today i cahnged the oil filter and oil in my recently rebuilt 4agze 3500ks old. only about 2ltrs of oil came out, including what was in the filter, even after sitting there for ages, draining. It took a bit over 3.5ltrs 2 fill with oil. Is this oil usage normal? it doesnt blow any smoke or anything liek that and it doesnt leak oil so where the fuk has all my oil gone?