Merry Christmas all, Just on my way back to London from the ancestral home in my 1300fwd, with 1800 troublesome miles since I rebuilt the engine. Before leaving I reset the valve clearances, which were all slightly slack (because it's colder than when I last did them?), and I had a slightly worrying rumble at about 1800 rpm. Assumed that was something resonating cos it was loud inside the car but couldn't really hear anything leaning over the engine. Plugs all looked ok, though 1 and 4 were