Properly set ignition timing on a Triumph TR6 is crucial to the correct running of the engine. If the timing is off, the engine will not run its best and performance will suffer as a consequence. As opposed to some cars, the timing on a TR6’s 2.5-litre straight-6 engine can be set when the engine is not running with the use of a lamp wired to the distributor and a few tools.
Disconnect the low-tension lead that goes from the distributor to the coil. The coil will be bolted to the engine block to the left of the distributor.
Wire a 12-volt lamp on one end to the distributor where the low-tension lead was disconnected and to the battery on the other end.
Place a wrench on the crank bolt located on the end of the crankshaft pulley, just in front of the cooling fan. Turn the pulley clockwise (when looking at the fan from the front of the engine) so that the small indicator hole drilled in the back of the pulley is exactly 3/8-inch to the left of the timing pointer. The timing pointer is fastened to the timing chain cover and points down over the crankshaft pulley. NOTE: Do not turn the pulley counter clockwise as this may damage the timing chain and may result in an incorrect reading. Move the fan and pulley in a smooth, continuous motion.
Loosen the clamp located at the base of a distributor with a ½-inch (13-mm) wrench just enough so that you can turn the distributor on its base. Slowly turn the distributor counter clockwise just until the light on the lamp comes on. This should be the exact point of ignition. Turn the distributor back just enough so that the light goes out.
Tighten the distributor at this point. If the light comes back on while tightening the clamp, adjust the distributor until the light just goes out and retighten it. Disconnect the lamp from the distributor and the battery. Reconnect the low-tension lead to the coil and the distributor.