Oil Question

Oil question? I just purchased a 77 B with very low miles (13K). I asked the last owner what grade of oil he put in the car and he said 10W30. The oil presser was 50 at idle and 60-65 at 30000 rpm. I got it home and changed the oil to Valvoline VR1 20W-50 ask was recommended to me. The presser is now running at 60-65 at idle and around 90 at 30000 rpm. Should I switch back to 10W30? I also put a Puralator oil filter on it. Thanks.

I understand my cars does the same thing yet every book says that 20/50 is the correct oil. My engine is a recent rebuild with a new oil pump which I thought may be part of the situation. However, as it warms up there is some drop in pressure so I say go with the recommended oil.

Oil question? I just purchased a 77 B with very low miles (13K). I asked the last owner what grade of oil he put in the car and he said 10W30. The oil presser was 50 at idle and 60-65 at 30000 rpm. I got it home and changed the oil to Valvoline VR1 20W-50 ask was recommended to me. The presser is now running at 60-65 at idle and around 90 at 30000 rpm. Should I switch back to 10W30? I also put a Puralator oil filter on it. Thanks.
20/50 is the factory recommended oil to use. Your excessive oil pressure might be caused by the oil release valve on the left rear bottom side of the engine. It might be sludged up if it wasn't pulled and cleaned during rebuild. It gets missed a lot. Look in a Moss catalog under MGB engine parts and it will show an exploded view of it. Be careful removing it as it has a fairly stiff spring inside. Could be your problem. PJ
For a motor oil education, go here: http://www.nordicgroup.us/oil.htm