I have a newly rebuilt 350 smallblock with a high volume oil pump. I was just wondering how much should the oil presure be when it is in gear, I know as it gets warmer it will drop some cause of it getting hot,and plus it aint broke in all that good yet. In my old moter it stayed around 20 when it was hot . my motor now runs around 40 now, but today the temp gauge was running around 170 and the oil presure droped to around 35-40. how low is to low??? im not worried about it, but would like to ask ya'll advice. My gear is 411 so im running around 3000-335000 rpm going down the road. thanks
Do you have a good expensive oil pressure gage? You will need one to accurately keep track of the engine oil pressure. What viscosity oil are your running? I run 10w 50w racing oil. You get what you pay for. I also only run a stock oil pump, never gave me any problems on any of my rebuilt or race engines. The 35-40 psi oil pressure should be fine. You are right, as the engine oil gets hotter the pressure will drop some, that is nothing to worry about. If you are concerned get an oil pressure cutoff and install it to kill th ignition if the oil pressure drops to a dangerous level.
Do you have a good expensive oil pressure gage? You will need one to accurately keep track of the engine oil pressure. What viscosity oil are your running? I run 10w 50w racing oil. You get what you pay for. I also only run a stock oil pump, never gave me any problems on any of my rebuilt or race engines. The 35-40 psi oil pressure should be fine. You are right, as the engine oil gets hotter the pressure will drop some, that is nothing to worry about. If you are concerned get an oil pressure cutoff and install it to kill th ignition if the oil pressure drops to a dangerous level.
How many of you know what the oil pressure in an ls1 is ?
6psi at 1000 rpm 18 psi at 2000 and 24 at 4000 hot.Your engine requires a certain rate of flow that the engineers at the big 3 have figured out.Most Winston cup cars at 800 HP only have 45 to 50 psi of oil pressure.If you control the internal oil leaks in an engine you do not need that high volume or pressure pump.A small block Chevy with .0025 in the mains an .002 at the rods will need nothing more than a stock pump blue printed.
A high volume pump should not increase the pressure, How ever it will put more oil on the top part of the engine, thus leaving less in the oil pan for the pump to work with. When a customer wants a high volume pump, I use pipe cleaners in the push rods to cut the flow to the rocker arms. I have seen them fill the valve covers so that the valve stems was standing in oil. causing excessive oil consumption.
Troy
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With the engine hot the stock specs for a 350 are 15-20psi at idle-in gear. With the addition of about 100 rpms the pressure should be 30psi. At 2000 rpms the pressure will be 45-60. This is with a regular oil pump. With a high pressure you will be 10 to 15 higher on all specs, a little also depends on your choice of oil, but not that much. Good luck.
I was told by a wise old engine builder that your oil pressure is how much pressure it takes to move the oil, not how much oil is moving. The hotter the thinner, the colder the thicker. Higher RPMs add to presser of course. I was always worried till I he told me that, but it makes sence.
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