OMG, I might have found the cause of a misfire in cylinder 1 that has been the bain of my life on and off for 3 years.
I have a 1979 sherpa van with an austin/leyland "o" series engine. The engine was new/old stock 1991 which i installed 3 years ago and have had overheating problems right from the start and eventually misfire issues.
On dismantling the cylinder head of this overhead cam engine i have found a ring of steel around the valve spring seat down in the valve assembly recess. It was on the inlet of cylinder 1 and and is non existent on any other valve assembly. (see pictures)
The ring of steel prevents the valve spring properly seating and is roughly 2mm high.
Does anybody know how or where this could have come from I guess during manufacturing and/or installation at the factory.
And Will alien component found in new engine tear down effect valve behaviour?
I'm not 1 to generate conspiracy theories but the engine does have in bold, proud lettering "E666" 
