Patent ID: 7100744

Claim:
An engine comprising: a body that includes a cylinder block and a crankcase, a hole formed in the engine body and communicating at its lower end with the crankcase, a cap for closing the mouth of the hole, and a dipstick depending from the underside of the cap which reaches through the hole into the crankcase in order to enable the oil level within the crankcase to be determined, and characterized in that: the engine body is formed of a cylinder block and a separate cast oil sump secured to the cylinder block, the hole for the dipstick being formed in the oil sump casting with an overhanging lip adjacent the mouth of the hole formed by a part of the cylinder block that projects laterally beyond the oil sump, and the cap comprises a spigot rotatably received in the mouth of the hole and a flange extending radially outwards from the spigot to cover the mouth of the hole, the flange being non-circular so that by rotation of the cap relative to the hole, a radially projecting portion of the edge of the flange may be selectively engaged beneath the overhanging lip to prevent axial displacement of the cap and the dipstick relative to the engine body.