SHANGHAI, June 18 (Reuters) - China stocks ended flat on Friday, while posting their third straight weekly drop on worries over lofty valuations and Sino-West tensions. ** The blue-chip CSI300 index was unchanged at 5,102.47, while the Shanghai Composite Index was also flat at 3,525.10. ** But for the week, CSI300 slumped 2.3% and SSEC lost 1.8%, both posting their third week of losses in a row. ** Shares in China’s new energy vehicle-related companies jumped, with the CSI new energy vehicles index ending up 4.6%, helped by upbeat sales estimate. ** China’s new energy vehicle (NEV) sales are expected to grow more than 40% each year in the next five years, a senior official at the China Association of Automobile Manufacturers (CAAM) said. ** Analysts and traders said lofty valuations of some high-flying sectors, including new energy, healthcare and consumer firms, became a focal point of concern for investors, given a lack of upside momentum. ** Market participants were worried about an end to easy monetary policy as data pointed to a quick recovery in overseas economies, which could weigh on stocks with frothy valuations, said Hu Yunlong, a Beijing-based hedge fund manager. ** The U.S. Federal Reserve on Wednesday began closing the door on its pandemic-driven monetary policy as officials projected an accelerated timetable for interest rate increases. ** Adding to the pressure for the week were tensions between Beijing and the West. ** China denounced on Monday a joint statement by the Group of Seven leaders that had scolded Beijing over a range of issues as a gross interference in the country’s internal affairs. ** Bucking the broad weakness, tech stocks shined in the week on signs of more policy support from Beijing. ** Shanghai’s tech-focused STAR50 index tracking the STAR Market added 1.4%, posting its sixth weekly gains. (Reporting by Luoyan Liu and Andrew Galbraith; Editing by Rashmi Aich) Our Standards: The Thomson Reuters Trust Principles.