The really sad thing is that I put it back together this afternoon with new big ends and some better con rods and it still sounds the same.
Back to the drawing board.
Would the very clever BBs sort it?
Drives a Smart Cdi - 65 to 85 MPG
Probably, in the right place but finding where they are needed is proving difficult.
You would think that an engine design that reaches its hundredth birthday in 2021 and that has been in the current form since the late 1950s would have suffered every knock shake rattle and buzz that it could possibly make but everywhere I ask this knock is a new one.
Did you check big end clearance (e.g. plastigauge)? Perhaps you have a reground crank and standard size bearings...
Took STD out and put STD in. Didn't bother measuring the crank, that is not so easy to do.
It ran fine until I red lined it anyway so STD must have been correct.
Stretched big end bolts?
Hmmmm..... that sort of sudden flat sound at 16seconds .......
Does it still have full power ?
You're so money supermarket and you don't even know it!
broken crank shaft?
broken push rods?
broken cam shaft?
broken flywheel bolts?
Definitely sounds like a full engine strip down is required.
John