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Plug leads & cross arcing
Posted: Fri Jun 27, 2008 6:04 pm
by winkle
Maybe this has been raised before, but Ive seen loads of pictures of V8 engines (often competition or modified) with the plug leads cable tied in pairs. ie; touching each other. Im well aware that according to many people there can be a problem with cross arcing, hence plug wire separators.
i'm curious to know; are plug leads better quality now so cross arcing isnt a problem or is tying them together still a no no?
Steve
Posted: Fri Jun 27, 2008 7:51 pm
by stevieturbo
Ive seen leads routed and bunched in some extremely bad ways, on some very fast cars.
So either modern leads are very good....or all the talk about cross arcing or firing, is nonsense.
Posted: Fri Jun 27, 2008 9:38 pm
by mgbv8
My Mallory and Magnecor leads can be touched together and they dont short out.
Posted: Sat Jun 28, 2008 6:41 pm
by ChrisJC
If the leads were prone to arcing in any way, then dirty or damp leads would give a misfire.
I think with modern leads, it really doesn't matter. The leads just work properly.
Chris.
Posted: Sun Jun 29, 2008 1:09 pm
by winkle
Cheers guys, its not that important cos I could use separaters but I think they look neater if tied in pairs.
Ive just bought some MSD helicore leads and with the instructions it says they
must be separated particularly with cylinders 5&7 because they fire in sequence, if cross arcing occurs one of them can run lean causing damage!? But as I have seen, and you have said it never seems to be a problem.

Posted: Sun Jun 29, 2008 2:15 pm
by CastleMGBV8
Steve,
Sounds like your making progress, I remember having a missfire problem with my 3500S which I bought new back in 1973, it went back to the dealers several times and they never completely cured it, it was obviously caused by the arcing between 5 & 7 a combination of poor quality leads and not seperating the 5 & 7 leads in the holders. but of course I didn't, and neither did the dealer know that at the time and we didn't have the benefit of the internet and boards like this one to help with problems.
Kevin