Engine was removed, with complete rewiring done and motor was rewired into the brand new harness. Car is a negative earth vehicle and we now have no spark from the coil and on replacing the coil we now find we get a single spark from the coil through the distributor but we've used another non mini coil from a negative earthed car to get a spark. Wondering if it is because the original coil & distributor were set up in an odd way to compensate for the car having negative earth. It has electronic points in the distributor. Battery voltage while cranking is 10.8 volts. Any suggestions??

If you have checked the wiring, I suspect the electronic points...

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"Show me the Mini!"

I thought that maybe the problem... But still does not explain why I cannot get even a simple spark from the coil when I bypass the points and connect a spark plug to the lead on the coil, earth the spark plug then short the negative side of the coil to earth intermittently to simulate original mechanical points... That should produce a spark but does not? Both the distributor and coil are relatively 'new'..... Thinking there is something I've missed?

you've kinda changed too many things to be able to point at any one thing... I'd go back to the original distributor and coil and confirm that the engine will start and run, then you'll have a known starting point to move to the electronic dizzy

there shouldn't have been anything odd done to make it run with negative earth.

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did I tell you that I won a trophy?

The only thing that was done was the old wiring loom was been replaced. The coil and dizzy are the original ones that were on the motor?? A mystery.....

Just have to be systematic and change/test only one thing at a time

i would start by checking the loom at coil feed - is old one ballasted and new one not or vice versa etc
then in approximate order

1. earth strap-
2. power at coil
3. coil lead
4. Dizzy earth if required - sometimes have to scratch away some paint
4 HT leads - less than 5 ohms ( or 5000 or 5 somethings .... i can't recall)

then i would swap out parts one at a time

swap the coil out for a correct replacement
then i would check electronic points ( there is a chance that if you kept the ignition turned on for an extended period then your electronic points fried as an separate issue to say dead coil.

hope it is something simple Cheers

Oops...

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"Show me the Mini!"

I'd toss them if over 5000 ohm (5K ohms).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.