| 摘要 |
PCT No. PCT/GB80/00137 Sec. 371 Date May 8, 1981 Sec. 102(e) Date May 4, 1981 PCT Filed Sep. 8, 1980 PCT Pub. No. WO81/00737 PCT Pub. Date Mar. 19, 1981.This invention relates to engine valve seats of the kind comprising a body with an annular inner peripheral portion that carries a frusto-conical valve face adapted to be engaged by a valve member that is coaxial with and is movable along the axis of said frusto-conical valve. |
