If you're willing to go dual point, which means you don't care about
stock anymore, go electronic ignition. Check out the Pertronix
Ignitor. Uses stock everything, and fits COMPLETELY under the
rotor & cap. I have (had) it on: 70 240z, 72 Chevy 1ton, 69 Mach I,
72 F100 4x4, and my 77 TR7.. It works great.
I've done dual points on many cars, including the mach I, but it's a
headache that's not worth it... Avoid it like the plauge.
>
> Concerning my 1967 TR-4A IRS...
> I'm plagued with a continuing miss which begins at 2500-3000 rpm, and
> makes the car practically undrivable on the highway. I've replaced
> points, rotor condensor, plugs, wires, coil, distributor base plate,
> and springs on the centrifugal advance/retard system. I've sealed the
> leaking vacuum advance diaphram as recommended by another reader
> (which seemed to work), but my miss continues. The points don't last
> long (the coil sees 12 V, there is no balast resistor). I installed a
> hotter coil (Accel) which helped some. I've opened the plug gaps a
> bit, but that doesn't seem to help. I've replaced the needles and
> jets and rebuilt the carbs--I think they are set up properly. I
> rebuilt the fuel pump.
>
> It does smoke a bit, but the plugs will last six months or so before
> becoming so fouled that they are a problem. (but I will try a new set
> just to rule them out--the problem was much less when they were new.)
>
> The only symptom that gives me a clue is the variation in the timing;
> I can see the timing mark swing about under the strobe. From a
> nominal position (about 0.75 to 1.0 inch on the circumference of the
> flywheeel pulley before top dead center) the mark will move around
> almost to the TDC mark. I believe that this fluctuation is caused by
> some "jerkiness" or friction in either the centrifugal or vacuum
> advance system, but maybe there is another cause. There is no
> significant slop in the distributor bushing, as far as I can tell.
>
> Another strange clue...the rotor has a dark smudge indicating (to me)
> that the spark is jumping from one corner of the rotor; I would expect
> this smudge to be more central on the arc-shaped brass rotor surface.
>
>
> _______ * smudge here, I think
> (===== )
> ( " )
> ( )
> \___/
>
> Top View of Rotor (imagination required!)
> (drawn from memory, and I don't have much of that anymore!)
>
> I'm trying to figure out how it may be that the rotor doesn't align
> with one of the plug wire terminals when the points open; even if the
> timing is right...I have made everything correct, I think, except that
> I haven't removed the gear sits on the cam shaft to drive the
> distributor. If this is off one tooth, would it cause my problem?
>
> I'll welcome any advice or ideas. I'm about ready to chuck the
> distributor and install a Mallory (or just install electronic
> ignition, but if the problem is in the base plate or advance system, I
> haven't solved anything this way)
>
> Anybody got a Mallory distributor for sale cheap?
>
> Thanks,
> Ray
>
>
>
>
>
> -------------------------------------
> Ray W. James, P.E., Ph.D.
> Civil Engineering Department
> Texas A&M University
> College Station, TX 77843
> Phone (409)845-7436; Fax (409)845-3410
> E-mail: r-james@tamu.edu
> Date: 09/24/1999 Time: 3:38:31 PM
> -------------------------------------
>
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