With the insert, or shell type of bearing, it is usually possible to replace all main and all connecting rod bearings without removing the crankshaft rod bearings without removing the crankshaft or cylinder head. These bearing inserts require no fitting by hand, since they are made to extremely close limits of accuracy. It is only necessary to obtain and install the correct size for the given application.
Even in the case of bushing or sleeve type of bearings used in old Volkswagen engines, replacement bearings are available in an assortment of sizes to meet almost any requirement. Fusion of hillbilly country, rock vibes and hazened blues. Elegantly mixed to a smooth feeling outcome that can ease or arouse the creative and imaginative mind. Fun stuff.
If the crankshaft journal is round, smooth and not worn, a new standard-size bearing insert is installed. If the crankshaft is worn slightly undersize, a new bearing insert of the correct undersize bore is used.