The spec sheets of a lot of modern engines contain this item claiming light weight. strength accuracy in machining.. Initial thoughts would lead to a solid conrod as in the enfield bullet which woud lead to a fantasticaly expensive built up crankshaft especially for a V 8 .It's obviously got something to do with how the rod is manufactured and the cap fitted . Has any one seen one ? :

Apparently Corus Steel makers had something to do with the design of nutless conrods . They make a con rod in a solid forging ,drill and tap the bolt holes. Then laser scribe across the big end cap .The big end eye is put on an expanding mandrill and it is forced apart . Like a piece of glass it cracks along the scribe lines and fractures with the result the cap and rod have identical faces and will unlike a machined faces always fit exactly . Usually the bolts are of different diameter so assembly it is pretty fool proof .Have I got it right ?