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Step-by-step video workshop courses<br />
THE PROCESS<br />
Tech Tip<br />
Remember, the<br />
negative terminal<br />
will now connect to<br />
the body earth<br />
wire.<br />
1 Battery<br />
2<br />
Swap over the battery leads. Don’t connect<br />
them at this stage, but do make sure they’re long<br />
enough. The battery poles are different sizes, so<br />
you’ll have to swap over the clamps or fit new ones.<br />
Starter<br />
The starter motor will turn in the correct<br />
direction without modification. The starter solenoid<br />
should also work correctly. Likewise, a solenoid that<br />
operates a gearbox overdrive will be unaffected.<br />
3 Regulator<br />
The regulator and its<br />
wiring will also work correctly<br />
without any modification.<br />
Tech Tip<br />
Do the same<br />
if an electric<br />
radiator fan is<br />
fi t t e d .<br />
4 Ignition coil<br />
5 Electric fuel pump<br />
6<br />
Reverse the connections to the coil. This<br />
ensures the spark will still jump from the hot middle<br />
electrode of the spark plug to the cool side electrode.<br />
Fail to do this and the engine won’t start when hot.<br />
Most SU-type (ie, ‘clicking’) pumps will work<br />
regardless of polarity. Other pumps may need their<br />
wires reversing. Test the pump by briefly connecting<br />
it manually. Swap the wires over if it doesn’t work.<br />
Interior fan<br />
The interior fan will probably blow backwards,<br />
so reverse its wires. If it earths through its metal<br />
casing, you’ll have to replace it with a negative earth<br />
version. Many models were made in both polarities.<br />
Step 1<br />
Temporarily connect<br />
the battery earth.<br />
Remember it’s now<br />
negative earth!<br />
Step 2<br />
Remove the field wire (it’s the<br />
small cable, usually labelled<br />
‘DF’). Use a length of stout<br />
wire to briefly connect the<br />
DF terminal straight to the<br />
positive pole of the battery.<br />
Repeat a few times.<br />
Reconnect the field wire.<br />
7<br />
Repolarise the dynamo<br />
8<br />
Dash gauges<br />
Most gauges are of the thermal type and will<br />
be unaffected. If an ammeter is fitted, reverse the<br />
connections on the back. An electronic tachometer<br />
will need to be replaced with a negative earth type. ■<br />
To subscribe to <strong>PC</strong> go to www.greatmagazines.co.uk/practicalclassics<br />
PRACTICAL CLASSICS // DECEMBER 2015 129
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