engine and drivetrain Another Coil/Ballast Resistor Question

[jpcapoc]

This may stupid, but can someone tell me what the resistance across the + and - posts on a Bosch Red Coil read?

Here's why I'm asking: I have an XR700, and I've had an intermittent ignition problem. The engine will suddenly die, somtimes it will recover within seconds, other times it takes 5 to 10 minutes to recover. It happens once a week, two weeks, not very often but very frustrating and dangerous. I read Zenon's post regarding ballast resistance, checked mine and it was 1.0. The Crane installation instructions say that a coil with ballast resistance will read 3-4 ohms across the two coil terminals. My coil read less than 2 ohms, so I concluded that my coil did not have an internal resistor and I needed a ballast resistor with higher resistance, as the Crand manual said that you need 1.4 to 1.9 ohms ballast if you don't have an internal resistor in the coil.

Furthermore, I'm thinking that I could have a potential heat problem as I mounted my Crane unit somewhat close to the headers, I'm suspecting that between the potential heat problem, and incorrect ballast one of these could be causing the ignition problem. I moved the Crane unit to the plenum, bought what I thought was a Bosch red coil, a 1.9 ohm ballast, and so far so good. The car even starts better. I bought a new coil just for the heck of it, the old one is an "Allison" and I've never heard anyone on the forum using one, and I wanted to eliminate the coil as a potential source of the problem.

Here's why I'm asking. I bought the Bosch coil from a very reputable vendor (I won't mention who just to avoid embarassing him in case he screwed up - one of his younger employees helped me) The "red" coil is actually bare metal with BLUE label and markings. The employee assured me that it was the same as the Red coil, that it's not red because it was made in Mexico (Brazil, actually). Anyway, after thinking about it, this bugged me so tonight I put the ohmmeter on it and it's 2.9 ohms! I'm thinking that this is really a Blue coil! If it is, the vendor will exchange it, but before I drive down there, I'd like to know for sure. The part number is 0 221 119 027. So if one of you guys with a red coil and an ohmmeter could check, I would appreciate it. I'm curious as to what a true blue coil reads also.

Sorry for the long winded post, just wanted to explain the situation!

Thanks!

[BillWilliams]

my meter is in the shed, I will read the resistance by days end for you.

Blue coil 2.8 ohms

Red coil 1.5 ohms The coil is silver with a red label, part number 0 221119 030 - kw 12v

[02fanatic]

The new replacement Red Coil is Silver with red Sticker like what Bill shows. I actually have both a Red Coil and the newer Silver "Red" Coil" - as my mechanic replaced the original coil with the newer Silver coil in Hugo, not knowing that I already had an unused Red Coil backup - so I'll keep that one as a spare....anyhoo, as I recollect, the Red Coil is THE coil to use with your XR700 Crane, and the external ballast resistor is 1.8 Ohms. I actually am running old stock resistors on bot of my tiis with red Coild\s..Hugo has the Crane XR700, and the '73tii has stock points. Both cars run like the perverbial "scalded dog"...man, I'm anxious for Spring and driving weather!!! :-)

Good luck,

John

[jpcapoc]

Thanks!

Got it all straightened out now. my new red coil is Red! Such a stupid thing. I never should have walked out of there with a Blue Red Coil.

Great pics Bill! that removes all doubt!

Nice collection John, I'll bet you can't wait for some good weather! do the tii's have the old .9 or 1.8 resistors? I really don't know if it makes a difference, For me, it was relatively cheap to eliminate the resistor and coil as a source of the problem. If this doesn't work, next step is to replace the XR700 unit. Troulble is, the problem was intermittent, so I won't really have confidence that it's OK for about three to four weeks, and hopefully with some hot weather in there.