A method for an engine, the method comprising: upon aligning of second vertical and supply channels (504, 910) only during opening of a valve coupled to a tip of a rocker arm (905, 907), selectively splashing lubricating oil to a cover of the rocker arm (905, 907) and supplying the splashed lubricating oil to the tip of the rocker arm (905, 907), wherein the cover includes a surface having one or more protrusions (926, 928, 966, 968) thereon, wherein the one or more protrusions (926, 928, 966, 968) includes a first set of protrusions (926, 966) on the cover at a first side of the cover and a second set of protrusions (928, 968) on the cover at a second side of the cover, wherein supplying the splashed lubricating oil to the tip of the rocker arm (905, 907) includes guiding the splashed lubricating oil from a ridge to the first side of the cover following a first downward slope sloping downward away from the ridge and then dripping the splashed lubricating oil on the tip via the first set of protrusions (926, 966), and wherein the method further comprises supplying the splashed lubricating oil to another tip of the rocker arm (905, 907) by guiding the splashed lubricating oil from the ridge to the second side of the cover following a second downward slope sloping downward away from the ridge and then dripping the splashed lubricating oil on the another tip via the second set of protrusions (928, 968), the another tip coupled to a drive cam via a pushrod (924, 927), wherein a first amount of oil dripped from the first set of protrusions (926, 966) on the tip is higher relative to a second amount of oil dripped from the second set of protrusions (928, 968) on the another tip. upon aligning of second vertical and supply channels (504, 910) only during opening of a valve coupled to a tip of a rocker arm (905, 907), selectively splashing lubricating oil to a cover of the rocker arm (905, 907) and supplying the splashed lubricating oil to the tip of the rocker arm (905, 907), wherein the cover includes a surface having one or more protrusions (926, 928, 966, 968) thereon, wherein the one or more protrusions (926, 928, 966, 968) includes a first set of protrusions (926, 966) on the cover at a first side of the cover and a second set of protrusions (928, 968) on the cover at a second side of the cover, wherein supplying the splashed lubricating oil to the tip of the rocker arm (905, 907) includes guiding the splashed lubricating oil from a ridge to the first side of the cover following a first downward slope sloping downward away from the ridge and then dripping the splashed lubricating oil on the tip via the first set of protrusions (926, 966), and wherein the method further comprises supplying the splashed lubricating oil to another tip of the rocker arm (905, 907) by guiding the splashed lubricating oil from the ridge to the second side of the cover following a second downward slope sloping downward away from the ridge and then dripping the splashed lubricating oil on the another tip via the second set of protrusions (928, 968), the another tip coupled to a drive cam via a pushrod (924, 927), wherein a first amount of oil dripped from the first set of protrusions (926, 966) on the tip is higher relative to a second amount of oil dripped from the second set of protrusions (928, 968) on the another tip.