Hot oil pressure with M1 0w20- video

[440Magnum]

95 degree day, truck driven for over an hour, city/highway combo driving. Idle oil pressure ~25 plus, but still pushing >70 at 2000 RPM and peaking over 80 at the (limited in neutral) 4000. Dodge Ram 1500 310-horse 4.7L SOHC v8, 19,000 miles.

Video link

In short, I wouldn't go thicker on this engine. PS- note that the dash oil pressure gauge is an idiot gauge- doesn't move a peg. Hence the dashtop gauge... ;-)

 

[oilboy123]

Wow I saw 440 and M1 0w-20 and thought what a trailblazer........

That's some healthy pressure. Is the aftermarket gauge electric sender or tubing?

 

[justinf89]

That's a pretty nice gauge how it moves so freely. I've been thinking about some kind of setup myself in my explorer. It's got the same [censored] non-moving type lol. Same with the thermostat.

85psi is pushing it in my opinion but then again, I wouldn't want to go lower than 20. I can't believe a 20 weight is pushing 80. I assume the truck was fully warmed up (oil not motor temp)?

 

[SEMI_287]

I have the same numbers in my 4.7 with 174k miles.

I have M1 5w20 in her right now. The 4.7 is a fantastic motor.

 

[needsducktape]

So what does this all mean? -Have you tried other weights ?

 

[oilboy123]

Maybe the newer engines are designed to have that real high pressure? I guess I'm used to the old V-8s of yesteryear.....

 

[sittingduck57]

The old rule was 10 psi per 1000 rpm. depending on where you are tapping in at you could possibly have a restriction somewhere or if you have areation of the oil you could get a false high

 

[ARB1977]

AFE 0W30 in my Tacoma was 50 psi hot. Now that I'm HM 5W30 Mobil One its now 45 paid hot. Never thought thinner oil would create higher pressure.

 

[440Magnum]

It a mechanical gauge (capillary tube). I haven't tried anything except 5w20 and 0w20 in that engine, and the engine had been run most of the morning so the oil was hot (though maybe not quite as hot as if I'd just exited the freeway). The gauge has only been installed a little while. I put it on because I'm going to use the truck for some towing and wanted to have a better idea of the pressures and whether a grade thicker would be appropriate or not. I'm going to get it really good and hot with a few highway runs and see how things look before even thinking about thicker oil.

I've been reading the service manual on the 4.7, and even though it doesn't have MDS or anything like that, just the way some of it is made I think it really needs the thin oil. It runs high pressure. The timing chains are lubricated by spray from small orifices in the tensioners, by jets on the intermediate timing gear, and by spray from oil pump shaft leakage. Thicker oil wouldn't spray as effectively, and I have to wonder if some of the early problems with 4.7s back in 2000 to 2001 were due to people running thicker oil.

 

[daman]

Sounds like your on the right track with the viscosity your using,one thing i may add is with them small orifices for spray lubrication I'd stick with a synthetic to combat sludge tarnish/deposits that could plug the galleys,just my thought.

 

[SEMI_287]

Not to mention the 4.7 oil pressure tap is after the filter so it's so the gauge is pretty accurate for pressure in the rest of the motor.

 

[440Magnum]

Originally Posted By: SEMI_287
Not to mention the 4.7 oil pressure tap is after the filter so it's so the gauge is pretty accurate for pressure in the rest of the motor.


As are all modern Mopars, AFAIK. The old big-blocks actually had the oil pressure port at the back end of the galley system farthest from the oil feed, so that the indicated pressure was what the last (#5) main and cam bearings saw.

 

[mechtech2]

That seems awful high for a real hot day and a 20.
But tapping in right after the filter may be why.

 

[Gokhan]

Originally Posted By: 440Magnum
95 degree day, truck driven for over an hour, city/highway combo driving. Idle oil pressure ~25 plus, but still pushing >70 at 2000 RPM and peaking over 80 at the (limited in neutral) 4000. Dodge Ram 1500 310-horse 4.7L SOHC v8, 19,000 miles.

