Anyone Have Genuine Mopar 440 Oil Pressure Numbers?

[Bruzilla]

I'm looking for some genuine, published, Mopar oil pressure numbers for 440 engines. Cold, warm, hot - idle, curb idle, above 1,200 RPM - 10W30-10W40. I'm not looking for "I get this on my engine...", just actual numbers from the historical writings.

 

[lewtot184]

there probably isn't any actual published numbers. pressure will vary a little due to different factors. but, if it's any help the 440 4bbl had a red 45psi spring. i believe '70-'71 6paks used a black 65psi street hemi relief spring.

 

[oldbee]

Well the old FSM only says 20psi@500rpm & 45-65@1000. If you have a red spring you could always do like I did & put a regular old lock washer(5/16"?) behind the spring. Oh, the Hemi shows 15psi@500rpm!!

 

[lewtot184]

i remember my '68 road runner, 383 4spd, always having a steady 45psi. I used a lot of 30wt Valvoline back then. didn't seem to make much difference hot or cold. same pump as a 440, half groove mains like a 440, same rod bearings, etc.

 

[69a100]

Well the old FSM only says 20psi@500rpm & 45-65@1000. If you have a red spring you could always do like I did & put a regular old lock washer(5/16"?) behind the spring. Oh, the Hemi shows 15psi@500rpm!!

I would go with this about the FSM Bru, I don't know how more concrete info you want then that? With what your asking, It makes me want to ask why, what's up?

 

[mopar 3 B]

Original info would only be good if nothing had changed in 50 years.
All fossil products have changed and our engines were not designed for them. Every one wants to run low viscity synthetics designed for low clearemce engines in their old sloppy clearence engines.
Pressure reading will not be the same as they once were.

 

[Cornpatch MO]

Original info would only be good if nothing had changed in 50 years.
All fossil products have changed and our engines were not designed for them. Every one wants to run low viscity synthetics designed for low clearemce engines in their old sloppy clearence engines.
Pressure reading will not be the same as they once were.

Another good reason for me not to use synthetic................MO

 

[miller]

Yeah, I've got the 45lb. red spring in my 440 pump, and that's what I get at idle. But, no road time (yet), though still good when up to temp. Only using VR1 30 wt, on break in, going to 40 wt, after 500 miles.
Oil pressure you get depends alot on engine clearances, besides spring used, and oil wt.
Since when are these things meant to run on multi wt oil? I will now duck!

 

[Bruzilla]

I would go with this about the FSM Bru, I don't know how more concrete info you want then that? With what your asking, It makes me want to ask why, what's up?

Nothing major. I hooked up my old mechanical oil pressure gauge and on start up it reads a steady 45 or so PSI with 10W40, then after it gets hot it drops to about 25 PSI at curb idle and back up to 40-45 at above 1,000 or so RPM, all of which seems pretty normal to me. What I find interesting is that at either 45 or 25 PSI, the Rallye oil gauge stays at the exact same spot, the first line. I had always thought the gauge was an actual gauge, but it appears to be an idiot light.

Anyway, I went looking through some forums yesterday to try to find out what the factory says the pressure readings should be, and saw page after page of "Well, my engine gets..." posts that are totally worthless, and as a result there are guys out there telling folks crap like getting 80 PSI is normal. There are also guys telling people they need to tear apart their engines because they see a pressure drop when the engine gets hot! They're saying "Bad bearings!!!" and seem to have no clue that oil thins as it gets hot and requires much less pressure to flow!

I just wanted to find some actual numbers to start spreading around. Seems like most of the Mopar engine books cite a range of 20 PSI at hot idle to 80 PSI at WOT as being the edges of the performance envelope.

 

[miller]

Being honest about it...as far as what the manual tells you...two things. One is 'if' all the clearances on the build are in normal, by the book, limits. Two is the oil pump relief spring, if it's still in spec, is going to give the baseline oil pressure.
There 'might' be oil pressure limits, but it's the build, and oil used, that give you what pressure you get. If not enough...have to add more spring.

 

[Daves69]

.........it reads a steady 45 or so PSI with 10W40, then after it gets hot it drops to about 25 PSI at curb idle and back up to 40-45 at above 1,000 or so RPM.............

So are you saying the mechanical gauge gives you a max of 45 even when at cold start up or does it go higher? A hot engine at idle with 10w-40 and 25 psi pressure sounds pretty sane to me.

the Rallye oil gauge stays at the exact same spot, the first line. I had always thought the gauge was an actual gauge, but it appears to be an idiot light.

Dash gauges rely on the sensor sensitivity. Maybe there's something is up with that.

The MP book is basic at best........

Even old manuals such as this conveyed just general numbers. These were for '69........

 

[69a100]

That's weird that Fords are all over the place as well as GM's. Mopar must have had their squat together to have a constant 55 across the board.

 

[Bruzilla]

So are you saying the mechanical gauge gives you a max of 45 even when at cold start up or does it go higher? A hot engine at idle with 10w-40 and 25 psi pressure sounds pretty sane to me.

The mechanical gauge reads 45 PSI at start up with the engine cold. And that's with 10W-40. The electrical Rallye gauge reads on the first line. As the engine warms, and the oil thins, the pressure drops to about 25 at idle and then goes up to 45 or so as you increase RPM, and the electric gauge reads at the first line no matter what.

So what I think is that electric gauge is actually acting as a decision engine (pressure is there/pressure is not) and not as an actual quantitative gauge. This makes sense to me as if 45 PSI is the norm at start up, if the pressure drops by about 50% as the engine warms, the electric gauge would look like pressure was close to zero if it was acting as a gauge and owners would freak out.

 

[Daves69]

Not sure but I'm thinking if you short the dash gauge wire to ground momentarily (don't just hold it there), the needle should try to peg all the way over. This might be a quick check for the gauge sweep functions.
The stock dash gauge on my Barracuda follows the pressure difference of the mechanical albeit slower. Possibly your sensor is faulty.

At 45 psi cold start with higher rpm seems a bit weak though. I'd be curious what the heavier relief spring could do for it.

 

[Bruzilla]

Not sure but I'm thinking if you short the dash gauge wire to ground momentarily (don't just hold it there), the needle should try to peg all the way over. This might be a quick check for the gauge sweep functions.
The stock dash gauge on my Barracuda follows the pressure difference of the mechanical albeit slower. Possibly your sensor is faulty.

At 45 psi cold start with higher rpm seems a bit weak though. I'd be curious what the heavier relief spring could do for it.

A faulty sensor is always possible, but what's the odds it would fail in way that puts the gauge exactly at normal operation? I would say slim to none.

 

[beanhead]

Bruzilla I think you're on the right track that the factory gauge isn't meant to give a real-time PSI reading...in my truck the oil gauge has graduations on it but as soon as the engine starts the needle centers and stays there, no matter the engine's temp or RPM, whether under any load or not, even though we know that pressure fluctuates some under these conditions...

 

[Daves69]

.............I would say slim to none.

How do you know unless you're open to investigating.

 

[dvw]

The factory gauge has a narrow band sweep for a reletivly wide sweep of pressure. That coupled with various oil viscosity and internal clearance variations will show that there never was or ever will be a hard and fast number.
Doug

 

[lewtot184]

those old electric gauges never were quick to react to changes. if the mech gauge says 45psi with stock components that's about right. a straight weight oil may not fluctuate as much but 25psi hot idling in gear isn't bad for unknown bearing clearances. i'd try a straight 30wt.

 

[Bruzilla]

How do you know unless you're open to investigating.

Because 30+ years of experience has taught me there's rarely coincidences in this hobby. If something happens, it 99% of the time happens for a reason.