Replacing the con-rods is no bad idea, if you have the funds. Cleaning out the sludge traps is absolutely essential and costs next to nothing. With clean sludge traps the risk of breaking rods is low. With blocked sludge traps - as most are - the risk of breaking rods is about 100%.
36 4G, 37 VH, 54 KH(A), 75 Healey 1000/4, 52/53 ex ISDT KHA (project).
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.