resistance to coil from power

[1.9H70Gt]

how much resistance should there be?

[B-townOpeler]

I may be off by a bit but I think voltage is usually knocked down around 3 or 4 volts to ~9 volts by the resistor wire after the initial 12 volts to start.

[wrench459]

On the primary side 3 ohms.. the secondary side depends on the number of turns in the coil for the inductive kick woooo.
If you want to dig deeper into this check out the download section.
opphs I misread this post soorrry..check into the coil ramp time.Thats whats you after correct?
One coil four cylinders to fire :-(

[kwilford]

Originally Posted by B-townOpeler I may be off by a bit but I think voltage is usually knocked down to around 3 or 4 volts by the resistor wire after the initial 12 volts to start.

Right idea, wrong numbers. IIRC, the "resistor wire" (the clear insulated wire that powers the stock Opel coil) has about 1.8 ohms of resistance. Voltage at the coil +'ve terminal will depend upon current. When the coil is saturated, the current will be negligible, and the voltage will be just slightly lower than the source voltage (±14 volts). At full OEM coil current (about 3.8 amps according to the FSM), I believe that the voltage at the end of the resistor wire will be about 9 volts.

Originally Posted by wrench459 On the primary side 3 ohms.. the secondary side depends on the number of turns in the coil for the inductive kick woooo. If you want to dig deeper into this check out the download section. opphs I misread this post soorrry..check into the coil ramp time.Thats whats you after correct? One coil four cylinders to fire :-(

I am not sure about your answer regarding "coil ramp time'. However, the OEM coil is a "non-resistor" type, with 1.8 ohms internal resistance on the primary windings. The OEM resistor wire provides the required voltage reduction. If you eliminate the resistor wire (or use a Pertronix powered by the full fuse box voltage and want to use the same full voltage to power the coil), then a coil of approximately 3-4 ohms is required.

HTH

[GoinManta]

The same as a 75 Dodge Dart or most others.

ACDelco Resistor
Part No. C1102

its about $5-10

Its a pretty universal part if your changing the resistor wire out to a standard wire and still have points.

[tekenaar]

. . . did this earlier this year for my Dutch friends . . .

[wrench459]

I'm coming up with 1.4 ohms on the primary. Don't have a clue where the 3 ohm's came from other than a senior moment
As far as the current ramp of a stock Opel.Attachment 22336