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2barrelpower
Sitting Bull

USA
135 Posts

Posted - 10 May 2015 :  4:05:07 PM  Show Profile  Reply with Quote
I'm running a points style ignition with a Crane XRi and a PS20 coil.

I am getting 12.4 V to the + side of the coil. Should I be running a ballast?

I am running a .40 gap.

I was digging around on firstgenfirebird and read this:
http://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=196521

Earlybird is recommending .50 with R45s.

What should I set my gap to?

69FB, 350P, 9 to 1, Comp 260H, Stock Valve Train, Performer Intake, 1406 Carb, Hooker Headers, Points Style, Crane XRI, Crane PS20, TH350, stock stall, 3.08 gear, and 235/60/15 Firestones.

cortcomp
Coyote

USA
5338 Posts

Posted - 12 May 2015 :  08:58:57 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I'd think no ballast with that setup, and .40 or .50, probably notice no difference?
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2barrelpower
Sitting Bull

USA
135 Posts

Posted - 12 May 2015 :  11:44:15 AM  Show Profile  Reply with Quote
Cort, so what you're saying is that there are no real gains to be had by having the gap wider.

69FB, 350P, 9 to 1, Comp 260H, Stock Valve Train, Performer Intake, 1406 Carb, Hooker Headers, Points Style, Crane XRI, Crane PS20, TH350, stock stall, 3.08 gear, and 235/60/15 Firestones.
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 12 May 2015 :  12:42:51 PM  Show Profile  Reply with Quote
I always though with the low power of points that you want it at .35. With HEI, I usually ran them at .45. The factory set HEI at .60 for emission crap. Closing them down gave a better burn. Again, wasn't the factory spec for points .35?
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cortcomp
Coyote

USA
5338 Posts

Posted - 12 May 2015 :  4:12:02 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I think there's probably some gain from going from .35 to .45, sure, if the ignition can handle it and it's not burning very well. But i doubt any difference from .40 to .50, (or slightly worse if the ignition can't jump the .50 as well.) Being that the XRi is like a pertronix, i'd say .40 is right. You're not as hot as HEI to go to .50, but you're better than points at .35 to .40. Try .40, leave the power to it at 12v and drive it. (the instructions will tell you if they want less, i doubt they want less than 12).

If it runs ok, done. It's not like moving the plug gap .10 on a lower compression motor that's not fighting the spark jump is going to make any noticeable difference, i bet even on the dyno.
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2barrelpower
Sitting Bull

USA
135 Posts

Posted - 12 May 2015 :  8:26:55 PM  Show Profile  Reply with Quote
I've got a miss at idle, which could be a number of things, but I'm going to squeeze the gap down to .35 and see if that clears it up. Like you said, experimenting with it incrementally is probably the right thing to do.

69FB, 350P, 9 to 1, Comp 260H, Stock Valve Train, Performer Intake, 1406 Carb, Hooker Headers, Points Style, Crane XRI, Crane PS20, TH350, stock stall, 3.08 gear, and 235/60/15 Firestones.
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