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Long coil leads
Posted: Mon Nov 04, 2013 1:14 am
by Vegard
I'd like to use this on my race car:
http://item.mobileweb.ebay.co.uk/viewit ... 0418469893
I remember that Miglias ran loooong coil leads when running with dizzys.
Is there a downside running such long lead?
I
Re: Long coil leads
Posted: Mon Nov 04, 2013 1:31 am
by ivor badger
Long coil lead allows the coil to be moved from the engine to the bodyshell, preferrably inside the car for the wet. This stops the engine vibration shaking the inside of the coil to pieces.
Re: Long coil leads
Posted: Mon Nov 04, 2013 9:16 am
by Vegard
Yes, that I understand, but is there a downside in using a long lead? Will the spark be postponed

Re: Long coil leads
Posted: Mon Nov 04, 2013 9:18 am
by rich@minispares.com
Re: Long coil leads
Posted: Mon Nov 04, 2013 9:21 am
by Vegard
I'm aware I might come across as an idiot, but I just needed to have it confirmed.
(It's not the first time
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)
I've heard about insulating the lead as well, so clearly, something is affected somewhere
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Re: Long coil leads
Posted: Mon Nov 04, 2013 12:14 pm
by ivor badger
Vegard wrote:Yes, that I understand, but is there a downside in using a long lead? Will the spark be postponed

Yes, so you will have to measure the extra length of the lead and then calculate the retardation time of the spark. Then convert the retardation time into degrees for the rpm you are adjust the timing accordingly.
Re: Long coil leads
Posted: Mon Nov 04, 2013 12:21 pm
by rich@minispares.com
ivor badger wrote:Vegard wrote:Yes, that I understand, but is there a downside in using a long lead? Will the spark be postponed

Yes, so you will have to measure the extra length of the lead and then calculate the retardation time of the spark. Then convert the retardation time into degrees for the rpm you are adjust the timing accordingly.
from memory its 1/2 a degree for every 6" extra of length of lead, unless its 8mm double silicon, in which case its 2/3rds of a degree

Re: Long coil leads
Posted: Mon Nov 04, 2013 1:48 pm
by Vegard
Bastards!
So theoreticly, I could have a coil lead which was 80.000yds long, and there would be no problem?
It's not a bloody Superconductor at £13.19 is it?
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Re: Long coil leads
Posted: Mon Nov 04, 2013 3:57 pm
by CooperTune
10,000 comedians out of work and we get these guys? When I bought all my MSD stuff one of those came with it. All I could think of was two more chances for a bad connection. I mount the coil as close to dizzy as possible. How many known, truely tested bad coils have you had? The longer the run the more chance for an issue. Steve (CTR)
Re: Long coil leads
Posted: Mon Nov 04, 2013 7:17 pm
by slowboy
0,000 comedians out of work and we get these guys? When I bought all my MSD stuff one of those came with it. All I could think of was two more chances for a bad connection. I mount the coil as close to dizzy as possible. How many known, truely tested bad coils have you had? The longer the run the more chance for an issue.
that's to the point, and just what I was thinking , I have never had an issue with the coil on the bell housing on the rally car, and the front end has been under water, many times !, good solid connections , a good rubber cap, and red waterproof grease, no need to go in the car and through the bulkhead in my opinion for what its worth
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Re: Long coil leads
Posted: Tue Nov 05, 2013 8:28 am
by andy1071
You are also likely to get a voltage drop with the increased length (I have no idea how much though!)
And there must be more chances of problems with induction/short-circuits etc.
Basically, the longer the cable, the more chance of problems...
Re: Long coil leads
Posted: Tue Nov 05, 2013 8:32 am
by mk1
Basically, the longer the cable, the more chance of problems...
I agree, I did like Rich's theory though
