I have a 1973 mercury 460 in my 1980 F-150. When I first bought it oil pressure was a steady 40 psi when warmed up at idle. it was 70 psi when first started... Its been about 6 months since I bought the truck. It is still 70 psi when cold. after driving for awhile my oil pressure dropped to about 25-30 psi at idle. It still picks back up to around 50-60 psi when driving and warmed up. I made a long trip yesterday with the engine running for about 80 miles one way.. It held a steady 50 psi when doing about 60-65 mph when dropped back down to idle it was about 20 psi. Should I really be worrying about 20 psi at warmed up idle? the oil pressure picks back up as soon as a I start to give it some gas. Is 20 psi ok for a 460???

Travis

 

No need to be concerned. The 460s all seem to run rather low pressure at idle once they're warm. There was a thread about this a couple months back with a member running only about 10psi at warm idle and it drove fine like that for years. Mine runs about 15psi at warm idle and will increase to 30-35 while driving.

 

25 psi is real good (with 10-30/10-40 oil) 7psi is minimum safe presure, 20 is pretty good, don't worry about it.