Author Topic: Replacement spark plug leads - any impact from electronic ignition?  (Read 3127 times)

w113abudhabi

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  • United Kingdom, England, Wigston
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  • 1970 280SL Papyrus White / Red
Hi

I have a 1970 280SL that appears to have been converted to electronic ignition. Does this have any impact on the choice of replacement spark plug leads. I was intending to purchase these:http://www.authenticclassics.com/Mercedes-280SL-Ignition-Spark-Plug-Wire-se-p/auth-004612.htm

Thanks

Pierre

Shvegel

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The short answer is from an electrical standpoint it shouldn't matter. Any radio noise suppression wire set(pretty much all of them these days) will work.

The longer answer is there are basically 2 types of resistive ignition leads available.  The first is a carbon core wire which is comprised of a core of glass or kevlar fibers impregnated with carbon which is surrounded by insulation. These are usually inexpensive wires but they have several disadvantages the first being that the length of wire effects the resistance of the wire so a short lead will have less resistance than a longer lead. That means that the spark plug will have a harder time firing on a longer lead than a shorter one(higher firing voltage) and as the firing voltage increases the chance that the spark is going to try and find a way through the insulation of the wires rather than across the spark plug gap.  Rough handling and for that matter just use over time tends to cause the cores to get damaged which can also cause misfiring.  

The second major type of wire consists of a solid metal wire usually copper surrounded by insulation with a wire end that contains a resistor which is usually around 1,000 ohms.  These wires should present the same resistance regardless of length which means similar firing voltages, less missfires and by their nature they should last longer than the carbon cored wires.

The wires you selected appear to be Bosch solid core wires.  A good choice.  

Bosch is also a worldwide parts company.  You may be able to source them locally.
« Last Edit: March 11, 2015, 00:38:25 by Shvegel »