Tach Output

I just purchased a Pertronix 600 rev limiter for my Kent engined FF. The directions say to hook the various wires to the pos and neg terminals of the coil, a ground, and ... to the tach output.

I've got a Stack 8100. I've looked at the Stack 8100 schematic and just don't see a tach output. I called Stack but the guy who would know is out. I called Pertronix and the guy didn't know (but he tried to act like he was answering the question).

Is anyone familiar enough with the 8100 to help out?


Thanks,

Jim;

Call David Ferguson. Fairly confident he would be able to help you:

http://veracitydata.com/
805-238-1699

The ST8100 tach signal is via wire labels ‘ES’ (engine speed) and goes to pin A on the main connector

bear n mind that there are 2 generations of the dash. The older version uses resistive type pressure senders while the newer use transducers (4 pin connectors)

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Originally Posted by scorp997

The ST8100 tach signal is via wire labels ‘ES’ (engine speed) and goes to pin A on the main connector

bear n mind that there are 2 generations of the dash. The older version uses resistive type pressure senders while the newer use transducers (4 pin connectors)

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Thanks John. But I thought the ES wire was the signal from the coil TO the tach.

You got it. The Tacho (Tach Output) signal is normally the signal found on the negative side of the coil. If you were using some type of ignition box, then the Tacho signal might be different as the ignition system would generate it.

It looks like just the Pertronix Tach Output should connect to the ES input on the Stack ST8100.

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Right, the Stack doesn’t have a tach output (since it is the tach), only a tach input (via the neg coil in Pertronix case). If you had a MSD igniter, or similar, the Stack ES input would connect to that unit’s tach output for signal (not coil).

Quote:

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Originally Posted by David Ferguson

You got it. The Tacho (Tach Output) signal is normally the signal found on the negative side of the coil. If you were using some type of ignition box, then the Tacho signal might be different as the ignition system would generate it.

It looks like just the Pertronix Tach Output should connect to the ES input on the Stack ST8100.

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But the ES input line already is attached to the neg side of the coil.

The Pertronix unit already has another wire for that side of the coil. I'm really confused.

Quote:

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Originally Posted by scorp997

Right, the Stack doesn’t have a tach output (since it is the tach), only a tach input (via the neg coil in Pertronix case). If you had a MSD igniter, or similar, the Stack ES input would connect to that unit’s tach output for signal (not coil).

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So it seems like my Pertronix unit won't work with the Stack?

Pertronix are consider ‘standard breaker setup’

both Pertronix and ES are attached to the neg coil. The Pertronix grounds the coil (collapsing field and generating spark), the ES senses this ground pulse and drives the tach

Quote:

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Originally Posted by scorp997

Pertronix are consider ‘standard breaker setup’

both Pertronix and ES are attached to the neg coil. The Pertronix grounds the coil (collapsing field and generating spark), the ES senses this ground pulse and drives the tach

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Great. Thank you.

Quote:

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Originally Posted by David Ferguson

You got it. The Tacho (Tach Output) signal is normally the signal found on the negative side of the coil. If you were using some type of ignition box, then the Tacho signal might be different as the ignition system would generate it.

It looks like just the Pertronix Tach Output should connect to the ES input on the Stack ST8100.

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Thank you David. That looks like connecting it to the neg side of the coil.

I would move the Stack ES signal wire from the current negative side of the coil to the Pertronix Tach Output signal. That way the Pertronixs can provide an accurate "smoothed" tach signal, even when it's cutting the spark.

If you get no tach signal on the Stack, then I would add the 12V pull-up resistor (start with 2k) as shown on the bottom of the page from the Stack Manual). This Rev Limitor is just like any other ignition system with a Tacho output.

Quote:

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Originally Posted by David Ferguson

If you get no tach signal on the Stack, then I would add the 12V pull-up resistor (start with 2k) as shown on the bottom of the page from the Stack Manual).

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Already have a 47k resister in line. Had no signal on the Stack and you put something together for me.

You should be able to remove the 47k series resistor when attaching to the Pertronix Rev Limiter.

Sorry, I was unfamiliar with the Pertronix 600 and didn’t see that it had a tach output line. David’s suggestions sound like the way to go.

Quote:

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Originally Posted by David Ferguson

I would move the Stack ES signal wire from the current negative side of the coil to the Pertronix Tach Output signal. That way the Pertronixs can provide an accurate "smoothed" tach signal, even when it's cutting the spark.

If you get no tach signal on the Stack, then I would add the 12V pull-up resistor (start with 2k) as shown on the bottom of the page from the Stack Manual). This Rev Limitor is just like any other ignition system with a Tacho output.

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