5.7L HEMI - Oil Temperature / Engine Speed / Oil Pressure Correlation Table

[dman90]

Over the last several months I have been collecting and compiling the engine data of my 5.7L HEMI to create an oil temperature, engine speed, and oil pressure correlation table. The purpose of this endeavor is to create a baseline of performance for the OEM Mopar MO-339 filter. In the future I will be switching to a higher efficiency filter and want to assure there is no significant change in oil pressure from doing so. I am publishing this table in hopes it can help someone else. I cannot confirm these values are applicable to any engine besides my own, but I am looking for feedback. Please let me know how accurate these numbers are in relation to your HEMI engine.

Things of note...

All pressure values were obtained by recording many data points over a wide range of temperatures and engine RPM, then extrapolating any missing data and finally confirming/fine tuning the results. Despite my best efforts, due to slight variations in engine performance and the oil pressure display rounding to the nearest whole number, an accuracy of +/- 1 PSI is the best I could attain.

From my observations oil pressure follows a mostly linear trend line with the exception of at idle. Pressures at idle (600 RPM) drop off significantly as the oil temperature rises, decreasing at a substantially increasing rate above 158*F. I cannot seem to find explanation for this, however it does seem to give merit to the claim high idle hours contribute to the notorious cam and lifter failure theses engines experience.

The choice of colors does not indicate (good) or (bad) pressures, it was just for differentiating purposes.

The following values on the chart are estimates based strictly on extrapolation only,

• Pressures above 3,000 RPM and below 212*F due to potential damage from over-revving a cold engine.
• Pressures at 600 RPM (Idle) and below 104*F due to the ECU restricting low idle at colder temperatures.
• All pressures at oil temperatures above 218*F

 

[Bladecutter]

While it's an interesting chart, I'm not sure how you're supposed to prove what you hope to prove with the way that you are collecting your data. How are you collecting the temperature and pressure data? Are you using the PCM from the car to provide the sources of the data, or did you install your own oil pressure and oil temperature sensors to collect this data?

The oil filter you are testing is the exact same one my 2022 Stelvio has installed in it.

The problem:
The oil filter has a bypass valve built into it.

You have no true way of knowing at what point that bypass opens, and your engine oil filtration efficiency test becomes ineffective.

What you need is an actual test rig you can mount the oil filter to that can read the pressure entering the filter, and leaving the filter, so that you can see the change in pressure as the oil bypasses the filter media. Control the temperatures that the oil is, and you can control the pressures that are fed into the filter. That would be a much more reliable way to test an oil filter, and then you wouldn't have to take "worn engine" variables into the equation.

And I cringe at the thought of running a cold engine with 0F oil in it to 5500 rpms in order to get a pressure reading.
I probably don't want to know how you got the oil to 264F if you are using the PCM in the car to provide the data.

 

[dman90]

While it's an interesting chart, I'm not sure how you're supposed to prove what you hope to prove with the way that you are collecting your data. How are you collecting the temperature and pressure data? Are you using the PCM from the car to provide the sources of the data, or did you install your own oil pressure and oil temperature sensors to collect this data?

The oil filter you are testing is the exact same one my 2022 Stelvio has installed in it.

The problem:
The oil filter has a bypass valve built into it.

You have no true way of knowing at what point that bypass opens, and your engine oil filtration efficiency test becomes ineffective.

What you need is an actual test rig you can mount the oil filter to that can read the pressure entering the filter, and leaving the filter, so that you can see the change in pressure as the oil bypasses the filter media. Control the temperatures that the oil is, and you can control the pressures that are fed into the filter. That would be a much more reliable way to test an oil filter, and then you wouldn't have to take "worn engine" variables into the equation.

And I cringe at the thought of running a cold engine with 0F oil in it to 5500 rpms in order to get a pressure reading.
I probably don't want to know how you got the oil to 264F if you are using the PCM in the car to provide the data.

