TR6 Life without Spark :(

[BierRunner]

So, there I was, driving along a country road on a sunny Ohio morning, happy as Larry, however happy he is, when everything suddenly stopped. Thought is was fuel related, as did several kind hearted mechanics who stopped to assist me. However, there was none of that sputtering that occurs as the fuel stops getting to the carborators. In the end, it was suggested that there must be problem with vaccuum that was preventing the fuel from getting to the engine. Giving up, I had my sad TR6 towed to a professional who’s diagnosis was that the fuel was flowing correctly but there was no spark to make it work. In fact, while there is a ton of spark at the coil, it was not making it any further. He believes the distributor has failed and needs replacing. Unfortunately, a new distributor for a 1976 TR6 is not available. I took a look at Moss and, while I see distributors for TR2/3/4, there none for TR6.

Any ideas where we might look?

 

[bobhustead]

If there is spark at the coil, the distributor is almost entirely working. All the dist parts that make the coil give spark are under the cap. Once the coil gives up a spark, it goes out the thick wire to the dist cap and the rotor picks up the spark thru the middle tower and sends it to the outside tower the rotor is pointing at. From there it goes to the plug thru the thick wire on the tower that has received the spark from the rotor. Look for a bad cap, bad wires (mainly the big wire from coil to dist) or bad rotor.
Bob

 

[Sarastro]

Gee whiz, you don't need a whole new distributor. I'm amazed that a halfway competent mechanic could come to that conclusion. From what you said, it is almost certainly the cap. Look at the center, inside--there should be a spring-loaded graphite piece that contacts the rotor. Is it still in place?

I suppose it could be the rotor, but it would have to be something really dramatic, like a big crack.

I usually scold people for randomly replacing parts to solve electrical problems, but at this point you have narrowed down the cause well enough to just replace the cap and rotor. I'll bet that fixes everything.

 

[BierRunner]

I was skeptical, that’s why I turned to you guys. Thank you!

 

[Gliderman8]

Agree, you don’t need a distributor. As others have said take off the distributor cap and have a look. Let us know what you find.

 

[bobhustead]

I am in the "don't bother looking, just replace the cap, rotor and coil spark wire" camp on this.
Bob

 

[NutmegCT]

Couldn't this happen simply due to coil (or distributor condenser) failure?

 

[sp53]

probably the rotor

 

[sp53]

I had the same thing happen and it was the rotor. You could not tell by looking at the rotor; it looked fine. Just pop a new one on. Yeh get away from those guys.

 

[poolboy]

Yeah, if you stick around that shop, they'll be selling you another pair of carburetors because yours need a couple of fresh gaskets

 

[BierRunner]

Spoke to the shop this morning and they say they have replaced the cap, rotor and coil spark wire. I suggested they try the distributor condenser next. If that fails, I may be looking for another shop in Central Ohio. Any recommendations? I love Macy’s Garage in Dayton but they only have eight bays so there is a long waiting list.

 

[bobhustead]

Please clarify what you said about plenty of spark at the coil. What action was resulting in the spark? Where and how were you seeing the spark?
Bob

 

[DrEntropy]

Are we sure we're looking at a points type ignition system here? No "smart box" Pertronics or the like?

 

[BierRunner]

Are we sure we're looking at a points type ignition system here? No "smart box" Pertronics or the like?

Regular ignition, nothing fancy.

 

[DrEntropy]

I usually scold people for randomly replacing parts to solve electrical problems, but at this point you have narrowed down the cause well enough to just replace the cap and rotor. I'll bet that fixes everything.

I am in the "don't bother looking, just replace the cap, rotor and coil spark wire" camp on this.
Bob

This is the "best guess" advice. Caps and/or rotors can "carbon track" and fail catastrophically. It would be less likely the coil output wire would fail without some sputtering, intermittent triggering. And it'd be very unlikely all six plug wires would fail simultaneously. Only other thing I can think of would be the trigger wire inside the dizzy somehow found ground. Frayed insulation or connection failure.

 

[BierRunner]

And the winner is…a bad rotor cap!

After several weeks I had the car shipped to Macy’s Garage in Dayton and they diagnosed and fixed it the same day (after they undid all the crazy things we’d already tried). Lesson, classic cars belong with classic car mechanics.

You guys were all over it, so thank you! I do not yet have the skills to execute your advice myself so I passed it on to my local mechanic but we couldn’t get it done (not for a lack of trying though). I need to look for a class on basic Triumph repair and upgrade my capabilities. I also need to come up with an inventory of things to keep in my trunk for future…challenges.

Thanks again, you guys rock!

 

[NutmegCT]

With today's "black box engine bay" four-wheeled computers, it's a whole different skill set to work on the pre-computer, pre-electronics cars of the past.

You've learned a lot already, so now's the time to get your hands dirty and take a "basic auto mechanics" class from your local classic car club!

Congrats on finding the problem!
Tom M.

 

[Gliderman8]

And the winner is…a bad rotor cap!

After several weeks I had the car shipped to Macy’s Garage in Dayton and they diagnosed and fixed it the same day (after they undid all the crazy things we’d already tried). Lesson, classic cars belong with classic car mechanics.

You guys were all over it, so thank you! I do not yet have the skills to execute your advice myself so I passed it on to my local mechanic but we couldn’t get it done (not for a lack of trying though). I need to look for a class on basic Triumph repair and upgrade my capabilities. I also need to come up with an inventory of things to keep in my trunk for future…challenges.

Thanks again, you guys rock!

In post #11 above you said

Spoke to the shop this morning and they say they have replaced the cap, rotor and coil spark wire.

It appears that they didn't replace the cap. If they did, it would have been fixed.... just wonder what they actually did.

 

[DrEntropy]

In post #11 above you said

It appears that they didn't replace the cap. If they did, it would have been fixed.... just wonder what they actually did.

My guess? A "wallet biopsy."

 

[NutmegCT]

Maybe when the other shop said they replaced the cap ... they meant they opened the cap, replaced the rotor, then put the cap back on.