Here’s a few pointers on flushing the block on the 3Litre Triumph V8 engine.
These engines had a bad reputation for overheating, sand left in the water galleries from casting and lack of anti-freeze in the coolant mix led to corrosion between the multitude of metals making up the engine, including steel and Aluminium.
This mixture caused a build-up of Verdigris in the radiator restricting water flow and causing the aluminium cylinder heads to over heat and warp. Heads were skimmed and replaced, without the radiator or blocks being flushed out resulting in a repeat of the process. This engine was treated with Nulon rad flush, and the3/4 AF drain plugs removed from each side of the block water jacket and the contents drained after agitating the left-hand block with a coat hanger to clear compacted debris in the drain hole area.
Next the thermostat was removed and a 3”4 to 1” BSP tap thread adjuster was machined down to allow the male insert provide a tight fit in the water hose. One plug was also replaced in the block and the top radiator pipe was blanked off to increase pressure in the flush, the plugs were then swopped to repeat the process. Lastly the radiator was removed for re coring with one of Tony Harts super-grill cores and the flush process was repeated with the bottom hose.