RE: Implications of wrong TR6 distributor?
>>Well, the more closely I look at my car, the worse I feel...
>>
>>My car is titled as a '75. It has a late (recessed) block, and carbs and
>>head from a '74.
>>
>>This weekend's discovery is that the distributor is apparently from a '71!
>>It has the number 41352B stamped on the case, and according to the Bentley
>>manual and the Moss motors catalog, that should be on a '71.
First of all, as far as I've been told, lots of foreign cars, even into the 70s
were titled as being cars from the year they were sold, so your car could be,
and probably IS, a 1974. Use the serial number to determine that and take the
year on the title with a grain of salt, or a pint of bitter, whatever you like.
Don't worry about it, though.
I don't know must about TR6s, but if I look at the performance figures for
the same period MG Midgets, I can see why someone probably swapped
distributors. Up until 1972, the emissions control consisted of an air pump
and not much more. After that time the carbs started to be more and more lean
and the distributor curve was longer. I'm not sure of the theory involved with
all of this, but reduced emissions was the goal. I don't know whether reduced
emissions were actually achieved, but reduced performance was. If you have the
1971 disi, use the 1971 settings. The total advance on the 71 disi is probably
less, but it kicks in sooner. You have to compensate by having the correct
amount of initial spark advance, which is probably more than the 74/75 setting
( because the disi has more advance over its long curve). If you use the 71
disk with the 71 settings, you'll probably get a bit more performance and
better running than using the 71 disi with the 74 settings (or even a 74 disi
with 74 settings).
I would probably use the 71 needles, too. They should be a bit richer and give
you more power than the 74 needles. I'm assuming, of course that other
aspects of the engine setups didn't change between 71 and 74. If the intake
or exhaust systems are radically different then you probably shouldn't mess
with it without some advice from a TR6 nut.
Hope this helps,
-Al (off to Watkin's Glen tonight... Collier Cup is Sunday!)
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