Rewiring later style car for electronic ignition

[Nilfisken]

Hi,
trying to follow a few older threads about putting electronic ignition into later style vehicles but not sure if I get it all right so posting a new thread with a few very specific questions. Maybe they can help a few others too as a general synthesis?

Situation:
UK Spitfire 1978 with what appears to be a absolutely untouched wiring, spent whole sunday checking all visible wires and except a few replaced wires in the engine bay everything else appears bone stock, all colour codes appear correct. Coil is changed though for a 12V ballast (Part nr. 09-202) instead of the specified 6 volt ballast? I bought the standard ebay kit from Simon BBC but added the 'red rotor' and a standard 12V coil (Part nr. 09-201).

Question 1: Am I right in believing that circuits that get power in the normal 'ignition on' key position are still fed during the 'starting position'?
Question 2: To bypass the resistor wire without having to remove the original wiring could I just remove it from the coil and attach a new 12V feed the coil + terminal with wire drawn from the fused side of the circuits being active in the normal ignition on position (such as gauges)?
Question 3: Should I retain the wire going from the starter solenoid to the coil that normally feed the coil during cranking or is that one unnecessary with the resistor wire now bypassed (or is it big drop in voltage in the normal circuits during cranking making it better to keep it attached?
Question 4: Is it smart to open up the plug gap a bit with the electronic ignition added or does that require even hotter ignition systems? If opening up is recommended how much would be a good ball park figure?

Cheers!

[Bainzy]

1) it doesn't affect those parts of the circuit at all
3) with the electronic ignition you have an extra wire going to the coil, now that the distributor has red and black wires coming out of it. apart from removing a ballast wire if you have to, you shouldn't change anything else
4) try it standard first, then have a go with 30 thou.

[lancepar]

Dizzy wiring (four cylinder Accuspark example for neg' earth cars with Delco dizzy).
I would recommend getting the engine running on the points system first.
Remove cap and rotor.
The original wire from the - (Neg') side of the coil is removed along with the condenser and points.
The electronic unit is secured in the dizzy using the condenser screw and points screw with smear of supplied paste between the mating surfaces.
The plastic ring with the magnet in fits over the rotor lobes and the rotor arm on top of this where it used to be.
The two wires fed through the dizzy grommet are red and black, black goes to the - (neg) side of the coil and the red wire to the + (Positive) side of the coil which is fed from the ignition circuit.
Cap back on.
Start car and adjust timing, but engine should start and run if dizzy has not been rotated/moved from original position.
If done like this, it should work,
Note: instructions say black wire may be blue, but whatever, it goes to the low tension - (neg) terminal.

8)

[CharlieB]

3182 wrote:

Question 2: To bypass the resistor wire without having to remove the original wiring could I just remove it from the coil and attach a new 12V feed the coil + terminal with wire drawn from the fused side of the circuits being active in the normal ignition on position (such as gauges)?

Yes, you do need this extra feed if bypassing the ballast resistor.

1381 wrote:

3) ..... apart from removing a ballast wire if you have to, you shouldn't change anything else

except adding the 12v feed

[Bainzy]

CharlieB wrote:

except adding the 12v feed

He shouldn't need to add a new feed, just trace the Pink/white wire to its end, remove it and connect what is left to the coil. If the entire wiring loom is factory original, no sense making it more complicated now.

[Nilfisken]

Hi,
thanks for the inputs. I think it will be fairly straightforward now. I think the easiest solution for the 12 volt feed during normal ignition position (not cranking) is best sorted by a brand new wire drawn straight from the fuse box. By doing that I can just disconnect the resistor wire and still leave it residing in the car. The resistor wire seems to be deeply imbedded in the wiring loom and more harm trying to remove it than just leaving it but unused. As I read the schematics I still need a new 12v feed since the wire from the starter solenoid will only be feeding the coil while the starter motor is running. Guess last question not fully resolved issue is whether I might as well remove that one or not, if the voltage in the normal circuits don't drop to much during cranking I don't see any reason for it at all after bypassing the resistor. ON the other hand it can't do any harm being left in place.

Car is running pretty OK at the moment so I know the present wiring is fine, but since I will be putting in a standard coil the system needs to be without the resistor.

Thanks everyone! I get back with a status report as soon as the operation is done!

Cheers

[Darren Sharp]

I have just done this job on a 79 1500 with an accuspark kit. No problems just followed the instructions on the Kit. Only problem was that kit was only supplied with the + (Red) Cable and I had to make up the earth lead. There was no reference to the Ballast resistor wires in the kit for a 45D distributor so no problems.

Sage advice :  Just stick the points and condensor down the back of the Battery in case of failure!

Darren

[Nilfisken]

Operation successfully completed!

I decided to do this rewiring as undestructive as possible so started the morning looking for a wire that was easy to use for feeding the coil so that I only had to unplug the resistor wire, not fully remove it. After checking the fuse block connections itself (they were all stock and it felt sad to cut into one of them) I decided to borrow some current from the back up switch. This circuit is only active when ignition is on and it is on the fused side of the wiring so it seemed perfect. Even better is that it was easy to reach as it leaves a taped up part of the main wiring loom just next to the fuel pump where two wire branched of to the back up switch. I replaced an old bullet style connector on the line (not sure if it was original or if it was made when replacing a gear-box(?)) and replaced it with a dual connector. Then it was only to make a small extra wire from the split up to the coil and then remove the resistor wire (White/Pink colour) from the connection to the coil only retaining the one that comes directly from the starter solenoid.

New coil was installed and then the distributor got it's share of the new parts:


Old points before removing, why do people insist on using wrong sized screw drivers over and over and over again...


Module all greased up and ready to be attached


Done!

All done I turned the key, and not a spark... Problem was very simple though, the ring around the point cam that sits beneath the rotor was to far down to get a good function. I removed the rotor and pulled the ring up and then let the rotor push it down during refitting, gave it a new turn of the key and it started right away. Ignition timing dropped some 10-15 degrees but after setting it to 10 BDC it ran better than ever. It was very clear when setting the timing how much more stable the ignition was, with points the time mark jumped back and forth when checking but with the new module it was very stable.

Car performed brilliantly on a 60 miles test run and home safe only thing noted was that the spark plugs for the rear cylinders were a bit to sooty so will have to adjust the mixture of the rear carb. Not sure how subjective it is but it really felt like the engine is running much smoother after changing out the points.

Cheers