereby making it stronger. There's some electrical theory that supports this.

There is *no* "electrical theory to support this".

The resistor in plug wires, connectors, and the plugs themselves is there to suppress electromagnetic interference. By changing the impedance of the circuit, and thereby the frequency of the RF radiation, things like radios and ECU's are protected from interference. The braided wire covering of OEM Porsche ignition wiring is also an attempt to control spurious RF by taking it to ground.




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Doug
'81 SC Coupe
Canada West Region PCA

[This message has been edited by Doug Zielke (edited 03-11-2001).]

Warren has infinite patience it seems. I am one of those unfortunate souls that would much rather "grok" something than just believe it. I care little about radio interference, except that I've heard of a danger of messing with demolition equipment, though this may be a wives tale. I have also heard of RFI damaging CDI systems.

Now, I wonder if this is a 'radiation' thing where the wires act like antannae, spitting a static signal, or if the problem is in the electrical circuit.

I am not reinstalling the stainless steel sock, which may be serving the purpose of grouding radiated energy. Okay, I think I'm just gonna hafta have some faith here. Thanks for your patience, Warren. I'm hoping John Walker will come up with a source for the screw ends. I'll be impressed and happy.

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'83 SC

Local Speed shop carries 7 7.5 and 8 mm
wire. Yellow Accel wire I believe the 7 & 8 mm are Solid core and can be purchased by the foot. Anyone use this wire before ??


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• Joe A.
• 84 911 Targa
• 75 914/6 3.0

well i guess i stand corrected on the resistor thing. i related to watching a high tension spark jump a gap, and as the gap was increased, the spark got fatter and nastier sounding. vw's had air gap connectors. is an air gap not resistance? not having grown up repairing radios, i may have some foggy areas when it comes to electronics. the bosch # for the 1K dist cap ends is 0356200006. the mercedes # for the crimp on plug connector ends is 000.159.1438. so far the local porsche guys are still looking for their #.

This is awesome. Thanks John Walker, I assume. I may be away from internet access after business today, but I'll be driving though Metropolis tomorrow afternoon, and so can pick up parts. I'm very excited. In a good way.

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'83 SC

The Porsche dealership in Tacoma does not show the screw connectors as available separately. The Mercedes dealership does have these connectors though, and my favorite parts guy here in town was able to use the part numbers to order what I need. I should know by 5:00 tinight. I am hopeful. Will keep you posted, but I'll likely be away from Internet 'til tomorrow sometime.

Hey, a very appreciative "thank you" goes to John Walker's Workshop.

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'83 SC