32b Posted August 3, 2008 Share Posted August 3, 2008 Hi All,I have just purchased 6 new spark plug leads from rimmer bros for my vitesse 2litre,only to find that two are of a reasonable length but the remaining four leads are way too long.Is it possible to cut these leads down to size and if so by how much,will it effect the timing etc.Any replies on this matter will be gratefully received regards Paul Link to comment Share on other sites More sharing options...
Steve Cureton Posted August 3, 2008 Share Posted August 3, 2008 Cutting them down won't affect the timing but the ends are usually crimped, so cuting them down is not usually an option. Are you sure you've got them routed correctly? I'd be inclined to leave them as they are and just coil the extra length out of the way by taking them the long way around the dizzy. Link to comment Share on other sites More sharing options...
Deleted User Posted August 3, 2008 Share Posted August 3, 2008 Steve_Curton wrote:Cutting them down won't affect the timing Time to be a pedant.At 4000 RPM, cutting 1cm off the lead will advance the timing by about 0.0000001 degrees :X Link to comment Share on other sites More sharing options...
Steve Cureton Posted August 4, 2008 Share Posted August 4, 2008 Have we stumbled on another to adjust our timing - a boot full of different length HT leads? Now how many CM does that equate to to retard the ignition by 1 degree and where would we hide the excess? :-/ Link to comment Share on other sites More sharing options...
Freebird Posted August 5, 2008 Share Posted August 5, 2008 Too silly, too silly. Get some discipline into those men Sgt Major!Anyone remember that line? Link to comment Share on other sites More sharing options...
Deleted User Posted August 5, 2008 Share Posted August 5, 2008 Steve_Curton wrote:Have we stumbled on another to adjust our timing - a boot full of different length HT leads? Now how many CM does that equate to to retard the ignition by 1 degree and where would we hide the excess? :-/The speed of light is about 300,000,000 m/sThe propagation delay factor in cable is usually about 80%, so the spark will travel down the HT lead at about 240,000,000 m/s.As the crankshaft is rotating, the amount of advance or retard for the subtraction or addition of a set length of cable will vary with the engine speed.At 1000 RPM, the crank rotates at 16.67 times a second, so one degree of crankshaft = 0.000167 seconds so for 1 degree of delay you would need about 40,000m of HT lead !At 2000 RPM, the crank rotates at 33.33 times a second so one degree of crankshaft = 0.0000833 seconds so for 1 degree of delay you would need about 20,000m of HT lead etc. (whistle)(whistle)(whistle)(whistle)(whistle)(whistle)(evil) Link to comment Share on other sites More sharing options...
Steve Cureton Posted August 6, 2008 Share Posted August 6, 2008 That's very interesting, so what we need is HT lead that can somehow shorten or lengthen itself dependant on engine speed and of trailer with some sort of a cable coiling device. what about ambient temperature, I would have thought that would influence it too? ::) ;) :P ;D :-/ Link to comment Share on other sites More sharing options...
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