While it is true this may not be the best way of going about it, I was mostly interested in a way the average person could it. There will always be a better way of doing something but I don't think most people access to sophisticated, lab grade, engine pre/post oil filter monitoring equipment. For how I collected the oil pressure data, the vehicle has a digital readout in the gauge cluster, no scan tool needed. Yes, in regards to the bypass valve opening this data will not tell you that, however if you install a new higher efficiency filter, and notice a pressure drop across the board you can tell oil flow is being restricted. Also, as I mentioned in the post, pressure values below 212F at high RPMs are estimates, not actual numbers, as well as all pressures above 218F. They were extrapolated using existing data.

 

[twX]

From my observations oil pressure follows a mostly linear trend line with the exception of at idle. Pressures at idle (600 RPM) drop off significantly as the oil temperature rises, decreasing at a substantially increasing rate above 158*F. I cannot seem to find explanation for this, however it does seem to give merit to the claim high idle hours contribute to the notorious cam and lifter failure theses engines experience.

The reason for this is that the oil pump's relief valve is closed at low rpm when the oil is warm, but it's relieving pressure in all other operating conditions. The relief valve seems to be cracking open when the gallery pressure gets to around 46-48 psi.

Oil filter restriction should affect the oil pressure reading, but only really while the oil pump is in pressure relief, i.e. not at warm idle. The difference between two filters might not be much more than your measurement accuracy, but a clogged filter should cause a noticeable drop in oil pressure. Your data should be a good baseline for determining when an oil filter starts to clog.

In the interest of science, I think you should keep the same oil filter on the engine until there's a measurable drop in oil pressure. Then cut it open and dry out the media to see what filter media looks like when it's on the verge of becoming clogged.

 

[Plumb Bob]

Thanks for the data.
Anything that's not lab controlled is a wild guess. Too many variables.

 

[OVERKILL]

From my observations oil pressure follows a mostly linear trend line with the exception of at idle. Pressures at idle (600 RPM) drop off significantly as the oil temperature rises, decreasing at a substantially increasing rate above 158*F. I cannot seem to find explanation for this, however it does seem to give merit to the claim high idle hours contribute to the notorious cam and lifter failure theses engines experience.

That's perfectly normal behaviour when you consider the relationship between viscosity, volume, clearances and pressure. The oil pump is positive displacement and moves the least amount of oil at idle (volume). The hotter the oil is, the thinner it is, so the easier it's going to flow through the galleries and the lower the back pressure (oil pressure) is going to be. As soon as you change one of those variables: volume or viscosity (increase engine RPM to move more oil or make the oil thicker) the higher resistance presents as increased oil pressure.

High hours (idle or otherwise) is what ultimately exposes a defective lifter (reasonably common pre-2018) or poorly heat treated camshaft (the cams are SADI, not billet, which was a mistake). A vehicle that spends a ton of time tooling around at low speeds and idling will accrue far fewer miles relative to hours than one that spends most of its life on the highway, which will accrue far more miles relative to hours.

Roller lifters don't require large volumes of lubrication, which is why the lobes on modern roller motors aren't exposed to splash lube like they were on the old flat tappet mills.

This is an issue not only present with the HEMI, but also for the LSx/LTx engines and the Ford 7.3L Godzilla engine. Basically, all modern pushrod engines have experienced lifter failure. This is not unique to the HEMI. In fact, it is not even the most prolific manifestation, that title belongs to the GM engines with AFM (now DFM). And, like with the HEMI's, it's a crap shoot as to whether it's a variable displacement (AFM/DFM/MDS) lifter that packs it in, or a regular one.

The reason for this is that the oil pump's relief valve is closed at low rpm when the oil is warm, but it's relieving pressure in all other operating conditions. The relief valve seems to be cracking open when the gallery pressure gets to around 46-48 psi.

It shouldn't, the OE relief is 65psi, IIRC.

 

[twX]

It shouldn't, the OE relief is 65psi, IIRC.

The pressure at the sensor in the main gallery will be lower than it is at the valve in the oil pump.

