BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an upper portion of an engine having an oil level indicating system according to the present invention.
FIG. 2 is a portion of a cylinder head showing passages incorporated in the present oil level indicating system.
FIG. 3 is a perspective view of a cylinder block according to the present invention.
FIG. 4 is a sectional view of an engine having an oil level indicating system according to the present invention.
FIGS. 5 and 6 are view of a portion of a prior art oil level indicating system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, oil level indicator 10 is mounted within boss 30 which is integral with camshaft cover 26. Boss 30 has a bore 34, through which indicator blade 12 extends. Boss 30 is sealingly engaged with cylinder head 14. This sealing engagement is with cylinder passage 36, through which blade 12 passes. Cover 26 encloses camshaft space 64. This is shown in FIGS. 1 and 4. Because camshaft 18, which has a number of cam lobes 22, rotates at half crankshaft speed, a great deal of oil is thrown about camshaft space 64. However, because camshaft cover boss 30 is sealed to cylinder head 14 about cylinder head passage 36, fugitive oil is prevented from entering indicator passageway from camshaft space 64. As shown in FIG. 4, the indicator passageway extends upwardly from oil pan rail 52 of cylinder block 42 to cylinder head mating surface 56. This portion of the indicator passageway is defined by an integral vent stack 48 (FIG. 3), which is cast onto an outside surface of cylinder block 42. As further shown in FIG. 4, cylinder block passage 46 extends generally vertically through cylinder block 42 and provides a passage for not only oil indicator blade 12, but also a crankcase vent passage, which is completed by passage 40 extending through cylinder head 14. It should be noted that crankcase vent passage 40 as completed by cylinder block passage 46, does not function as an oil drainback for camshaft space 64. For this reason, it is possible to get an accurate reading from indicator blade 12, because fugitive oil is prevented from entering an indicator passageway.
Returning now to cylinder head 14, as seen from FIG. 4 that cylinder head passage 36 extends generally through the cylinder head from lower portion of boss 30 to cylinder block mating surface 60. At the opposite end of indicating blade 12, a channel 66, is formed in oil pan 68 for the purpose of allowing clearance for indicating blade 12.
It is important to note that integral stack 48, which functions as a tube, is case in place with the bulk of cylinder block 42, and thereby obviates problems with prior art designs having externally mounted add-on tubes which were subject to leaks, dislodgement, and damage.
While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.