braided plug wires

[g sturgill]

I need to replace the spark plug wires on my 73.5 with CDI. Parts of the wiring are oil soaked, (under the air box), and some of the stainless steel braiding is frayed in places. The question is do I need to replace the wires with shielding, or can I go with a less expensive set of cables? What are the consequences?

Thanks, g

[yelcab1]

no shielding is needed with Magnacor wires

[Walt Fricke]

The metal braid over the plug wires was Porsche's attempt to solve the problem of backfires blowing up the CIS airbox. I didn't think the braid came with the car as early as the 73.5, but perhaps it did.

In any event, it appears that plug wires played no role in backfires. So they serve no really useful purpose. Though they do look sort of purposeful and thus cool. Problem is, they are a lot more expensive than plain plug wires.

Porsche pretty much solved the backfire issue with the SC, where (at some point, anyway) they added steel channels inside the airbox which directed the fuel from the cold start injector (which seems to have been the culprit) to each of the six separate intakes (exits from the airbox).

[gsjohnson]

Originally Posted by yelcab1

no shielding is needed with Magnacor wires

+1 on the Magnacors

[jmohn]

The braided shielding is unnecessary. Just buy quality cables; others have had good experiences with Magnacore, Clewett (sp), etc.

Personally, when I replaced the cables on my SC, I bought the Beru cables for an earlier car (69-73 IIRC), without the shielding, from our host, they have performed very well.

Jerry M
78' SC

[bpu699]

Could off brand plug wires cause poor radio reception? Just curious. My 930 radio sounds great until the car warms up, then reception goes to crap. The PO replaced the plug wires, but I don't know the brand...

[Bill Verburg]

Originally Posted by bpu699

Could off brand plug wires cause poor radio reception? Just curious. My 930 radio sounds great until the car warms up, then reception goes to crap. The PO replaced the plug wires, but I don't know the brand...

It's possible, RF is emitted from any conductor w/ ac flowing through it. The spark current qualifies. RF is is handled 2 ways one shield the conductor or use a resistance in line to move the RF out of the range that will affect the vehicle electronics.

you can use unshielded steel or copper core conductors as long as resistor plugs or resistor connectors are used

Magnacor and others use a coiled shield wrapped around the conductor to contain the RF inside the wire that was the purpose of the braiding.

[wwest]

The braid will act as a capacitor and slow the rising edge of the spark pulse, detrimental to good sparks. Straight wire core, non-resistive, HV wiring will interfer with radios, TVs, etc.

[balleta]

I made a new set of cables out of an ACCEL V8 set. Using the spark plug side Beru terminals from the old set. Just screw them off and attach to the new cables. No problems and inexpensive.

[flatsixjunky]

Originally Posted by balleta

I made a new set of cables out of an ACCEL V8 set. Using the spark plug side Beru terminals from the old set. Just screw them off and attach to the new cables. No problems and inexpensive.

PM sent.

[James Brown]

Yeah, you can get the M3 terminals and crimp on your own wires and diy. No need to buy expensive sets of custom made wires. There are some great threads on this subject. I used a set off a Ford Crown vic that fit right on the plugs, $10 bucks from a recycle yard.

[Bill Verburg]

Originally Posted by balleta

I made a new set of cables out of an ACCEL V8 set. Using the spark plug side Beru terminals from the old set. Just screw them off and attach to the new cables. No problems and inexpensive.

The Beru terminals are the key, they have an internal resistor in them. it would be cheaper to buy a roll of wire than a set precut and pre-assembled for another car. Although the spools do seem to be harder to find these days

The 2 most popular cores are solid stainless steel and copper and tin coated copper. I prefer ss for it's corrosion resistance closely followed by tin coated copper.

the Magnecores are a really good alternative