Also, some oil pump PRV ratings aren't based on the actual cracking pressure of the valve, but instead the main gallery pressure that the valve will limit the pressure to at operating temperature. That's probably the case here since this happens to be around 65 psi.

 

[OVERKILL]

The pressure at the sensor in the main gallery will be lower than it is at the valve in the oil pump.

Yeah, due to the DP of the filter (pressure sensor is not far from the pump). There shouldn't be a 20psi differential though, as the media bypass in the filter isn't near that. Also keep in mind that he's noted that above 3,000RPM and below 212F, his figures are calculated, not measured:

The following values on the chart are estimates based strictly on extrapolation only,

• Pressures above 3,000 RPM and below 212*F due to potential damage from over-revving a cold engine.
• Pressures at 600 RPM (Idle) and below 104*F due to the ECU restricting low idle at colder temperatures.
• All pressures at oil temperatures above 218*F

Also, some oil pump PRV ratings aren't based on the actual cracking pressure of the valve, but instead the main gallery pressure that the valve will limit the pressure to at operating temperature. That's probably the case here since this happens to be around 65 psi.

I've recorded mine (SRT has the same 65psi relief):




Oil pressure appears to decouple from RPM at around 62-64psi. This is with a FRAM Ultra filter however, not the same filter the OP is using. My wife's truck behaves the same (I run the same filter).

 

[cptbarkey]

I would be more interested in your data on cam and lifter failures. Ancedotally I still see 2002-2005 ones clacking down the road on occasion so they arent dead like most of the 4.7 corpses.

I will also have to say, Hemi UOAs here are consistently the ugliest UOAs around, Blackstone labs will tell you "thats just the way the engine is." I still enjoyed the few I owned in the past and would probably consider a 6.4 in 2500+ in the future.

 

[OVERKILL]

I would be more interested in your data on cam and lifter failures. Ancedotally I still see 2002-2005 ones clacking down the road on occasion so they arent dead like most of the 4.7 corpses.

I will also have to say, Hemi UOAs here are consistently the ugliest UOAs around, Blackstone labs will tell you "thats just the way the engine is." I still enjoyed the few I owned in the past and would probably consider a 6.4 in 2500+ in the future.

Lifter failures started to happen around the time VCT was added to the engine (not MDS). I still see lots of early MDS ones around (2005, 2006, 2007, 2008...etc). Pretty much all of our 2011 and 2012 trucks (MDS, VCT) have had a lifter pack it in at around 200,000 miles (give or take, engine hours would all be similar).

I'm going to assume that all three marques (FCA, GM, Ford) are getting their roller lifters from the same supplier, because all three have had the same problem with lifter failure. I'm not sure if a supplier change happened around the time of the Daimler-Chrysler sale to FIAT, producing FCA and the addition of VCT, but it all seemed to start at around that period.

The FCA issue was compounded by the use of SADI cam cores, which just have surface hardening on the lobes, which means they don't tolerate any real degradation of the lobe surface. They start to come apart very quickly once the surface hardening is breached. The saving grace for FCA was that the HEMI MDS lifters aren't prone to failure like the GM AFM ones (which can collapse) so while GM used much better billet cam cores (and sometimes the cam survives a lifter failure, if it is caught early enough) the rate of GM lifter failure is higher.

Then of course Ford re-entered the pushrod scene with the 7.3L "Godzilla" engine, which immediately started having the same problem as FCA and GM with lifter failure.

The old Federal Mogul lifters from the 80's and 90's were bomb-proof (I've personally reused a set on multiple camshafts with like 200,000 miles on them and they were mint) so I'm not sure what happened here, whether it's a Ch-Ch-Ch CHINA! problem, Mexico, or something, but the combination of design issues and poor QC has lunched a lot of cams and junkyarded a lot of engines and vehicles.

HEMI UOA's always show high copper, that's normal for them. They also have a higher iron PPM per 1,000 miles than smaller engines, but aren't all that different from the GM LSx engine family in this respect. The old SBC's were even worse in this regard and I suspect it's just a byproduct of a large bore iron block V8 with a lot of swept ring area.

