Coil Question

[Zed Head]

If he has current-limiting seems like he'd get best performance from a lower resistance coil.  Even their instructions would leave him with a 0.84 to 1.2 ohm coil if he was retrofitting a stock 1978 280Z.  Just saying.  Instructions are vague, they just say "remove ballast resistor".  No coil specs given.

[Zed Head]

42 minutes ago, 7tooZ said:

About 3 blks from home it simply died. Turned over but wouldnt start. By the time i went back to get it (couple hours +/-) it started and ran rough (like the plugs were fouled) for 10-15 sec and then was fine.

This sounds more like an ignition module problem.  For future reference.  If you put a meter in your car you can check the coil primary circuit if it happens again.  Good luck.

[SteveJ]

On 7/4/2021 at 3:19 PM, Zed Head said:

If he has current-limiting seems like he'd get best performance from a lower resistance coil.  Even their instructions would leave him with a 0.84 to 1.2 ohm coil if he was retrofitting a stock 1978 280Z.  Just saying.  Instructions are vague, they just say "remove ballast resistor".  No coil specs given.

I was worried about the tach performance with a 1 ohm coil. This morning I installed a Pertronix with a 1 ohm coil into a car and bypassed the ballast. The tachometer appeared to be functioning correctly.

@7tooZ - You could go with a Pertronix 1.5 ohm coil (40011 or 40111) or MSD 82023 coil. It looks like you can bypass the ballast resistor with no ill effects, too.

[7tooZ]

19 hours ago, SteveJ said:

I was worried about the tach performance with a 1 ohm coil. This morning I installed a Pertronix with a 1 ohm coil into a car and bypassed the ballast. The tachometer appeared to be functioning correctly.

@7tooZ - You could go with a Pertronix 1.5 ohm coil (40011 or 40111) or MSD 82023 coil. It looks like you can bypass the ballast resistor with no ill effects, too.

I have a PerTronix 40611 arriving today. Drove the car yesterday on two 10 mile trips with no issues. Are you suggesting the 1.5 ohm would be preferred over 3 ohm?

[SteveJ]

2 minutes ago, 7tooZ said:

I have a PerTronix 40611 arriving today. Drove the car yesterday on two 10 mile trips with no issues. Are you suggesting the 1.5 ohm would be preferred over 3 ohm?

You might see better performance with the 1.5, but the 3 should work. The spark may be a little weaker. 

[7tooZ]

40111 is the epoxy 1.5 ohm. Thanks I order it to.

[Zed Head]

MSA suggests a 0.4 ohm coil.  Not sure if it's a good idea or not but it's what they do.  The GM HEI module, which probably has the same general current control technology, uses a 0.6 ohm coil.

Just filling out the story.

https://www.thezstore.com/page/TZS/PROD/12-4006

https://www.summitracing.com/parts/fst-730-0060

 

[SteveJ]

I would not use a 0.4 ohm coil unless you are keeping the ballast resistor. I wouldn't go below 1 ohm unless you are keeping the ballast resistor.

I was suggesting the 3 ohm down to 1 ohm since it sounded like @7tooZwas planning on jumpering out the resistor. Using a 0.6 ohm coil with no resistor would mean about 20A current through a 14 gauge wire.

[7tooZ]

4 minutes ago, SteveJ said:

I would not use a 0.4 ohm coil unless you are keeping the ballast resistor. I wouldn't go below 1 ohm unless you are keeping the ballast resistor.

I was suggesting the 3 ohm down to 1 ohm since it sounded like @7tooZwas planning on jumpering out the resistor. Using a 0.6 ohm coil with no resistor would mean about 20A current through a 14 gauge wire.

Good advise thanks. FYI i have been using the XR3000 for quite awhile  10+ yrs without the resister. The process of illumination lead me to maybe the Coil so Ill replace it and make no other changes and seen if it shows up again. The 1.5 ohm will ne here Saturday, 

[SteveJ]

If it's not the coil, consider going from the Crane to the Pertronix. It's stupid simple to install the Pertronix.

[Zed Head]

27 minutes ago, SteveJ said:

Using a 0.6 ohm coil with no resistor would mean about 20A current through a 14 gauge wire.

Good point.  It would just be a quick blast though, right, then it would fall off?  That's the whole thing with current control.  I wired my HEI module up in the engine bay and used appropriate wires.  Something to consider for people retrofitting a module in the old ignition module cases, as EuroDat's instructions show.  That's a long run for small wires.

Not picking on the XR3000 but I think that it is basically a small module in a big box.  I'll bet if you took it apart there would be just a small circuit board inside.  

The other possible failure point would be the trigger mechanism, which is the other sophisticated piece of technology.