dwknight

I just completed a 5.0 HO with EFI engine swap in my 59 Ford Ranchero. The first engine had low oil pressure and some other problems. I pulled that one out and installed a known good engine and it too has low oil pressure after the engine gets hot. I had to change the oil pan to a front sump for the swap. I also changed the pick up tube for the front sump. After the engine gets hot the oil pressure light comes on at idle and the gauge reads about 5lbs. It will go to 15-20lbs when reved up. This engine had great presure in the donor car. I installed a new oil pump with the pan change. Any ideas?

Timspony

Mechanical oil pressure gauge?

dwknight

I have the original idiot light and have added a mechanical oil pressure gauge. Light comes on at idle and gauge reads real low, about 5lbs at idle. This is only after engine gets hot. Great pressure when cold and during warm up.

86HOGT

I had a 302 that did that same thing when I put it in my old Bronco. Sounds likes it just worn out...too much bearing clearance...

Funny thing is too...before the swap it ran in a 79 Mustang okay.

mjr46

do you have the pick up to pan adjusted at the proper clearance/height.......usually you want no more than 3/8 of an inch between pick up and bottom of pan...also how many miles did the motor have on it before swap??

mustangsneverdie

mine does the same thing its around 20 psi at idle and around 50 psi (at 2000 rpm) when its cold but when it gets to oper. temp. it idles around 5-10 psi and then about 30 psi (at 2000 rpm)

93 LX FiveO

5-10 psi at idle is not healthy for a 302.

yes it will run, but wont last.

my 5.0 is starting to lose pressure as well

saleenpride1986

Sorta off this specific pressure topic, my oil pressure meter in my stock 1990 gauge cluster shows at about middle all the time, then once im driving for about 5-7 minutes it drops down to 1/4. There is no leak, no pressure change as we've tested the lines and all cylinders. Could it be a faulty gauge, wire, sensor, anything of that sort?

Cause from what I recall it is just the pressure, even though i have a diff engine would it matter to that gauge even if it has more oil in it, or is it specifically for the exact dimensions of the 5.0 in it originally?

ctgreddy

sounds like a rebuild is needed. if its not too extensive to change oil pumps try putting the old one back in there, if it had good oil pressure before with it maybe it'll get it again. might make the motor last longer.

mustangsneverdie

I've had 3 5.0 motors in my car since I've had it the first one was a stock H.O. it had great pressure at idling (about 20) and around 50 at 60mph the second one was a stock 302 flat tappet cam and it would idle the same as the motor I have in my car now(about 5-10)