Low Oil Pressure
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Joined: Jan 2010
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Low Oil Pressure
I have a new (to me) '86 F-350 with a later IDI 7.3 engine with an early Banks non-wastegate turbo set up.
The engine has been rebuilt and came out of a Cornbinder school bus. In order to shoe horn it into the F-350 I changed the front sump Cornbinder pan and pickup, exhaust manifolds, and oil cooler with the stuff off of dead 6.9 that came out. The inside of the motor looked clean enough to eat off and the rod bearings passed the "babbit beater" clearance test when changing the pan. I did however forget to punch the ball bearing out of the rear dipstick boss in order to use the Ford rear sump dip stick.
The oil pressure, according to the factory gauge and a suspect/damaged aftermarket gauge, never gets past ½ scale / 25 lbs and drops off to near zero hot. I have changed from fresh Delo 400 30wt to fresh Rotella T 15-40wt with new filters. (10 qts)
The aftermarket gauge is buried in the dash and the connections under the hood are buried under the turbo stuff. I will change it out as soon as I get a chance to take the dash apart.
My questions are these:
Does the ball bearing driven into the rear dipstick boss come out the top or bottom? Can I drive it into the pan and fish it out the drain whole with a magnet, so that I can install a usable dipstick?
Does anything besides worn rods and mains or a stuck oil pump bypass cause this kind of behavior in a 7.3?
Can you get the pan off of the motor w/o taking it out? This thing was such a PITA to get in with the turbo bracket in place I would jump through a bunch of hoops to avoid removing it again.
The oil was clean and did not show any signs of fuel contamination as might be found with a leaking lift pump diaphram, and I used a different brand oil filter.
What it typical oil pressure hot in one of these and what is the minimum safe oil pressure under moderate load?
The engine has been rebuilt and came out of a Cornbinder school bus. In order to shoe horn it into the F-350 I changed the front sump Cornbinder pan and pickup, exhaust manifolds, and oil cooler with the stuff off of dead 6.9 that came out. The inside of the motor looked clean enough to eat off and the rod bearings passed the "babbit beater" clearance test when changing the pan. I did however forget to punch the ball bearing out of the rear dipstick boss in order to use the Ford rear sump dip stick.
The oil pressure, according to the factory gauge and a suspect/damaged aftermarket gauge, never gets past ½ scale / 25 lbs and drops off to near zero hot. I have changed from fresh Delo 400 30wt to fresh Rotella T 15-40wt with new filters. (10 qts)
The aftermarket gauge is buried in the dash and the connections under the hood are buried under the turbo stuff. I will change it out as soon as I get a chance to take the dash apart.
My questions are these:
Does the ball bearing driven into the rear dipstick boss come out the top or bottom? Can I drive it into the pan and fish it out the drain whole with a magnet, so that I can install a usable dipstick?
Does anything besides worn rods and mains or a stuck oil pump bypass cause this kind of behavior in a 7.3?
Can you get the pan off of the motor w/o taking it out? This thing was such a PITA to get in with the turbo bracket in place I would jump through a bunch of hoops to avoid removing it again.
The oil was clean and did not show any signs of fuel contamination as might be found with a leaking lift pump diaphram, and I used a different brand oil filter.
What it typical oil pressure hot in one of these and what is the minimum safe oil pressure under moderate load?
Cargo Master
Joined: Feb 2008
Posts: 3,409
Likes: 1
From: back in SE Iowa
Duecento welcome to FTE and the idi forum
hang in there lol ,i personally cant give an an answer but someone will be along that can.sounds like you have an interesting truck i would like to see some pictures of the motor swap if you have any
hang in there lol ,i personally cant give an an answer but someone will be along that can.sounds like you have an interesting truck i would like to see some pictures of the motor swap if you have any
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
The pickup screen in the oil pan is too close to allow the ball out...... so don't do that. You can remove the pan, or at least drop it down in truck so as to recover the ball. I will PM you a lead to that info.........woops can't do that.... can you allow PMs in yet.
FYI you will have to lift the engine slightly in the procedure.......
The oil pressure on a hot engine is 10 psi at idle and 40-70 at 3000rpm
FYI you will have to lift the engine slightly in the procedure.......
The oil pressure on a hot engine is 10 psi at idle and 40-70 at 3000rpm
