Andertusa
Full Access Member
I don't have my truck running yet, but what kind of oil pressure can I expect it to safely run, say maybe minimums and maximums?
Operating Oil pressure?
- Thread starter Andertusa
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If I am not mistaken, The minimum range is 10 psi at idle (650 rpm), 40 psi at 2000 rpm (no load). I looked into it a while back and, if I remember correctly, that is the minimum psi.
My electric gauge reads between 38-40 psi at 2000 rpm. I hooked a mechanical to it and it read 50 psi at the same rpm. So I figure I am safe. I use the electric for daily use to avoid the possibility of oil in the cab.
My electric gauge reads between 38-40 psi at 2000 rpm. I hooked a mechanical to it and it read 50 psi at the same rpm. So I figure I am safe. I use the electric for daily use to avoid the possibility of oil in the cab.
Just my $.02...
To the OP, it looks like you already have a good answer, but for what it's worth, I see 10 psi at hot idle, and between 35 and 40 psi at freeway speeds. My pressure went down a bit after I put the turbo on; I'm guessing that the turbo feed is on the same gallery as where I tapped in for the pressure reading (using a mechanical gauge coming out the same place where the stock oil pressure gauge sender was)...in any event, 75K miles at those readings and all's well
To the OP, it looks like you already have a good answer, but for what it's worth, I see 10 psi at hot idle, and between 35 and 40 psi at freeway speeds. My pressure went down a bit after I put the turbo on; I'm guessing that the turbo feed is on the same gallery as where I tapped in for the pressure reading (using a mechanical gauge coming out the same place where the stock oil pressure gauge sender was)...in any event, 75K miles at those readings and all's well
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Fully warmed up mine runs 12 psi @ idle and 38-40psi running down the road. Don't matter if its 2500 rpm or 3800 rpm thats my max pressure. I'd prefer to see a little more at speed but even switching to 50wt oil didnt make any difference.
Andertusa
Full Access Member
I'm sorry that I did not use the 'Search' function, I've used the things elsewhere and found them to often be a 'service provided to no-one' in that often the 'search box' really doesn't search the website you are on or at as a reference, but instead redirects to third party sites, often advertising. I didn't use it because I didn't know it's veracity as a viable tool.
I am sorta 'new' here, I was on a while ago, did some posting, then took a hiatus due to circumstance, I honestly had no idea that this question had been asked so frequently as of late.
I will admit that I am a dreamer and I like to envision what I want to do to my trucks & cars. I often like to familiarize myself with the matters of things before I get started and until now iun my life, I've never really been 'familiar' with diesel engines, let alone the IDI ones, when I was growing up, the Powerstroke was the king, or it was the 5.9 Cummins, occasionally the GM diesels made the list, but I was never around these diesels. Until recently, my only mechanical interaction with a diesel was checking the oil and adding diesel to my work vehicle while AT work.
My trucks( two 1984 F350 RC DRW with 4-stick, one 'HD' long wheelbase) never came with any kind of manuals as I wasn't even close to the first or even second owners of them. I'm not the type to really try diving into a repair or build project without knowing what to do. I was raised to refer to those wiser than myself when I found/find myself at a loss, so I turn to you nice folks as most have done FAR MORE to their engines than I've even thought about.
Andertusa
Full Access Member
,To the OP, it looks like you already have a good answer, but for what it's worth, I see 10 psi at hot idle, and between 35 and 40 psi at freeway speeds. My pressure went down a bit after I put the turbo on; I'm guessing that the turbo feed is on the same gallery as where I tapped in for the pressure reading (using a mechanical gauge coming out the same place where the stock oil pressure gauge sender was)...in any event, 75K miles at those readings and all's well
Thank you for your reply, I was wondering because I was always under the impression that some diesels used the engine oil to 'pop open the injectors, well if that's the case, I would have thought the Oil pressure would be like HIGH, not a very gas-like 10-15psi.
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79jasper
Chickenhawk
That would be the powerstroke and one cat engine. But they still run a normal old oil pump with regular pressures, then some gets pumped to a high pressure oil pump where it gets ramped up to nearly 4000 psi, then to the injectors.
