[Mgs] Wiring in Distributor

[PaulHunt73]

Exactly the same as before.  If you have the original coil i.e. spades 
labelled SW (SWitch or ignition supply) and CB (Contact Breaker or points) 
then some say you need to reverse that, but it's marginal.  Not only that it 
only makes a marginal difference to the spark, but by reversing it to get a 
fractionally better spark by retaining the original HT polarity, you reduce 
the auto-transformer effect which fractionally reduces it again.  Whilst it 
can make a difference to very early low voltage coil ignition systems, the 
effect on ours is minimal.  If you were really bothered about it then you 
could fit a negative earth coil i.e. one with + and - markings instead of SW 
and CB.

The order of parts on the threaded stud is:
1. Insulating washer, with the step facing upwards.
2. Points spring, seated over the step in 1.
3. Condenser and coil wires, in either order.
4. Second insulating washer, step facing down, and located in the holes in 
the condenser and coil wire terminals, and the points spring.
5. Nut.

If you still have no spark, then with the ignition on, manually open and 
close the points.

With the points open you should have 12v on both coil terminals and the 
junction of the points spring, condenser and coil wires in the distributor.

With the points closed you should still have 12v on the coil terminal that 
has the white wire on, i.e. the ignition supply, but zero volts i.e. an 
earth on the other coil terminal and the junction mention above.

If you don't have that, come back with what you do have, rather than me 
going through all the possible options you could have and the likely causes.

Bear in mind that new components, especially ignition components from many 
sources, are poor quality these days and can be faulty on receipt or fail 
very quickly.

PaulH.


----- Original Message ----- 
> On my 1966 MGB, converted to negative ground, how is the distributor
> supposed to be wired into the system?
>
> Inside the distributor, on the post provided with the points, the wire 
> from
> the condensor and the wire from the slotted post (to coil?) are joined
> together with a nut?  Right?  Any difference which is on top or bottom?