Fireball XR700 install questions

[okartguy]

I'm in the process of converting the ignition in my '76 to a Fireball XR700. This is a system that came with a parts car I bought a couple years ago, and luckily the instructions are included. However, they cover a LOT of material, and I'm trying to distill out what I really need to know.

First of all, the dizzy appears to be new, and is marked "0 231 115 048" and "JFUR 4," with a disabled vacuum advance. The one currently installed on my car appears to be an 050 with no provision for VA. Are these two compatible?

Secondly, I'm having a hard time figuring out whether I actually need to use an external ballast with this system. As of now, I've installed the Crane Fireball PS20 coil, since the old Bosch unit was pretty beat. The instructions say when replacing a Bosch "blue" coil and still running points (which I am as of right now), to use the external ballast. The problem is, the old coil had been partially painted and had no label, so I don't know if it was a blue coil or not.

So, figuring "better safe than sorry" I went ahead and installed the ballast, and the car fires up and run great. The ballast gets pretty warm after a few minutes of running, however. Is this something I should worry about? And are you guys who have done the full XR install using ballasts as well?

Sorry for all the questions, but I'd rather not set my car on fire if I can help it! TIA-

JJ

[Tiger75]

My advice - call Crane . Their help line is great

[heinrich]

I'm 90% sure the PS20 isn't internally resisted, so you will need to keep the ballast resistor. If you check the resistance accross the terminals of the coil it should be around 1.5 ohm (plus 1.5ohm resistance from the ballast resistor = 3.0ohm total, which is what the XR700 needs). The resistor is absorbing the energy from the line, so it's going to get warm--that's what the little heat sink is for.

I'm running the XR700 with a Pertronix coil and have retained the ballast resistor. It's been running fine like that for about 6 months.

[Paul7002]

(nt)

[bret2002]

dude i love that birds quote where you list your cars! that song is one of my all time favorites. it also helps its in one of my altime favorite movies EASY RIDER!

[okartguy]

Yup... I'm a big "Easy Rider" fan myself. Plus, that line has always seemed to sum up my... ahem... "eclectic" taste in vehicles.

[jpcapoc]

See the attached post. Bill Williams shows the resistance on an ohmmeter. I was running the stock 1.0 ohm resistor, and now replaced it with a 1.9. I haven't had a problem for about three weeks. If you don't have sufficient ballast resistance, you may have intermittent problems. I still don' t know if that was my problem, but all is good now!

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,270062/highlight,/

Also see Zenon's response on the attached post.

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,269556/highlight,/