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Some diesels do use oil pressure to supply pop pressure to the injectors. These are described as "hydraulically actuated electronic unit injection" (HEUI) systems, and the 7.3L and 6.0L Powerstrokes are good examples of engines set up with HEUI; if memory serves, some variants of the DT466e also use HEUI, as do some Caterpillar engines (Cat designed the system). This was an early form of common-rail injection, allowing better control than the old setup that used a third camshaft lobe to pop the injector (which meant that timing couldn't be advanced as RPM's went up), but has since been technologically superceded by modern common-rail setups like what the '03+ Cummins, Duramax, and 6.7L PSD's use, which pop the injectors electronically.
The IDI does not use oil pressure to pop the injector; instead, there's a high-pressure injection pump that sends pulses of fuel to each injector when it's supposed to fire; when the pulse of high pressure reaches the injector, the injector pops open until pressure in the hard line goes down. It's a simpler system and uses much simpler injectors (the injectors on our engines are basically pop-nozzles), but it also utilizes a complex injector pump, and doesn't allow the fine-tuning of fuel injection events that common-rail systems do. FWIW the system the IDI has was very common between the 1950's and the late 1990's; the 6.2L/6.5L GM and the pre-'03 6BT Cummins used essentially the same system (the 6.2L even uses a different version of the same injector pump as the 6.9L/7.3L IDI; the later 6.5L and the 24 valve Cummins ISB use injector-pump-driven systems, but with an injector pump with electronic controls), as did earlier versions of the DT466, and even the smaller diesels by VW and Daimler-Benz.
One thing worth noting...even on the HEUI systems that rely on oil pressure to fire the injectors, there are essentially two oil systems. There's a low-pressure oil system that lubricates the engine, and there's a second high-pressure oil pump that pressurizes the oil lines going to the injectors. I don't know if the HPOP is electric or mechanical; someone who's messed with the newer engines could tell you more about it. But, hopefully that can give you a basic idea
Andertusa
Full Access Member
I knew some did that, I didn't think it was the IDIs, but I'm still pretty new to these beasts and haven't taken anything apart( on these trucks).
Nothing wrong with thatI knew some did that, I didn't think it was the IDIs, but I'm still pretty new to these beasts and haven't taken anything apart( on these trucks).
we all have to start somewhere, right?These engines are pretty simple...once the engine's running, the only electricity the engine needs is a low-amperage 12 volt signal to the fuel shut-off solenoid; otherwise, EVERYTHING is mechanical. No ECM to power or to go bad here
If you REALLY want to see an engine that will outlive cockroaches, the Mercedes OM61X engines are 100% mechanical, with a vacuum-powered shutoff valve. the only thing the engine needs electricity for is the starter. I drove an '85 300D from Los Angeles to the Bay Area (about 400 miles) with no alternator once
I was just careful to not shut it down, and did all of my traveling in daylight...Andertusa
Full Access Member
Sounds like a FUN weekend. 
sjwelds
Full Access Member
Reminds me of a story. Supposedly there was this guy with a Jeep. The Jeep had a manual transmission. He drove it from PA to Alaska and back with no starter. Before he'd shut off the engine, he always backed one rear wheel of the Jeep onto a wooden ramp, and then when it was time to go, why just pop-start the rig. As the story goes, he made it to within 50-100 miles of back home in PA, and then it failed to start. He had been carrying the starter with him, so he had to get out and install it to get home.
Me, I would have busted out the jack and reset the ramp. It'd sure make the story better
Probably wouldn't have worked with our high-compression IDI engines....
Me, I would have busted out the jack and reset the ramp. It'd sure make the story better
Probably wouldn't have worked with our high-compression IDI engines....
...I don't know if the HPOP is electric or mechanical; someone who's messed with the newer engines could tell you more about it. But, hopefully that can give you a basic idea
Tim,
The HPOP on the PSD's are a mechanical oil pump driven off the timing gear stack at the back of the engine. It is located in the valley, somewhat under the turbo........
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madpogue
Full Access Member
^^^^ No, it's not. The timing gears are on the FRONT of the engine, and the HPOP sits up front. Spatially, it takes place of the injection pump on our trucks. Like our IP, it's driven by the camshaft gear. Like our IP, it generates very high pressure. Unlike our IP, it pressurizes engine oil to be used hydraulically. And unlike our IP, it has no timing; it just pressurizes two common oil rails that then split off to each injector in the cylinder heads.
