hfunccius Posted February 21, 2019 Share Posted February 21, 2019 I have an original 6 cylinder rebuilt motor. Problem with oil pressure (I think), starts @ 70 psi, driving drops to 20 psi and at idle drops to 5+ psi. Tried changing springs in the oil pressure regulator. Test gauge and oil gauge read the same. Any suggestions? Link to comment Share on other sites More sharing options...
Spinneyhill Posted February 21, 2019 Share Posted February 21, 2019 What oil are you using? That is way too high at cold start. It sounds like you are using a high viscosity oil. Put the original spring back in the oil regulator and .... Have you tried a 5W-30? I changed from 20W-50 to 5W-40 in my 1930 Dodge 8 and it made a big difference. The oil pressure at startup is not hugely higher than the running pressure. Idle doesn't matter too much, as long as there is some. But of course, it means that pulling away at low speed in a high gear is very hard on the bearings because the oil film is not as good as at higher revs. Link to comment Share on other sites More sharing options...
Mikefit Posted February 22, 2019 Share Posted February 22, 2019 Oil pressure is controlled by the spring loaded pressure valve this valve will open when the pressure reaches a pre set pressure. Normally what ever the dash gauge shows as the highest reading. Should the gauge read. 0 - 30 - 60 valve will open at 60# +or - now engine warm road speed over 30 MPH oil pressure 30# + or - . At idle 500 to 600 RPM oil pressure would be in the range of 5 to 6 psi. The rule of thumb is you need 10 PSI for every 1000 RPM Mike Link to comment Share on other sites More sharing options...
Mattml430 Posted February 22, 2019 Share Posted February 22, 2019 I followed Spinneyhills advice with the oil weight in my 6 and also adjusted the oil pressure regulator with great results. I found I had to adjust the valve in very small increments, drive it a little, adjust it a bit more until it was rite. Adjust it a tiny bit at a time. Link to comment Share on other sites More sharing options...
hfunccius Posted February 23, 2019 Author Share Posted February 23, 2019 On 2/21/2019 at 4:11 PM, Spinneyhill said: What oil are you using? That is way too high at cold start. It sounds like you are using a high viscosity oil. Put the original spring back in the oil regulator and .... Have you tried a 5W-30? I changed from 20W-50 to 5W-40 in my 1930 Dodge 8 and it made a big difference. The oil pressure at startup is not hugely higher than the running pressure. Idle doesn't matter too much, as long as there is some. But of course, it means that pulling away at low speed in a high gear is very hard on the bearings because the oil film is not as good as at higher revs. Thanks very much for your reply. I am using 5W40 and I think I'll let it go at that Link to comment Share on other sites More sharing options...
hfunccius Posted February 23, 2019 Author Share Posted February 23, 2019 On 2/21/2019 at 9:29 PM, Mikefit said: Oil pressure is controlled by the spring loaded pressure valve this valve will open when the pressure reaches a pre set pressure. Normally what ever the dash gauge shows as the highest reading. Should the gauge read. 0 - 30 - 60 valve will open at 60# +or - now engine warm road speed over 30 MPH oil pressure 30# + or - . At idle 500 to 600 RPM oil pressure would be in the range of 5 to 6 psi. The rule of thumb is you need 10 PSI for every 1000 RPM Mike Thanks for your info. The rule of thumb is just what I needed. Link to comment Share on other sites More sharing options...
hfunccius Posted February 23, 2019 Author Share Posted February 23, 2019 23 hours ago, Mattml430 said: I followed Spinneyhills advice with the oil weight in my 6 and also adjusted the oil pressure regulator with great results. I found I had to adjust the valve in very small increments, drive it a little, adjust it a bit more until it was rite. Adjust it a tiny bit at a time. Thanks a lot, I'm trying different oil pressure springs in my oil pressure regulator. Link to comment Share on other sites More sharing options...
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