enter image description hereOMG, 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" enter image description here

  • 1
    So I understand, the main part of what we are looking at is the valve seat. What your question is about is the ring of metal kind of askew round the middle part ... is that accurate? Dec 1, 2023 at 12:58
  • @paulsteer2 yes, if you expand photo you can see more cleary the 3/4 ring ill fitting around the valve seat. SE would only allow me to upload 1 photo for some reason. I have others.oh! It alliwed me to edit in another photo. Dec 1, 2023 at 13:03
  • While this ring seems out of place for being on just one valve seat, I'm doubtful this alone would have caused your issues of overheating and misfire. Dec 1, 2023 at 13:07
  • @paulsteer im not so sure. The ring interferes with the spring seating. This would have the effect of inlet valve being pushed up max 2mm throughout opening/closing cycle. The inlet valves normally opens only i 8/9mm i think. Maybe this fuel mixture restriction could cause the misfire and then a corresponding overheating issue. I dont quite understand how a misfire can lead to overheating as i have read. What do you think? Dec 1, 2023 at 13:26
  • If the ring was actually pushing up on the spring, it's not going to affect valve travel, it's going to affect spring pressure. This would make it harder on the camshaft and other parts above the spring, but as long as there's no damage to the cam lobe, it will continue to open the valve the desired distance. Dec 1, 2023 at 14:11


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