I imagine the worse scenario Hello Pat
If the pressure is ok at start up and decreases as the oil temp goes up, you still need more information. At an oil temp of say 200 deg, what is the pressure at idle and at 2500 RPM. The minimum pressure at idle is low, I can't say for sure without my book, but, 10 PSI sticks in my head. Others will surely add to what I say. At cruise speed, hot, the engine should make around 30 PSI. Again these are guesses. There are such things as pressure relief valves with springs that need to be checked, as well as the pump. Before engine assembly, the crank and bearings should have been bolted together with the case halves along with a material call plasti-gauge. A small smear of this material is placed on the bearing shell and is squeezed in the bolting process and then can be measured with a gauge supplied with the material and you can determine if the bearings are too loose. Since you are together and running, I would suggest trying this. CAUTION WORKING AROUND A OPERATING ENGINE ESPECIALLY ONE WITH A PROPELLER IS DANGEROUS. KEEP YOUR HANDS HEAD ARMS AND ALL OTHER BODY PARTS CLEAR OF THE PROP AND OTHER MOVING ENGINE PARTS. Listen to the engine while running with a piece of plastic tubing, used as a doctor might listen for a heart beat. listen to the case at the parting line for clicking or ticking noises. If you listen near the valves you should be able to hear each of them. If you don't hear any odd noises, make your initial search for another cause for poor pressure. The use of a high volume pump is an option if the one you have is standard. Orma Southfield, MI N110LR celebrating 20 years Flying, flying and more flying http://www.kr-2.aviation-mechanics.com/
