The Triumph V8 was a 3.0L SOHC twin-carb motor made from 1971 to 1977. And just knowing that info, you’d assume it’s pretty cool. But the Triumph V8 was riddled with designed-in faults so cad that it shouldn’t have left the factory.
Our story starts with the Triumph SOHC I4 motor found in the Dolomite. A happy, revvy, and peppy engine, it was available in sizes ranging between 1.2 and 1.7 liters. So when Triumph decided that their old 2.5L I6 wouldn’t cut it in their sleek new Stag, they decided to make their own V8 by mashing two I4's together.
The Triumph I4 was actually designed with “twinning” in mind so it wasn’t a completely outrageous concept. The trouble was the execution. The trouble began immediately. Early prototypes were 2.5L V8s topped with Bosch mechanical fuel injection. The injection couldn’t be made to work properly so it was abandoned in favor of two Stromberg carburetors. (Collectively attached by a single bolt to the intake) The carbs were reliable but didn’t make as much power as the injected version so displacement had to be increased.
They increased the displacement by expanding the cylinder bores which choked the water passages and made them smaller. They now had a larger engine with less cooling capacity.
Other bits of design brilliance include a water pump mounted on top of the engine, a coolant fill cap that was not at the highest point of the cooling system, a single row timing chain that needed to be replaced every 25,000 miles and more.
But the crown jewel of the Triumph V8 were its head studs mounted at an angle to each other that promoted head warpage. The list goes on. I wrote a super nerdy article on Driving.ca if you want more detail.
Has a worse engine ever been made?