Gunson has been the established UK brand for classic-car tuning and timing equipment for decades. The product range is built around the realities of classic-engine service work, the assumption that the engine has carburettors, points ignition, and the mechanical systems that need accurate setup to run cleanly. Each tool in the range solves a specific tuning problem with a directness that the modern OBD-diagnostic-led tools cannot match.
Advanced Xenon Timing Light
The Gunson Advanced Xenon Timing Light is the classic-car ignition timing tool, a stroboscopic timing light, powered from the car battery, that flashes in time with the spark plug firing so the timing mark on the crankshaft pulley or flywheel can be seen as a static reference against the timing pointer on the timing cover or bell housing. The Xenon Timing Light combines the strobe with a digital tachometer reading engine rpm from the same pickup, and an advance-angle dial that allows the actual ignition advance to be measured at any engine speed. For setting static timing, dynamic timing, and the full advance curve through the rev range, the Xenon Timing Light is the standard tool. The strobe pickup clamps to the spark plug lead, typically the number-one cylinder lead, and the rest follows from the tool's display.
ColorTune, The Combustion Viewer
The Gunson ColorTune is a spark-plug-shaped tool with a transparent body that allows the colour of the combustion flame inside the cylinder to be seen directly. The tool replaces a spark plug for the duration of the test, and the colour of the flame indicates the air-fuel mixture in the cylinder, blue for stoichiometric (correct), orange or yellow for rich, dark blue or invisible for lean. The ColorTune is the standard tool for setting SU and Stromberg carburettor mixture by direct observation rather than by guesswork or by feel, the carburettor mixture screw is adjusted while watching the flame, and the right mixture is set when the flame is the right colour.
For owners running multiple-carburettor setups, the ColorTune is moved between cylinders to confirm balance across the carburettors.
Eezibleed, Carbalancer, Gastester and Hi-Gauge
The Eezibleed brake-bleeding kit is the Gunson pressure-bleeder, a sealed cap that fits over the master-cylinder reservoir and is pressurised from the spare wheel through a flexible hose. The pressure in the spare wheel pushes the old fluid through to each bleed nipple, allowing a one-person bleed without operating the brake pedal. The Carbalancer is the Gunson airflow meter used to equalise the intake airflow across each carburettor on a twin- or triple-carburettor setup, held over the intake mouth of each carburettor in turn, the gauge reads the airflow and allows the throttle linkage to be adjusted until every carburettor draws the same. The Gastester is a manual exhaust-gas analyser, a chemical-reaction analyser that gives a reading of the CO content of the exhaust gas, used to confirm carburettor mixture under load.
The Hi-Gauge cylinder-leakdown tester is the diagnostic tool for assessing engine condition without dismantling, compressed air is fed into each cylinder at top-dead-centre on the compression stroke, and the percentage leakdown indicates the condition of the piston rings, valves and head gasket.