oil pressure question

Slide · #1 (**permalink**) 08-11-2002, 10:11 AM

I have a 351W. with a Milodon high press&vol. oil pump,windage tray and baffeled trap door road race pan. I have run both 20/50 and 10/40 oil. I have a S.W. mech oil press. gauge so the real pressure readings may be suspect but the relative drops should be reasonable. On initial start-up I see 60psi, as it warms up the pressure drops to 40, at idle it can go to 30. Is a 20deg drop reasonable from cold to hot as it will not go much over 40 even at 5k? Thanks for any input.

RACER X #99 · #2 (**permalink**) 08-11-2002, 10:24 AM

Slide,
I was also concerned about only 40 lbs. pressure on my 351 W but was told by many others running the sb Ford that because of the much better oiling system than the other engines from Ford ie. FE, Cleveland and others , the sb has no problem delivering oil to all parts of the engine at a much lower pressure. That 10 lbs. per 1000rpm may apply to the older engines but I also believe the sb will live just fine at 40 psi.
I also learned by watching some Nascar technical shows that the Nascar Windsors run as low as 20 psi for qualifing attempts and 30-35 psi in race trim. If those engines can live at 7000 plus rpms with only 35 psi I am sure our engines can live at 40 psi.

Cranky

DAVID GAGNARD · #3 (**permalink**) 08-11-2002, 11:10 AM

Clyde;

I am running a 350 hp 351-W in my 65 Fastback with a stock oil pump and windage tray... I run 15/40 Shell Rotela oil,these are my readings; cold start-up- 55 to 60 psi at 750 rpm idle,fully warmed, 30 psi at 750 rpm idle,anything above 1500 rpm warm-up it runs 50 to 55 psi..... A number of engine builders told these numbers were just right..... I think as long as you have 25 to 30 psi at idle you'll be o-k....I have seen some dirt track cars with a lot of clearance in their engines idle at 20 psi and race at 50 to 60 psi on the oil pressure and run all season like that...

David

SCOBRAC · #4 (**permalink**) 08-11-2002, 01:52 PM

yes..

Slide · #5 (**permalink**) 08-11-2002, 02:49 PM

Thanks guys, I guess this is another thing I do'nt need to worry about

Kputz · #6 (**permalink**) 08-14-2002, 09:53 PM

Keep in mind that oil pressure doesn't measure oil flow, but rather resistance to same. Particularly with the thinner oils like Mobil 1 20 libs at idle should be pleanty, and much over that 60 at start up could spell trouble.