[Mgs] Distributor woes

[Paul Hunt]

On a 25D4 the coil wire from the harness is white with a black stripe 
and is external to the distributor and connects to a spade terminal on 
the outside of the distributor.  Internally there is a brown 
cloth-covered tinsel strand wire from the spade that sits under an 
insulator and nut on the points.  It needs to be electrically isolated 
from both nut and stud.

Whilst on the 45D4 it is black, is the coil wire and does pass through 
the distributor body, it is factory-attached to the and is the live side 
not the earth.  It has a tab that slides under a folded over section of 
the points spring, there is no nut, just an insulator that sits between 
the spring and a support.  A short length of wire is external ending in  
male spade connector connecting to the white/black harness wire.

Originally the 25D4 had an earth wire spot-welded and riveted to the 
points plate, 45D4 used a through-hole terminal under the condenser 
screw so that screw needs to be long enough to hold both securely.  But 
make sure neither points nor condenser screw are too long or they can 
foul the weights and cause running problems. Like the 25D4 internal coil 
connection the earth wire was originally a very flexible brown cloth 
insulated tinsel-stranded wire going to one of the screws securing the 
fixed part of the points plate to the distributor body.  Not generally 
available, if they (both coil and earth wires) fail standard wire 
probably won't last very long as the points plate is continually 
twisting back and fore as the throttle is opened and closed - if you 
have vacuum advance.

Unless you are replacing the screw that came out make sure it will fit 
before putting the condenser in position.

On 28/12/2025 12:50, Douglas Shook wrote:
>
> Question #2
> No, the black wire is the feed to the coil and needs to be under the 
> nut on the points spring. It should contact the spring but not the 
> stud. Ensure that you have a good insulator on that post/stud to 
> separate the spring from the stud.
>
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