Regulating oil pressure.

Posted by DrMorbius On 2016/10/14 16:35:41

Hi, this concerns the oil pressure on a 1939 Super-8 motor. I have the correct amount of 10w-40 Rotella oil in the crankcase. Now, reading the dash pressure indicator when I start the engine from cold I get about 20-25 lbs at idle. On a 15 mile trip with the engine warmed up it reads 40-45 (at 50 mph) but at the 14 mile point I noticed it indicated around 30-35 lbs (still 50 mph). First thought was oil pump wear (engine has 200 miles since rebuild but not known if oil pump was reconditioned or just stuck back on). An incredibly knowledgeable person from the forums (not sure I should mention his name, I should ask!) suggested the problem could be the oil pressure regulator and that it should be removed, cleaned and adjust the spring inside. My mechanic that I've used for 20+ years suggested if I don't want such a disparity in pressure just go with straight 30w oil.....he's a bit old fashioned when it comes to newfangled multi-viscosity oils. He also said 30 lbs at 50 mph will not hurt the engine, yet the Packard manual suggests 55 lbs ay top speed. I myself prefer multi-viscosity oils, but that's just me.
Which way should I go?

Thanks,

Steve