PaulAA Posted September 7, 2013 Report Share Posted September 7, 2013 Chaps HS6s are bought and being couriered, but, in the meantime, I’m experiencing some low-rev misfiring when the engine is warm, which I am inclined to believe is due to the age of the leads and the coil. The set up appears unfettered, with an unmarked plain metal Lucas coil and old-ish looking HT leads. The PO installed electronic ignition (it came with a 123ignition leaflet), but the dizi is otherwise original. I believe that the best approach to the low-rev misfire is to replace the coil and HT leads and I have in mind to install a Lucas DLB105 and Magnecor HT leads, but, being a ’75 CF, I assume that the coil is ballasted. I read somewhere that it should be possible to omit the ballast wire altogether, by connecting the yellow-on-white cable from the starter relay directly into the fuse box (I’ve a spare connection on the ignition circuit). Looking at the wiring diagram (extract below), it stands to reason that it will by-pass the ballast resistor wire, but won’t it also by-pass the ignition switch altogether? If omitting the ballast is not so simple, is it better to leave it untouched and stick with a standard 6V or 12V coil (I haven’t determined which it is yet). Guidance gratefully received. Paul Quote Link to post Share on other sites
TrRob Posted September 7, 2013 Report Share Posted September 7, 2013 When you've an electronic ignition go for a 1 ohm coil like the blue Bosch. Quote Link to post Share on other sites
TR NIALL Posted September 7, 2013 Report Share Posted September 7, 2013 The Coil has to be comparable with the Electronic ignition. Quote Link to post Share on other sites
whatmore179 Posted September 7, 2013 Report Share Posted September 7, 2013 Pertonix flame thrower. Perfect. Steve Quote Link to post Share on other sites
silvertop_john Posted September 7, 2013 Report Share Posted September 7, 2013 The Coil has to be comparable with the Electronic ignition. Definitely worth checking - I've just installed a CSI distributor, and needed to make sure that the coil was at least 3 ohms. John Quote Link to post Share on other sites
Ragtag Posted September 8, 2013 Report Share Posted September 8, 2013 It seems to me that the modification that you are proposing won't achieve the desired result, if you are trying to replicate the earlier 12v system. The yellow/white wire from the starter solenoid is only live when cranking, its job being to provide 12v for starting. The wire you need to bypass is the wire marked K/W (pink/white?) which is ballasted to provide 9v for running on the standard system. Having done this, the Lucas DLB105 can be used. Regardless of ignition system, Magnacor leads and a genuine rotor arm from the Distributor Doctor are both worthwhile upgrades, particularly if your existing leads are manky and you are unsure of the source of the existing rotor. Warning. It would be worthwhile trying to identify your existing electronic ignition. I'm no expert on 123 but I was under the impression that it is a complete replacement distributor not a replacement for the 'guts' of an original but I may be wrong on this. Ignition systems such as Pertronix/Aldon require a 12v feed whereas others may not tolerate 12v.....you need to be sure. Finally, if you want to identify your existing coil, the number should be stamped on the bottom. Hope this helps. Quote Link to post Share on other sites
PaulAA Posted September 8, 2013 Author Report Share Posted September 8, 2013 (edited) Chris Thanks for your comments. I think you're right about the K/W wire, but the two obstacles to a confident solution are that the coil is completely without marking, even underneath, and the electronic ignition, upon shrew inspection, turns out to be good old points . Below is an image of the open distributor: On that basis, I assume that simply replacing the dodgy coil with a Lucas DLB110 would be the line of least resistance to eliminating the misfire. If it isn't, I'll assume that the dizzy, being of pensionable age, is worn out. The rotor arm looks standard (equivalent to DD's red rotor no. 418726), so I'll include this in the shopping list. Cheers Paul Edited September 8, 2013 by PaulAA Quote Link to post Share on other sites
RogerH Posted September 9, 2013 Report Share Posted September 9, 2013 Hi Paul, the CB points in your dizzy look awful. There is a lot of carbon deposit all around the base plate. Rather than go mad and change everything in one go why not attack each item at a time to see what is causing the problem. I would start with the points and the associated capacitor (get of Martin Jays). If more is needy then go for the Coil etc etc. Roger Quote Link to post Share on other sites
PaulAA Posted September 9, 2013 Author Report Share Posted September 9, 2013 Hi Roger Good call and points & condenser being ordered from Martin right now. The current leads are past their prime, so I've already splashed out on them. Paul Quote Link to post Share on other sites
RogerH Posted September 9, 2013 Report Share Posted September 9, 2013 Hi Paul, eventually renew ALL the suspect parts but replace one at a time to find the fault. That way in finding the fault you will have no nagging doubts when once on the road. Roger Quote Link to post Share on other sites
Quentin Posted September 9, 2013 Report Share Posted September 9, 2013 Change the last part first. It's always the last one for me Quote Link to post Share on other sites
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