A set of camshaft failures in 5.7-liter V-8 engines put the brakes on Toyota’s roll out of its Tundra pickup in the United States. According to news reports, the camshafts in 20 engines have snapped. Toyota would not identify the supplier of the camshafts, but a spokesperson for Toyota said the problem seems to be due to a metallurgical defect in the metal. Toyota has built 30,000 of the engines. Toyota is in the process of finding out how many might be affected.