 

[4WD]

Lifter failures started to happen around the time VCT was added to the engine (not MDS). I still see lots of early MDS ones around (2005, 2006, 2007, 2008...etc). Pretty much all of our 2011 and 2012 trucks (MDS, VCT) have had a lifter pack it in at around 200,000 miles (give or take, engine hours would all be similar).

I'm going to assume that all three marques (FCA, GM, Ford) are getting their roller lifters from the same supplier, because all three have had the same problem with lifter failure. I'm not sure if a supplier change happened around the time of the Daimler-Chrysler sale to FIAT, producing FCA and the addition of VCT, but it all seemed to start at around that period.

The FCA issue was compounded by the use of SADI cam cores, which just have surface hardening on the lobes, which means they don't tolerate any real degradation of the lobe surface. They start to come apart very quickly once the surface hardening is breached. The saving grace for FCA was that the HEMI MDS lifters aren't prone to failure like the GM AFM ones (which can collapse) so while GM used much better billet cam cores (and sometimes the cam survives a lifter failure, if it is caught early enough) the rate of GM lifter failure is higher.

Then of course Ford re-entered the pushrod scene with the 7.3L "Godzilla" engine, which immediately started having the same problem as FCA and GM with lifter failure.

The old Federal Mogul lifters from the 80's and 90's were bomb-proof (I've personally reused a set on multiple camshafts with like 200,000 miles on them and they were mint) so I'm not sure what happened here, whether it's a Ch-Ch-Ch CHINA! problem, Mexico, or something, but the combination of design issues and poor QC has lunched a lot of cams and junkyarded a lot of engines and vehicles.

HEMI UOA's always show high copper, that's normal for them. They also have a higher iron PPM per 1,000 miles than smaller engines, but aren't all that different from the GM LSx engine family in this respect. The old SBC's were even worse in this regard and I suspect it's just a byproduct of a large bore iron block V8 with a lot of swept ring area.

Yep, and the plain Jane lifters have failed too - and then the switch hitters get blamed anyway …

 

[OVERKILL]

Yep, and the plain Jane lifters have failed too - and then the switch hitters get blamed anyway …

Yep, exactly. GM has two failure mechanisms with the lifters, while FCA has one. On the other hand, GM cams often survive, while FCA cams delaminating (the surface hardening coming apart) is another, albeit less common, failure mechanism.

 

[dman90]

Over the last several months I have been collecting and compiling the engine data of my 5.7L HEMI to create an oil temperature, engine speed, and oil pressure correlation table. The purpose of this endeavor is to create a baseline of performance for the OEM Mopar MO-339 filter. In the future I will be switching to a higher efficiency filter and want to assure there is no significant change in oil pressure from doing so. I am publishing this table in hopes it can help someone else. I cannot confirm these values are applicable to any engine besides my own, but I am looking for feedback. Please let me know how accurate these numbers are in relation to your HEMI engine.

Things of note...

All pressure values were obtained by recording many data points over a wide range of temperatures and engine RPM, then extrapolating any missing data and finally confirming/fine tuning the results. Despite my best efforts, due to slight variations in engine performance and the oil pressure display rounding to the nearest whole number, an accuracy of +/- 1 PSI is the best I could attain.

From my observations oil pressure follows a mostly linear trend line with the exception of at idle. Pressures at idle (600 RPM) drop off significantly as the oil temperature rises, decreasing at a substantially increasing rate above 158*F. I cannot seem to find explanation for this, however it does seem to give merit to the claim high idle hours contribute to the notorious cam and lifter failure theses engines experience.

The choice of colors does not indicate (good) or (bad) pressures, it was just for differentiating purposes.

