Oil return

Just after some advice please. New engine build, and no oil coming back to the tank, after running for 5 minutes. Plenty of oil in crankcase, 1 1/2 cups. Oil lines are as per manual I.E feed. Is outer line. Cracked of rocker feed, and pressure there when rotating engine. Removed return line at pipe from case & no oil. Blew compressed air down pipe and it pressurises, I would have thought air would pass through pump to crankcase? No oil in filter either. I had altready primed up crank with oil can at rocker feed junction. So I have pressure but apparently no scavenge?
Any ideas?
Cheers Richard

Stockie 2 , standard practice to observe oil return to oil tank with cap off on initial startup after a few seconds or a minute. Use flashlight,will burble and blurp,no steady stream. Perhaps you forgot to fill oiltank, has been done before.Oil pump gasket reversed ?Oil lines reversed? 5 minutes will survive on assembly oil but start scatchin' your head ,leave out any seals timing side ?

Thanks goodness fed side fed. To go further need to know what engine version. Combats have a cast passage in DS case that can be plugged unseen. I'd pull inner return hose on engine manifold which should spray oil/air out in seconds if not immediately, if not remove oil pump and blow passages to listen for blocks or clear swarft. Drain sump to get ID of how much was going in to also be comming out.
Dang that sucks if not just crank still filling. My took like 45 sec to show hints at tank though a filter then a min to really see effective return. I did not idle my start up but rev'd straight to cam saving 2000-4000 so maybe you just ain't had enough rotations yet at some speed. It barely dribbles at idle.

Thanx Trontian & Hobot, I have got pressure just no return, Hobot engine is an 850. I was sure it should have returned oil by now. I will pull the timing case and dig deeper, I am thinking the oil pump gaskit, reversed?
Cheers Richard & thanks

stockie2 said:

I am thinking the oil pump gaskit, reversed?

Click to expand...

Way too easy to do. Look closely..

That gasket is a trap, the outline on mine dose not line up with either the case or the pump housing. But yes I did not have the holes lined up. Looked okay when fitted the to case, but not so good when fitted against the pump. So we are back on track now, thanks everyone.

Cheers Richard

Thats what we call , Blue Printing , Going over with a fine tooth comb , inspecting under a magnifying Glass ,
( As Per Sherlock Holmes ) and takeing nothing for granted , and leaving nothing to chance .

Not to worry , Brother worked as Dewcati & Meridan ( communist ) Triumph Mechanic , New jubillie had pump gasket
on one studd only . He spotted the corner of the gasket hanging out of the timing cover joint . & had passed ' Factoy
inspection ' , as was brand new , inspect & commision .