Abstract: A valve operating mechanism for a reciprocating internal combustion engine. The mechanism comprises a valve lifter made of fiber reinforced plastic and including a cylindrical section. A partition section is integrally connected to the cylindrical section and located perpendicular to the axis of the cylindrical section. The partition section has a lower side at which an end portion of the valve stem of an intake or exhaust valve is to be pushed. At least one coaxial annular shim engagement projection is formed at the upper side of the valve lifter partition section. Each projection is formed with coaxial two shim contacting surfaces. A generally disc-shaped shim is disposed on the upper side of the valve lifter partition section. The shim has an upper side in slidable contact with a cam, and a lower side in contact with the upper side of the valve lifter partition section. At least one lifter engagement groove is formed at the lower side of the shim.

Abstract: A curable epoxy resin composition comprises (I) an epoxy resin and (II) a curing agent. It may comprise (III) another curing agent. It is preferable for it to comprise 25 to 95 wt.% of (I) and 5 to 45 wt.% of (II).1 an epoxy resin (I) represented by the general formula: ##STR1## wherein Z represents a group selected from among a hydrogen atom, a methyl group and an ethyl group, R represents a group selected from among a hydrogen atom and alkyl groups, and n represents a number of 0 to 1.6, and2 a curing agent comprising a polyamine reaction composition (II) obtained by reacting 1 mol of a phenol (II-1) having at least one unsubstituted reactive site in the aromatic nucleus with at least 1 mol of an aliphatic polyamine (II-2) and at least 1 mol of a carbonyl compound (II-3) having at least one carbonyl group in the molecule.

Abstract: A central system fluid composition composed of 5-30% by weight of a viscosity index improver, up to 10% by weight of another additive, and the balance being a hydrocarbon-type base oil, which is characterized in that the hydrocarbon-type base oil is composed of 50-100% by weight, based on its total weight, of at least one chief base oil component selected from the group consisting ofA. polybutenes with an average molecular weight of 100 - 500,B. homo- or copolymers with an average molecular weight of 100 to 500 of at least one .alpha.-olefin containing 2-12 carbons, excepting butenes, andC. hydrogenation products boiling at 250.degree.-380.degree. C of high aromatic components which are obtained by cracking petroleum oils,And 0-50% by weight, based on its total weight, of a mineral oil; and that the viscosity index improver is composed of at least one component selected from the group consisting of1.