13-08-2024, 08:52 PM
Hi
In Ruby era cars with DK4's, the points are grounded via the distributor body which is solidly bolted to the dynamo housing and thence to the engine block, starter motor and then starter motor return cable back to the battery.
If you have an earlier DJ4 setup with manual advance, the distributor has to be loose enough to move. In that situation there may be a question mark over effective grounding of the points if it involves the vagaries of pieces of greased metal which may or may not touch all the time. A dedicated ground pigtail from distributor body to dynamo housing would seem like a good idea.
In both cases it's worth checking that the grounded side of the points is indeed connected to the distributor case/body via whatever internal screws are used.
I'm assuming you have a good return connection from starter motor casing/engine block to the battery ?
The coil current when points are closed is about 4 amps, and the average current with points closed about 50% of the time is about 2 Amps. So when checking whether connections are "good" we are looking for no more than about 0.1 ohms resistance, preferably less.
In Ruby era cars with DK4's, the points are grounded via the distributor body which is solidly bolted to the dynamo housing and thence to the engine block, starter motor and then starter motor return cable back to the battery.
If you have an earlier DJ4 setup with manual advance, the distributor has to be loose enough to move. In that situation there may be a question mark over effective grounding of the points if it involves the vagaries of pieces of greased metal which may or may not touch all the time. A dedicated ground pigtail from distributor body to dynamo housing would seem like a good idea.
In both cases it's worth checking that the grounded side of the points is indeed connected to the distributor case/body via whatever internal screws are used.
I'm assuming you have a good return connection from starter motor casing/engine block to the battery ?
The coil current when points are closed is about 4 amps, and the average current with points closed about 50% of the time is about 2 Amps. So when checking whether connections are "good" we are looking for no more than about 0.1 ohms resistance, preferably less.