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What is the official name of this plate and where can I buy one

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Ok I installed a ballast resistor, but am still getting the same stumble under load while accelerating. Which bring me back to my question of could it be my alternator not being able to supply enough current to the 40,000 volt Pertonix coil? Im running out of things to replace.

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It's probably not the alternator, unless the voltage is decaying. Did you check your timing w/o load? Is the advance working? If the advance isn't working, you may be able to work around it by advancing the static timing a couple of degrees.

By the way, I wasn't sure whether or not you could wait on the mounting plate. I might be able to get to my distributor swap in three weeks.

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My advance is working. This stumbling under load is driving me crazy.

New cap, wires, dizzy, rotor, coil, pertronix ignition, Ztherapy carbs, ect...

I am at a total loss. The only thing I can think of now is that the ohm resistance might not be correct, since it's just a generic over the counter on from the auto parts store, and not a Datsun one. I'm still trying to figure the correlation between high rpm stumbling and the ballast resistor anyway.

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I have an extra 73 distributor. It has the plate as well dual points. It feels solid and tight. jlp

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What's the advantage of dual points? Would running dual points offer an advantage over the Pertronix ignition? I'm willing to try anything at this point. Including another dizzy using dual points.

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What's the advantage of dual points? Would running dual points offer an advantage over the Pertronix ignition? I'm willing to try anything at this point. Including another dizzy using dual points.

Can someone else weigh in on this. I am not sure what the advantage was of dual points but I believe they were considered superior to the single point distributors. jlp

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I didn't think there was an advantage, they where just a stepping stone to "reluctor" style distributor's.

In any case, they didn't hang around for long, just like flat tops.

Little point in changing over, sure this is a electrical problem and not fuel related?

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Don't think it's carbs, have a brand new set from Ztherapy. 3 turns out, floats ajusted spot on. Could it be I have a non standard ballast resistor? Although I'm still not sure how any ballast resistor would have anything to do with high RPM running.

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But it could be fuel delivery.

Fuel pump, restriction in pipe before carbs etc.

If your fuel pump can't keep up then you're going to starve of fuel.

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All the ballast resistor does is to limit voltage to the coil after start up.

The intention is to drop coil voltage to 8-10 volts (someone will correct me on this as I'm writing off the top of my head) after providing full volts for the start up.

The worst that could happen is to burn the coil out, this doesn't appear to be your problem either.

Good luck, we're all waiting for the solution.

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Can someone else weigh in on this. I am not sure what the advantage was of dual points but I believe they were considered superior to the single point distributors. jlp

The dual point distributor for the Z is (was) only used in automatic transmission cars. The two sets of points operate separately, but only one set at a time. One set is has different base timing setting than the other. One set is used normally and the other set is used under certain conditions to lower emissions. This is not a performance enhacing set-up.

The hot rod dual point set-up is used to increase dwell which helps high rpm performance with high power engines. The two sets work together, on set making the circuit and the other breaking the circuit. The advent of electonic ignition and computer controlled (adaptive) dwell seems to have place the dual point set-up in the closet next to the phonograph.

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The dual point distributor for the Z is (was) only used in automatic transmission cars.

Overall very informative, thanks. The dual point distributor I have came off a 1973 manual transmission car and is purely mechanical advance. It must be an aftermarket performance distributor. jlp

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I have plenty of fuel to the carbs. This feels like and electrical problem not fuel.

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The Pertronix system has an adjustment for the air gap between the pick-up and the magnetic trigger (the black plastic ring you press onto the points cam). Perhaps the gap is too large?

Check the voltage at the ballast resistor (with respect to ground). One side should be battery voltage, about 14 volts when the eninge is running. The other side should be about 9 or 10 volts at idle and rise to about 12 volts at high engine speed. Low voltage on the 14 volt side indicates a bad connection somewhere (or a weak charging system). Low voltage on the 9 volt side indicates a bad or incorrect ballast. The original ballst should be 1.6 ohms when cold (68 degrees F). The Pertonix coil might need a different value ballast. Check with Pertronix.

If the voltage at the 14 volt side of the ballast is low or unstable check the connectors in the primary circuit. There are a lot of connectors involved, mostly under the dash. Check them all. The factory service manual shows where each one is.

The primary circuit runs through:

The fuse box (and a fuse) - check the fuses

The ingition switch

The ballast resistor

The tachometer

A lot of connectors

If you have all the parts, put the points back on. If it runs properly the Pertonix module is bad. Another test of the Pertronix module would be to put in another Pertonix that you know to be good and see of anything changes.

The coil could be damaged from overheating if the car was run too long without the ballast resistor. Try a different coil.

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With the Pertronix set up it is recommended by Pertronix NOT to use the ballest resistor with a 40,000 volt coil (3 ohm), you will need to connect those two wires together or to put a jumper in to by-pass the ballast resistor. I just installed Pertronix w/3 ohm coil and mine is dead on. The first one I installed from them was defective and had to go back to points. You may want to remove the Pertronix entirely and install points (along with your ballast resistor and correct coil - and see if that fixes things. If it does, you will know it's your Pertroinx set up

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