After Snetterton we decided to remove and refresh the engine due to lower than ideal oil pressure. Nothing wrong was found – perhaps it was just fuel diluting the oil with the bodged air intake system blocking on cylinder 1 – so it was rebuilt and prepared for refitting.

It was then that Martin discovered the missing teeth on the oil pump drive belt.  Failure analysis is still ongoing as I write this, but will update this post when we’ve deduced the cause.

Click on the thumbnail to the right to see the belt, and here to read about belt failure modes.