TR4/4A Turn Signal Flasher and Perceptions

[KVH]

I have three "new looking" turn signal flashers in my possession. One is one year old, another is two years old, and another I purchased two weeks ago. The two year old one "blinks" great, but won't send or allow a signal to my dash indicator light. My one year old one isn't working at all. It sticks, goes fast, goes normal, or doesn't go at all. My new one works fine--for now.

I love these cars, but what must an independent onlooker think when he sees your admiration for a vehicle that runs through water pumps, starter brushes, points, and turn signal flashers every few years, or even more frequently, requires clutch cylinder and brake cylinder rebuilds about as often, has a horn that works when it feels like it, overheats at summer stoplights no matter what you try, and leaks oil all over your garage no matter what you do?

I guess I don't care, but it makes me think.

 

[TR3driver]

An important point to keep in mind : These things did NOT happen when the cars were new. Defective aftermarket parts are an unfortunate fact of life, but not Triumph's fault! And in general, parts availability today is excellent. Many other marques have a much harder time finding parts that even fit, let alone last a long time.

BTW, I've been running the same flasher for some 10 years now, a Tridon EL13. The one before that only quit after the plastic case broke (from the clip being too tight).

 

[KVH]

Is there a way to fix a flasher? I took my totally bad one apart and see a cheap primitive copper switch of some sort. Each time it fails to click properly I see a tiny spark where the connecting points are.

About the car, I was just ranting after realizing that no one can believe the time I spend on it. But you're right. Amazing parts availability and a survivor through the decades. Leaves other marques in the dust.

 

[TR3driver]

I guess you could try cleaning the points, but I'd go ahead and replace it. Just cleaning isn't going to restore them to new, so the next failure will probably be even sooner.

A Triumph part cheap and primitive? Nah, couldn't be!

Seriously, the mechanism is simple, but also somewhat ingenious. The moving arm consists of two different types of metal bonded together (known as a bimetallic strip). When the strip is heated, the metals expand at different rates, causing it to bend. The strip has a heater, basically just a length of heater wire wrapped around it with some insulation to keep it from shorting. For a standard "load sensitive" flasher, the heater wire is in series with the contacts. When the contacts are closed, the current for the turn signals runs through the heater wire, heating up the strip, causing it to bend and open the contacts. Once open, the circuit is interrupted, the strip cools, and the cycle repeats. Pretty cool in my book, especially considering it was invented several decades before the transistor! Probably not many on new cars today, but they were still common as recently as ten years ago.