F1loco Posted August 27, 2016 Report Share Posted August 27, 2016 (edited) So, I recently was having nice morning run when my '64 TR4 started to sputter and knew it was about to die. And of course, it did. The coil was super hot and luckily I had a spare in the trunk. Swapped it and no problems, until I was almost home and the same thing started? I am running a Pertronix electronic ignition. I've noticed it idles in garage just fine, but once it's in gear and under load is when the problems start. I'm getting a good 12.7 volts on the ignition wire from the key switch going in. However, when it's not running, key on, I'm only reading 10v at the coil and when it's running it is only registering 5-6v. It is a positive earth system. Is this too weak? I had been running Bob Wilton's Solid State conversion voltage regulator, but someone previously suggested I swap back to wound coil type, which I did, but same issues. Suggestions? I heard that the distributer rotor cap can cause issues and short out on the shaft causing a weak spark, which somehow loads the coil, despite the weak spark? I am running a RED one, but I heard that even the Lucas ones are red but poorly designed. I am still reading 3 ohms on the coil from the + terminal to the where the wire from the cap plugs into. The only other thing I noticed, that despite a fresh battery charge, the AMP gauge at idle is just barley +, but once I floor the gas, it will spike to 15+, but eventually settle back down. Still have an old generator and no alternator conversion given the positive earth wiring. That said, I just checked the newly fresh charged battery that cranked w/o issue and idles w/o issue but it is only pulling 8.9v now? Then the reading into the coil is only 1.2v. Could a bad generator be the blame for all the above? Or is it just a bad Pertronix unit? Thoughts, suggestions? Cool air is coming to Florida eventually and want to be ready... Edited August 27, 2016 by F1loco Quote Link to post Share on other sites
RobH Posted August 27, 2016 Report Share Posted August 27, 2016 If you are measuring at the battery side of the coil, the readings you get are odd - but that may depend on what Pertronix unit and coil you have. Could it be a ballasted coil perhaps? The meter readings may be confused by the ignition spikes and reading wrong when the engine is running - or the meter may just be duff. I would check that the meter is OK first. If the battery really is low enough to read 8.9v off load it is unlikely it will be capable of starting the engine. Also the ammeter would be indicating a very high charge all of the time the engione was running. Since the failure has happened with two coils it might be worth substituting the Pertronix unit if you can - just to check that out. I once had a positive-earth Pertronix (the points-substitute type) which died when it get hot and recovered as it cooled down. The ammeter readings you describe sound about right. Quote Link to post Share on other sites
john.r.davies Posted August 27, 2016 Report Share Posted August 27, 2016 Whynot ask Pertronix Europe via their contact page? http://pertronixeurope.com/contact.php John Quote Link to post Share on other sites
F1loco Posted August 27, 2016 Author Report Share Posted August 27, 2016 Thanks. Sent Pertronix an email already. Have to go get another meter - it read 8.9v, but inverting the leads, gets me a -16.5? Something is not right. Was going to check the regulator is cranking the voltage at 3K rpms and cutting out correct, but need a new meter apparently. Quote Link to post Share on other sites
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