whats your oil pressure at???

IDIoit

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ever since my last mishap, ive been noticing that my oil pressure is doing some crazy things.

ive always had the idiot gauge, but it always went to full pressure ever since ive had the truck.

last oil change was about 200 miles ago.

delo 400 15W40

super duty filter.

today i put a gauge on it to see real pressures.

when cold and high idle on, i get 20 psi...

after high idle kicks off, she drops down to 10 psi at idle.

20 psi at 2000 rpms.

40 psi at 2500

with a max of 45 psi at higher RPMS.

thinking about rebuilding my oil cooler, it has not been done since ive owned this engine.

afraid i kicked my bearings a$$

what do you think???
 

cpdenton

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Mine has run at those exact pressures for 20,000 miles or so.

My pressure sender has been on top of the turbo and it is now on one of the main journal ports right behind the oil cooler on the block.

Let's have a race to see whose engine spins a bearing first?

I am not in a hurry to rebuild one either.
 

IDIoit

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my gauge is at the same location.
turbo oil supply.

i will bet mine lets loose first.
wager: promar reman lol

did you see pressure changes when you moved the sender/tube?
 

cpdenton

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Ha....ummmm

I will have to pass on that bet....

No wait, I can go drain the oil and run it. I will be blown up in about 5 minutes! You still in?

Ok just kidding. I need my truck in two weeks to go camping.

I guess I'm out.
 

IDIoit

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ok, but i will drain my oil, and add sand.
we have to start it at the same exact time..lol

i gotta take this thing tomorrow...
but i have a spare 7.3 i could do a engine swap tonight lol
 

cpdenton

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I have a spare engine too, but mine is spread out all over a work table...might take more than one night, for me anyway!

I think you will be ok. I have been anyway. I know a rebuild is on the horizon, but I doubt either of us will have any problems tomorrow from it.
 

PwrSmoke

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The service manual lists 10 psi idle and 40-70 psi at 2200 rpm with hot 10W40 oil (exact temp not specified, presumably ~200F as with most other engine mfrs.). The IDI lube system is a low pressure, high volume system. Your oil pressure is perfectly normal.
 

IDIoit

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thats a "brick" lifted off my shoulders! thank you!

if i had 10 psi in my gassers, id be buying a new rotating assembly...lol
bore and stroke!
 

icanfixall

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Most idi engines run what you guys are seeing. As already posted. We run some high volume and at a lower pressure than many other engines out there. We push 18.2 gallons per minute at 3000 rpm. Many have found after a complete rebuild the oil pressure stays the same. I believe this is a well worn oil regulator spring in the rear cooler header. I have several taken apart that shows the wire the spring is made from has rubbed so much that its reduced in diameter. So the regulator opens at a lower pressure. When I rebuilt my engine I did what Russ did and shimmed up a new spring by 60 or 70 thousands using stainless steel washers. Buying a new rear oil cooler header was expensive too.
 

IDIoit

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as the oil cooler isnt an issue yet, as far as leaking, ill leave her alone for now.
but i will experiment on my next build when i tear her down.
hopefully Russ has a thread on it, ill do some searching.
 

chris142

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thats a "brick" lifted off my shoulders! thank you!

if i had 10 psi in my gassers, id be buying a new rotating assembly...lol
bore and stroke!
People often panic when they see low oil pressure.many big blocks in the 60's and 70's had such low pressure that the oil light would flicker @idle. 10 psi per 1000 rpm is perfectly acceptable.
 

OLDBULL8

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These engines are designed with a hi volumn and low pressure flow system, reason is to take away the hi combustion heat, think cylinder wall squiters and the hi flow oil cooler. 180*F to 190*F head coolant temp and crankcase oil temp at 230*F, oil cooler, oil out temp to filter, will be close to or equal to head temp. Coolant at the bottom of the radiator is ~20* to 25* lower than the top temp, that is with a good flowing radiator. With a turbo, the oil cooler has a few more tubes than an NA IDI to compensate for the higher combustion temps.
 

The Warden

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For what it's worth, I've had a mechanical oil pressure gauge on my engine the entire time I've had the truck (14 years and 75K miles)...and, hot idle's always been at 10 PSI. Hot oil at cruise RPM is generally between 35 and 40 PSI.

As others have said, they're low pressure, high volume engines...my pressure at cruise is a bit lower than "normal", but it's been steady there for 50K+ miles (ever since I swapped the ZF5 in), so I'm not too worried about it. And, certainly, idle is perfectly normal ;Sweet
 

fx4wannabe

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Personally I wouldn't get nervous unless your idle pressure is under 10 or doesn't get above 25 cruising.
 

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