Honda hollow crankshaft.
Starting in 2004 a Honda program produced a V10 crank in which the 34mm pins had a 6mm wall thickness. The jointing process was friction-welding. 5-pieces were preheated and forced together in turn (rotating x stationary) at 1900rpm under a 10 tonne load. The joint strength was equal to the base material. The interior passage was cleaned to be suitable for oil-flow by barrel-finishing. The crank mass for the intended 2005 application (3-litre V10) with added tungsten counter weights, was reduced by 7.8% from 10.6kg for the solid assemble to 9.5kg.
“Cosworth have also tried a welded crank TJV10”. Cosworth did toyed with a welded-up crank, but they decided that the welds could not be sufficiently crack tested. This toyed with process was intended to hollow-up the crank and not intended for the use of a roller bearing crankshaft. A build-up crankshaft for roller bearing use, the bearings are assembled on the journals before the parts are build-up. Welding the crank-journals at their respective centers cannot be done with the bearing on the journal, and that is besides the welded-up journal having to be machined finished after welding. Peugeot V10 was the last F1 engine to use a roller bearing crankshaft. They used a one piece crank with normal split big-end and main caps with split roller gauges and outer races with the rollers running directly on the crank material.