Low Oil Pressure 356

Posted by Lauren R Lampi On 2014/6/14 13:17:53

I have a 47 Custom Super Clipper, 356 OD That is having low oil pressure readings. Car has 59,000 miles on the odometer. Did some engine work 5 or 6 years ago
Just got everything together and ready for the road.
Start the engine and it takes about 30 seconds for the oil pressure gauge to go up to about the 40 mark. Driving the car at in town speeds the gauge reads at the 40 mark. As the temperature warms up, the oil pressure reading drops.
I took the 47 on a 10 mile loop yesterday. Pressure started out at 40 when the engine was cold. As were progressed on the loop, country roads at 40 mph, pressure still about 40.
Operating temp right on the center of the gauge. on the highway part of the loop, 55 mph and everything getting warmed up, the pressure dropped a bit. When I got back to my garage the oil pressure was just off the low peg, maybe about 5 to 10 lbs. I only have about 50 miles on the engine work.
When I bought the car about 8 years ago. I don't remember anything about the drop off in oil pressure. Been working on the car for about the last 7 or 8 years.
Engine work done:
New rings, standard size; All new valves, valve springs, New
lifter inserts, New standard size rod bearings, new water pump, Rebuilt starter and generator, new electrical parts,
new wiring.
After the mechanical work was done, the car went to the body shop for the body work and paint.
Brakes, tires and interior also completed.
Now I want to drive the 47, but the oil pressure is the problem. Where do I look next. New oil pump? New oil pump pressure bypass spring. Different oil? I am trying
a straight 40 weight now. I was using a 30 weight to start
out with last year.
The temperature stays right in the middle of the gauge.
Any new ideas??

Lauren R Lampi
Grand Rapids, Minnesota