What’s the current consensus regarding the correct spark plug extenders for an ‘81 US 2V car? An internet search shows 2 part numbers that seem to be commonly recommended: 115647 (black 100mm) and 116613 (red 100mm). The November 1981 parts manual for my model shows 115647. The last set I bought were 116613 (red) and I was assured at the time that they were correct. I’ve read that aside from different colors (red/black) there are different lengths and even different resistances plus differences between carb and injected, 2V and 4V, and US vs. Euro. Has the part number been updated for some reason? Are they basically interchangeable? Is one better than the other? If so, why? Thanks in advance for any guidance that can be provided.
From a post I wrote last year - has links and part numbers for the various extenders used for the 308 2V and QV and 328 versions. The thread was about the 328 versions, but the others are in here too: "328 Spark plug lead extensions???", post #3: "The 328 extenders are different from the earlier QV 3 litre engines (and the earlier 2V injected engines are different again, they used a black version of the shorter 308 QV extenders. There are quite a few references here in earlier threads, I went through them last fall when I was building new plug wires for my XDI-converted 308 QV. From the Ferrariparts.co.uk catalog, Diagram 42 - Ignition, part number 126699 is the correct 328 extender - notice the 3 flats below the top connector, like your old extender in your picture above, and they're 107 mm length. https://www.ferrariparts.co.uk/part/ferrari/126699 If you compare to the 3.0 2V extenders like on the 308 GTBi/GTSi, diagram 37 Ignition, part number 116613 looks like the part you received - no flats on the top of the extender insulator, and as you've found, the length is different as well - 100 mm. https://www.ferrariparts.co.uk/part/ferrari/116613 You want 126699, watch for the 3 flats on the top of the insulator part of the extender. AW Italian shows both of these parts as listed for the correct models, mentions the different lengths. https://www.awitalian.com/product/spark-plug-extension-red-107-mm-long-126699.html/ https://www.awitalian.com/product/spark-plug-extension-red-100-mm-long-fits-4-valve-euro-cars-only-116613.html/ There's also a black version of the 100mm long version, part number 115647 - https://www.awitalian.com/product/spark-plug-extension-black-100-mm-long-115647.html/. No matter, for the 328 you definitely want the 107mm long red extender part number 126699. Your vendor sent you the wrong versions." Cheers, Gordon
Now for the next question: the red extenders I have seem to be correct for my 2V, and I recently measured the resistance (about 2k ohms). The owners manual recommends both resistor and non-resistor spark plugs. Does it matter which plugs are used with the resistor extenders?
He just gave you a part number for a 328. You said you have a 2 valve 308. They will be a different length. The 2v and 4v heads have different well depths. We never used resistor plugs in them.
Yes, the original post was for a 328, but it also outlined the correct extender for a 2V 308, so that info was useful. Sounds like I don’t need resistor plugs, then, since my extenders have resistors.
