Folks - '56 272 just rebuilt mostly with new components inside. I left the cam in place. Checked out OK. I get 50 pounds of pressure at cold idle and that goes to about 45 when I rev it up. Pressure drops to a scary 10 at temperature and increases to almost 40 at cruising RPMs. I can't identify a source here for verification that this is OK. Looking for a few thoughts...

(Running 15/40 Shell Rotella)


Thanks in advance.
Calvin

 

As indicated on the dash gauge, or - ? -

 

EDIT: 20 pounds at warm idle and +/- 50 at cruising RPMs. I have a test gauge hooked up but it wasn't tightened in all of the way so it had a slight leak. I think I'm OK with these numbers, correct?

 

Sounds like plenty to me.

 

My 272 with fresh complete rebuild, lower end, cam, etc, shows a bit more with 10W30 and running a mechanical gauge. What you are seeing would be consider acceptable if you are getting a full supply of oil to the rockers. It was not uncommon to see the low oil pressure light flicker at hot low idle when these vehicles were new. Note: Not all vehicles had the gauge, some just idiot lights.
Be aware, when you make a quick stop or go down a very steep hill, the oil pressure will drop to zero on the truck due to the oil pan configuration.. Rear sump, nearly flat pan and no baffles, the oil runs away from the oil pickup screen.

 

Definitely getting oil to the rockers. But I do think I need the valve lash adjusted again. It was done when the engine was torn down and should be done again just for verification purposes with engine back in. Great info here fellas. I appreciate your feedback.

 

You absolutely need to re-do the valves after a teardown.