The following values on the chart are estimates based strictly on extrapolation only,

• Pressures above 3,000 RPM and below 212*F due to potential damage from over-revving a cold engine.
• Pressures at 600 RPM (Idle) and below 104*F due to the ECU restricting low idle at colder temperatures.
• All pressures at oil temperatures above 218*F

View attachment 258678

Update. After collecting baseline data for the factory oil filter I switched to a high efficiency filter at my next oil change. The filter I used was the Fram Endurance

Over the last several months I have been collecting and compiling the engine data of my 5.7L HEMI to create an oil temperature, engine speed, and oil pressure correlation table. The purpose of this endeavor is to create a baseline of performance for the OEM Mopar MO-339 filter. In the future I will be switching to a higher efficiency filter and want to assure there is no significant change in oil pressure from doing so. I am publishing this table in hopes it can help someone else. I cannot confirm these values are applicable to any engine besides my own, but I am looking for feedback. Please let me know how accurate these numbers are in relation to your HEMI engine.

Things of note...

All pressure values were obtained by recording many data points over a wide range of temperatures and engine RPM, then extrapolating any missing data and finally confirming/fine tuning the results. Despite my best efforts, due to slight variations in engine performance and the oil pressure display rounding to the nearest whole number, an accuracy of +/- 1 PSI is the best I could attain.

From my observations oil pressure follows a mostly linear trend line with the exception of at idle. Pressures at idle (600 RPM) drop off significantly as the oil temperature rises, decreasing at a substantially increasing rate above 158*F. I cannot seem to find explanation for this, however it does seem to give merit to the claim high idle hours contribute to the notorious cam and lifter failure theses engines experience.

The choice of colors does not indicate (good) or (bad) pressures, it was just for differentiating purposes.

The following values on the chart are estimates based strictly on extrapolation only,

• Pressures above 3,000 RPM and below 212*F due to potential damage from over-revving a cold engine.
• Pressures at 600 RPM (Idle) and below 104*F due to the ECU restricting low idle at colder temperatures.
• All pressures at oil temperatures above 218*F

View attachment 258678

Update: After collecting baseline data for the factory Mopar oil filter, I switched to a high efficiency filter at my next oil change. The filter I used was the Fram Endurance FE10060 with an efficiency of 99% at 20 microns. The initial reduction in oil pressure across the table was 1-2 PSI new. After 300 miles the pressure reduction was 2-3 PSI below baseline. At 600 miles the oil PSI was 3-4 PSI lower than OEM, and at 900 miles the pressure loss was 4-5 PSI below that of the factory filter. Based on this trend of oil pressure reduction I discontinued using it. I experienced a loss of 15% nominal oil pressure at hot idle after just 900 miles. In addition, I noticed a longer than normal amount of time to build oil pressure after a startup. Based on this I am going to stick with the Mopar MO-339. It maintained consistent oil pressure over the entire oil change interval.

 

[twX]

The initial reduction in oil pressure across the table was 1-2 PSI new. After 300 miles the pressure reduction was 2-3 PSI below baseline. At 600 miles the oil PSI was 3-4 PSI lower than OEM, and at 900 miles the pressure loss was 4-5 PSI below that of the factory filter. Based on this trend of oil pressure reduction I discontinued using it. I experienced a loss of 15% nominal oil pressure at hot idle after just 900 miles.

If 15% is a 4-5 psi drop, it seems you did the comparison at warm idle. It would have been better to do the comparison at higher rpm, where the oil pressure doesn't change much with temperature. At warm idle, the oil pressure is very sensitive to oil temperature, and if the temperature is from an ECU algorithm instead of a sensor, it probably isn't very accurate. Do you have any oil pressure data with the Fram at higher rpm?

It's surprising that the oil pressure would drop so quickly. Typically, the restriction of oil filter media will hardly increase at all until the filter is loaded to over 50% of its holding capacity. I doubt that the gradual drop in oil pressure is related to the filter.

You introduced a new variable by changing the oil. Even if it was the same brand/grade of oil, it likely would've started out at a higher viscosity than the previous fill. Shear thinning and fuel dilution will thin the oil, and most of this happens in the first 1,000 miles or so. So the final test at 900 miles is probably most representative of the difference between the filters, assuming the pressure drop is actually due to the filter.

Did the oil pressure go back up after after you switched back to the Mopar filter? By how much?