It's a mechanical gauge, and working properly unfortunately.
MGBs do have a fairly lazy oil pump. 25-40 at idle is about norm when hot, and 44-55 at speed. My GT was lower, but it did have 250k since the rebuild.
This one was 50 at startup, dropped to 2lbs at idle. 25lbs when hot at 4,000, and around 5 pounds at 2,000 rpm. The speed at which it dropped alarms me, because it's not a healthy engine. I attribute it to worn cam bearings and worn oil pump, and new rod bearings on a worn crank. It had noticeable ridges on the rod journals but I crossed my fingers and ran it anyways.
I figure it will bed-in and run just fine with low pressure so long as the flow stays adequate, or if something is deteriorating it will eat itself alive quickly, lol! Either way it's a junk engine so we are gonna run the thing till it blows! Any bets on how long that will take?
If we had more time I'd have rebuilt our super-cheaty race motor. You know, the one that made at LEAST 67rwhp, unlike them lowly Sunbeams.
"Real ZomBees prefer Bacon"
IOE(x2) MGB/SAAB 96, Judge's Choice, Class C Win, & 2011 Hooniverse Car of the Year!
MRolla, Stick Figure/Animal House, Free Range MR2, SAAB Sonett, "The Death Flip"
2008 Exoskeleton Jag Fiasco, Concours d Lemons - Rue Britannia, worse British car.