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TR6 The Importance of Tiny Parts in Distributor

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SherpaPilot

SherpaPilot

Jedi Hopeful
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I live in central Texas and owned my TR6 for 39 years. Two years ago my engine and transmission went through a professional rebuild. During the rebuild I sent the distributor to Advanced Distributors in Minnesota for overhaul and recurve. They did a great job and sent the unit back with some advice. They advised to shed the electronic ignition and stick with the stock point system. The concern with electronic is stray voltage and arcing within the distributor cap. I followed this advice and retained my point system. Fast forward to this week. It was a beautiful "top-down" day for the TR6 and I took the Triumph out for a run. While enjoying the car, suddenly it began missing, back-firing, running rough and forcing me to put along at 5 mph. My first thought was the failure of the timing chain. With lots of effort, I was able to get the car back home and into my garage. Over the next day, while trying to figure out this problem, I discovered within the distributor the thin plastic insulation plug that rides in the points had cracked and broke off. Therefore the sudden missing and rough firing was simply an electrical failure. I had changed these points many times since the rebuild and that small plastic washer was always changed. It never dawned on me how important that little thing was. So the point of this story is the big things get blamed but sometimes the tiny small things are the culpret.
 
Hmmmm....I don't know what "stray voltage" is, and electronic ignition will not cause arcing any more than points will. Unless it's a CD ignition, the high-voltage waveforms will be the same. In fact, with electronic ignition the voltage at the points will be lower. The broken insulator probably would have killed the ignition, though, either way.

Shortly after I got my restored TR4A on the road, it died suddenly. Looking at the engine, I saw immediately that the wire from the coil to the distributor had broken. I had reused the existing jumper, which may have been original. The insulation hardened and that led to the wire fatiguing.

I have a term for electrical and electronic things that are 99.99% working: broken.
 
Thanks a bunch for your response. The comments concerning electronic ignition were not mine but those of Advance Distributors (highly respected among most car guys) After my distributor was rebuilt, it was returned with the used cap. He marked the interior of the cap to show arc evidence. He also advised that a stock TR6 will loose 39 hp on a dyno with electronic conversion. I am by no means any electronic expert who can argue either point. Turning the radio on and off are my limits of electronic knowledge.
 
Im no expert but points and electronic ignition are just switches.The selling point of EI is no maintenance and the ability to handle higher voltages,allowing hotter coils.If the stock coil is used there should be no higher voltages to stray.Higher voltages from hotter coils will put more stress on insulation.
Any drop in hp from EI makes no sense.
AD also did my dist.and I also stuck with points.
Tom
 
SherpaPilot said:
Thanks a bunch for your response. The comments concerning electronic ignition were not mine but those of Advance Distributors (highly respected among most car guys) After my distributor was rebuilt, it was returned with the used cap. He marked the interior of the cap to show arc evidence. He also advised that a stock TR6 will loose 39 hp on a dyno with electronic conversion. I am by no means any electronic expert who can argue either point. Turning the radio on and off are my limits of electronic knowledge.
Click to expand...
Tom has it right, in that most electronic ignitions are "points elimination" ignitions, which simply use a transistor instead of a mechanical switch (points) for firing the plugs. That's all. The waveforms are the same, the spark energy is the same. Capacitive-discharge ignitions are different, though, and a comparison gets more complicated, but it's hard to make a case that they are inferior to conventional points. Very easy to make the case that they are superior.

There may be some arcing evident in your cap, but the electronic ignition has nothing to do with it. And the claim of losing 39 HP with electronic ignition could not possibly be right.
 
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