oil flow problem on sr20 engine

[spannerman]

working on sr20 engine. inlet cam worn out . cranked engine with rocker off. no oil flow. flushed dirty oil out. used diesel/ pariffin to flush. run for 4/5 mins. Got flow back. only of about 2 mins. run for 5 more mins. flow interminent. finally no flow coming from oil tubes.. unblock oil tube(over cams) with airline/pareffin. & refitted. no flow...suspect oil pump...renew oil filter..interminent flow only over 3000rpm.no flow less than that..oil pump off... pump rotor minimal play & smooth rotation.tested with thin diesel flow ok..tested with thick old oil flow ok..dismantled oil pump, cover casing has only one deep score. smoothed with 80 paper,120,400 to polish. score is now a light scratch.clean lube.reasemble. rotor has no play turning is smooth & feels very slight stiffness. tests: fitted with strainer unprimed using old oil 10-15 turns oil pours out. slighly quicker.....Anyone tell me of any other cause of oil flow restriction.....or any one can send me engine diagrams, pressure spec..thanx