Wiring digram for 1987 BDR? Or, where do the two wires from the coil go once inside the loom? Solved. Much ballast resistor content

[anthonym]

here's the escort pdf https://www.dropbox.com/scl/fi/722o378b08r4qt2tt5yl7/escort-mark-2.pdf?rlkey=naeherub0mqq7how0tf3x7jlx&dl=0

which will work as long as the file is there on my system - in case the link above one day fails.It might be useful posted on the club space somewhere as I can't upload it as it's 137mb. Which isn't much these days.

[anthonym]

ok so longish chat with Craig at Powerspark  01527889453 who was very patient with me not knowing much at all. 

Does my car have a ballast resistor? Yes.

Is it in-line in the ignition system? No (eventually, after looking to see where it is wired in, which is to the master switch).

What does it do? It reduces the voltage to 9v which creates a stronger spark (counter intuitive!) ; and therefore the coil has to have more something, resistance in ohms I think. If not then over time the ignition igniter (the bit inside the dizzy) will be fried by the coil. 

Corrections very welcome. https://blog.simonbbc.com/ballast-resistors-resistance-and-coils/

Given you can buy a coil together with a ballast resistor I have no idea if these are desirable or not.

https://simonbbc.com/genuine-lucas-dlb110-ballast-ignition-sports-coil-gold-with-ballast/

 

Edited July 24 by anthonym

[Miker7]

The point of the ballast resistor is to reduce the voltage seen by the coil to 9v. The system is then designed to work at 9v. The clever bit is, when you're cranking the voltage naturally drops. This can cause starting issues. If you had the ballast resistor in place it might now be 6v. However your starting circuit should have a bypass so when starting you get everything the battery can deliver to the coil. This means you're back getting 9v ish and a good spark.

Is it desirable - yes if you understand the wiring. In the escort it didn't have a physical resistor as such, it had a wire with resistance built in. Turns out you can short circuit this wire and melt it if you mess up your wiring (guess how i know!).

Edited July 24 by Miker7

[Miker7]

The resistor by your master switch *might* be the master switch resistor. Its their to damp / dump voltage from the alternator when the master switch is flicked. If its not there the power the alternator is generating has no where to go and risks damaging something. FIA master switch wiring will tell you which terminals it needs to go across & help identify if thats the purpose of that resistor.

Edited July 24 by Miker7

[anthonym]

the resistor looks just like the one for alternator dumping, I'd forgotten about that. I'm still trying to understand why less is more, maybe I'm being a bit obtuse. 

>> (guess how i know!)>> well worn path!

edit: more ballast resistor chat continues here: 

 

Edited July 25 by anthonym

[Mcalvert]

On 23/07/2024 at 18:03, anthonym said:

Sadly his book seems not available.

• It seems now that I must test my Pertronix Ignitor which involves taking the (very hard to work on) dizzy to bits and turning the engine by hand and measuring change in resistance.

specifically from a.i. 

I found this: **Signal Test**:
   - Reconfigure the multimeter to measure continuity or resistance.
   - Rotate the engine by hand so that the distributor rotor passes the magnet sleeve or trigger.
   - Observe the multimeter: you should see a switching signal as the magnet passes the sensor. A consistent change from open to closed circuit (or vice versa) indicates a functional signal.

Given I know 12 volts is going in to the Ignitor and no spark is coming out of the plug - and this immediately after switch off of a reasonably running engine.

edit: given the meter is attached at the coil end, in resistance mode, why do I need to take the dizzy cap off?

Wish I'd seen your post yesterday Anthony yesterday but I've just put a duplicate copy I have of Tony Weale's book up on Ebay!  (It's very, very useful for owners of classic Sevens).  Not attracted much interest yet if you were looking for a copy 👍 https://www.ebay.co.uk/itm/116265507834 

[SM25T]

Michael YHM

[David Mirylees]

I run an Aldon distributor (same as Petronix?) in my 1973 Lotus Europa twin cam.
This is a screen shot of the Europa wiring showing the ballast resistor wiring.
The ballast resistor used is a separate quite large item.

Don't know if this is of any help but...JIC 🤞 

[anthonym]

Thanks for that David, apologies I missed it earlier and it illustrates what my car does not have, which is the solenoid>coil connection - not to mention confirming the ballast-resisitor is a pretty large thing had to miss (assuming it's not the Ford "clever wire" version which as far as I have seen has never been used in a Caterham). 

a t b Anthony

[anthonym]

This post/entry is summarised here https://www.caterhamlotus7.club/blogs/entry/1052-bdr-wiring-ballast-resistors-and-types-lucas-43d-distributor-blanking-plate-pertronix-electronic-ignition-and-coil-covertly-damaged-dizzy-cap-no-spark/