I spent a few hours last night reviewing the sad state of affairs with the
coil on my 2.5 PI with dual SU's and solved a few of the problems. More than
a few list members offered suggestions as to what it meant that the wiring
diagrams refer to a 6 volt coil, how to check the coil and so forth. I thank
you all. I have never seen a 6 volt coil before and wondered if the current
12 volt coil (no pun intended) was the cause of the hard starting and poor
running above 3000 RPM. Thanks to the list, I have identified the following:
1-It's not supposed to be a 6 volt coil, rather a 12 volt with an external
ballast resister (which is missing from this car) which drops it to 6 volts.
I found a Lucas part No. in one of the manuals, and it matched an early TR6
coil-of which I had a spare!
2-The coil on the car tested out with excessive resistance for even a
ballasted coil. The specs I looked at called for 1 to 2.5 Ohms for a non
ballasted coil and 4 Ohms for a ballasted coil. This one has 6 ohms. I don't
have a full understanding of what makes a coil go bad, but I'm working off
the assumption that this is bad.
3- The PO had removed the switched 12 volt primary wire from the starter
lug, probably thinking that he had 12 volts all the time without the
resister. Thus the hard start condition. In case you are wondering, I'm sure
it was removed, not simply fallen out, based on the taping job.
4- Someone suggested that the carbs were probably the cause of the high RPM
power fade, and I agree. With the carbs removed, I know for sure. One of the
carb bodies is cracked on the air intake side. It might be repairable. These
are a later version of the 1.75" SU's, with 3 air filter bolt holes, unlike
the TR4 version in that respect and also much shorter runners. AUD9. Does
anyone know what other cars used this later version?
I will never, ever buy a car again without going to look at it. This car was
purported to be in excellent shape, sold by a lawyer who works for an auto
club, was active in things Triumph. I specified that I didn't have the time
to buy a car I needed to work on due to my other projects. I even had
someone off the list go look at it, but I don't fault him. This car was on
the brink of disaster, and only the owner would have been able to tell. Just
a warning!
Anyhow, thanks to all that answered my plea. Once I get the carbs
straightened out I let you know how she runs.
Bob Kramer
TR6, TR4A, TR4
Hill Country Triumph Club
Corinthians Vintage Auto Racing
rgk@flash.net
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