The MGB GT V8 wiring loom is unique to the V8, loom number VL601 for chrome-bumper specification, VL602 for rubber-bumper specification. The loom is built specifically for the V8 from manufacture, with routings, connector positions and circuit specifications matched to the V8 electrical components. The V8 loom is not interchangeable with any four-cylinder MGB loom, connector positions, wire colours, circuit identifications and overall layout differ.
Loom Routing
The loom routes from the bulkhead-mounted fusebox to all electrical components on the car. Engine-bay sections feed the alternator, starter motor, distributor, ignition coil, sender units and lights. Dashboard sections feed the instrument binnacle, switches and dashboard lights. Lighting circuits route to the front and rear lamp clusters, with branch circuits at each lamp connection.
Rear-end loops feed the rear lights, fuel tank sender, reverse light switch and number plate lamps.
Loom Construction
The original loom uses PVC-insulated wires bound together with cotton braid or PVC tape. Wire colours follow the standard British classic-vehicle colour code (red and white for indicator wires, red and green for tail lights, and so on), with specific colour combinations identifying each circuit's function.
Replacement looms are available reproducing the original colour code and routings.
Loom Service
Looms suffer from age, insulation hardens and cracks, exposing copper conductors that can short to chassis or to other circuits. Connector blocks oxidise, causing intermittent operation. Splices made during the car's life can degrade. Loom replacement during a major restoration is significant work but provides reliable electrical operation for many years afterwards.
Spot repair is appropriate for localised damage where the rest of the loom is sound.
Specification Choice
The correct loom for the car must be ordered, VL601 for chrome-bumper V8s, VL602 for rubber-bumper V8s. The two looms differ in routings around the front of the car (bumper-area lamp installations differ) and in some circuit configurations. Fitting the wrong loom causes major fitment problems.
MGOC Spares
MGOC Spares supplies V8-specific wiring looms (VL601 chrome-bumper, VL602 rubber-bumper) and loom service components for the MGB GT V8.