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Distributor Woes....

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In my quest for a high performance TR6 I have run across more than my share of stumble blocks, the latest which is my newly rebuilt distributor. This is a Lucas 22D unit that has been freshly rebuilt. [An aside before I get to my question: I installed a Pertronix electronic ignition, seemed to work ok but noted that one dash light burned out (the one on the black plastic heater bar) and went out this morning to find the ignition courtesy light stuck on all night. (Mickey, if you weren't monitoring this, I would let loose with a really vulgar expletive right about now - everyone feel free to use your imagination at this point). And, I have steam-like vapors coming up from the somewhere behind the engine after a hard run.] Anyway, to the question. I seem to be misfiring at speed and can't really get the power curve to what it should be. Inside my dizzy I notice that the cam cannot be turned by hand to the stop. The arm is marked 16 degrees. If I play with the bob weights, switching them around or flipping them over, I can get the arm to max out. I think that one of my weights is binding or catching and won't allow my cam to advance the spark! Can I grind on these weights ever so carefully to make them work without binding or am I missing something here? Seems I can free up the whole thing with a little selective polishing here or there. The alternative is send it back to the rebuilder but I am of the mind that if I can break it, by golly I sure want to try.
I will address the smoke/steam and mysterious short circuit at a later post. Oh, and by the way, the Pertronix is history. I gotta blame someone on the smoke, may as well be them. Besides, it is made in China. Bummer.


Bill
 
Hello Bill,
is the asembly free to turn when you remove the springs? It is unusual for this mechanism to bind unless seized due to neglect, which your re-built unit won't be. If it is not free then there is something wrong, and being such a simple mechanism should be obvious. You will note that the two springs are of different strength which gives a two stage advance curve. The best check at home is to do a strobe check of your advance as you rev the engine. (Don't forget that the 16 degrees will give 32 degrees engine advance.)

Alec
 
Bill:
If you are polishing the pivots there should be no alteration of the design intent of the advance. Technically, any weight reduction would change the curve but I don't think there would be any significance. If you can find an old sun tune up gadget, it will spin the dizzy and allow you to measure the advance at any RPM and you can check it to your spec's, changing springs or altering weights to suit. I suspect your fly weights are machined rather than the OEM press pieces that were in my '74 dizzy and the machined ones would have more attention to uniformity.

The advance is a function of the shape of the weights and the spring tension seems to be even more important than altering the shape of the weights. BTW, does your new dizzy get lubed like the OEM's?
 
Alec and VD,
Ignorant me, I have the dizzy in hand and noticed that applying spinning torque from the drive dog by hand motion (sans springs, of course) will give me the desired action of the weights and allows the cam to advance all the way to the stop. Must be a function of the simple design that won't allow these same weights to open up whilst trying the same motion from the top. Does that make sense? Does it make sense that someone is holding onto a distributor at 5 O'clock on a Sunday morning? What is the proper lubricant to lather up all these moving parts with?

Bill

post script: the old saw mechanic friend that first noticed that the cam wouldn't turn by hand with the distributor insitu was freaking out that he couldn't grab aholdt to the rotor and turn it counterclockwise to the stop, against the action of the two springs. Seems to me that this is an unnatural motion anyways and what is the big dif? Should one be able to perform this act, that is, turn the rotor and therefore the cam mechanism against the spring action and touch the stop, and is this a run-on sentence?
 
Hello Bill,
there is normally some movement when you turn the rotor arm but not necessarily full advance, which is why I suggested doing a strobe run. (If you can get a distributor tester so much the better.)

Alec
 
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