Originally Posted by atcoscrazyest69
ok well i have another delema i just got done putting my motor back together and i have a loss of oil pressure when hot. motor is a 400 .30 over mild cam crank is freshly cut .10 .10 and was balanced to my pistons the pump is a new melling high volume the shaft is new cam bearings are new oil plugs are new
when i start up in the morning it goes to 60 idle driving down the road at 2k around 85. but once it warms up to about 190 hot idle it sits between 16-21
its a manual guage i have switched it with another same problem. my oil pickup is welded and sits a 3/4 of an inch from the bottom of the pan im lost i dont understand. any ideas ? my first 20 min startup i left it at 2k for 15 mins to break in the cam and ran 10-40w it did it then i noticed it on my test drive. came home saw the problem drained the oil it was a little silvery but i figured that was the rings to cylinder wall all the normal breaking in so i put my 20-50 in and a new ac delco filter and bang still does it i dont understand please help
This would be normal. Before getting into that let me say that the pick up being 3/4 inch off the bottom is too high it should be more like 1/4 to 3/8ths. If it's too high you run the risk of exposing it to air pick up if the oil level falls a little low.
Oils have great viscosity differences when cold but they gather in a pretty tight group when hot, I rather doubt that the differences in what you've used would be measurable on anything but lab quality sensors and instruments let alone on the rather crude gauges we run in the car. If the pressure comes up from the 16-21 at idle to about 55-60 at a 2000 then things are running pretty normally. Just fix the pick up depth. Your mechanical gauge also has a buffer in it so its resonse rate will be behind the actual changes, this is there to keep it from blowing apart. An electric gauge is usually more prompt in registering changes but introduces the probibility of electrical failures giving false data. I usually run both types and compare them, but I like old round gauges, they bring out the pilot in me making me feel safe and informed even if I'm not really.