antofa123: Blown head gasket isn't too bad... at least you won't have to strip the block down. Good luck with the rebuild!
antofa123: Mine doesn't have that ringing knock....
fillyerboots1: That tapping sound could just mean the tappets need adjusting, but I'd be interested to know what conclusion you came to, and if you still have this engine. Mine is a 2 year-old 1GM10 which sounds a bit like this upon first start up until the oil gets around the system and it warms up a bit, when it thumps rather than 'taps'..
dieselsailor9: That knocking is not normal. It is a mechanical knocking so likely internal. I believe you will find metal sediment in the oil unless the oil has been recently changed. This is an old Yanmar model, the repair will likely be more than the engine is worth. Your will probably need to get the engine out to break it down and begin determining the cause; at that point I would suggest repowering with a newer engine rather than rebuilding this 35 year old engine.
turbo5er: Does the engine go low as 4:50 for a long time without stopping? Mine does not go that low.
sailpunk: This does not sound right, the loud knocking is not normal. I have a YSE8 in good working order and that is not how it is supposed to sound. The last comment is likely right however make sure it is not something rattling on the engine. Check the mechanical oil filter for metal.
MrAndrewee: sounds like the piston is hitting the the top. Maybe you need to inspect the engine oil and look if there are parts or dus of iron in it. If so, then ask professional advice, maybe the engine needs to be revised.
sixtyfiveford: Sounds like an air cooled diesel to me. Is it still going strong?
101lumix: sounds the same as mine!
Neil Deverell: great!!!!!!!!!!!!