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Oil pressure is good once car is running for a while. Do others with 356 engines experience this slow build in oil pressure, (one minute) ? Completely cleaned oil filter and blew out tubing to and from oil sending unit also to filter and return line to block. Changed oil and filter and the oil is amazingly staying almost clear, not dark brownish black like drained oil. Checked bottom pan through the drain hole with a long screwdriver and pan bottom seems clean and screwdriver did not have any sludge on it when removed. So system seems clean and pressure builds to 50 psi when rpm is around 1000-1500. When engine is hot and at idle (500 rpm) oil pressure is just below 40 psi. Could this mean the pump is weak and should be rebuilt? Would appreciate any information.
Thanks

Dear Bill:

I was dealing with a transport today that had the same problem. Just the gauge. You can have the gauge and sender checked out if a mechanical gauge show rapid pressure build up.

If the mechanical gauge show slow build up then check the pick up for air leaks, but given your oil pressure stays good once the motor is hot I think it is the gauge.

Bill, just a thought . . . .

Most wear happens at start-up (- motor cold, cylinder walls have 'drained', etc). So until you've solved the oil pressure problem it might be worthwhile using an oil additive (friction modifier like Wynns). These leave a coating of slip agent like Molybdenum Disulphide or such on surfaces even when the oil drains away overnight. A few dollars for some peace of mind(?) might be worthwhile.

What kind of oil are you using? If it is too thick it will not circulate properly until the motor warms up.

You should use the thinnest oil you can, not the thickest, especially in cold weather.

The pressures themselves seem more than adequate. Assuming you have an electrical resistance pressure sending unit, they respond slowly with a bit of lag, and perhaps yours is suspect? I'd just substitute a mechanical bourdon-type type gauge and re-asses the condition.

Oil pump wear on these engines is about as common as snow at the equator. But You might check the oil pump relief valve to be sure it's functioning properly.

And yes, stay away from the heavy oils. You can't go wrong by using the viscosity recommended in your owner's manual.