Video link

In short, I wouldn't go thicker on this engine. PS- note that the dash oil pressure gauge is an idiot gauge- doesn't move a peg. Hence the dashtop gauge... ;-)

I hope you find this helpful:

(1) There are no hydrostatically lubricated parts in an engine; so, the oil pressure is not that critical in lubrication as long as you have sufficient pressure, and the manufacturers specify a wide range of acceptable oil pressure. In a hydrostatically lubricated system, oil pressure would be what prevents metal-to-metal contact.

(2) Bearings are hydrodynamically lubricated, which means that you will have bearing failure at one point if you run a too thin viscosity, even though your oil pressure is sky high. Oil viscosity is what prevents metal-to-metal contact in a hydrodynamically lubricated system, not the oil pressure.

Therefore, going thinner than what the manufacturer recommends is quite risky, especially if you drive hard or do towing. I don't know what is recommended for your engine.

Perhaps if you drive gently -- gentle acceleration, gentle throttle, no towing, etc., resulting in light loads on the bearings -- a thinner viscosity is OK. Also, fuel economy benefits of thinner viscosity are most pronounced for gentle driving.

 

[wiswind]

I did not see the year listed on the truck,.....I did a lookup on 2008 Ram 1500 with the 4.7L on the Amsoil website....and it seems that 5W-20 and 0W-20 is what is recommended for this motor for both the normal and the flex-fuel versions.
From reading other posts by the OP, I think he would have mentioned it if he were using other than the specified oil for this vehicle.
Seems 2006 called for xW-30 and 2007 called for xW-20 with the 4.7L motor....from the listings on the Amsoil and Redline websites.

 

[steve20]

I have s soft spot for that motor as well--

 

[440Magnum]

Originally Posted By: wiswind
I did not see the year listed on the truck,.....I did a lookup on 2008 Ram 1500 with the 4.7L on the Amsoil website....and it seems that 5W-20 and 0W-20 is what is recommended for this motor for both the normal and the flex-fuel versions.
From reading other posts by the OP, I think he would have mentioned it if he were using other than the specified oil for this vehicle.
Seems 2006 called for xW-30 and 2007 called for xW-20 with the 4.7L motor....from the listings on the Amsoil and Redline websites.


Yes, its a 2008, running the RECOMMENDED 20-wt oil. Did a long highway run today, and the pressures didn't change from the video.

Given the fact that oil flow is important to cooling things like the timing chain guides and that it has PLENTY of pressure on 20wt, I see absolutely no reason at all to deviate from factory recommendations. The whole fear of 20wt oils is, to me, unfounded and this engine bears it out. Going thicker would unnecessarily raise the oil pressure, and since the chain guide tension is maintained by oil pressure it would just unnecessarily raise the chain tension and grind away the guide faces too.

 

[wiswind]

I think folks were concerned that you were using xW-20 in a motor that called for xW-30.
I must be having a special day to have guessed the exact year.

 

[modularv8]

Originally Posted By: 440Magnum
Originally Posted By: SEMI_287
Not to mention the 4.7 oil pressure tap is after the filter so it's so the gauge is pretty accurate for pressure in the rest of the motor.


As are all modern Mopars, AFAIK. The old big-blocks actually had the oil pressure port at the back end of the galley system farthest from the oil feed, so that the indicated pressure was what the last (#5) main and cam bearings saw.


Generally, engines designed to run on 20wt have different shaped main bearings (less bearing bleed-off) and operate at higher pressures on the main bearings (60+ psi @ 2k rpms, operating temp) with pressure reduction (metered orifice)through the cam bearings and hydraulic chain adjusters. So these pressures are not unusual. The Ford 5.4L 3v operates at 75 psi through the main bearings.

 

[440Magnum]

Originally Posted By: modularv8
Originally Posted By: 440Magnum
Originally Posted By: SEMI_287
Not to mention the 4.7 oil pressure tap is after the filter so it's so the gauge is pretty accurate for pressure in the rest of the motor.


As are all modern Mopars, AFAIK. The old big-blocks actually had the oil pressure port at the back end of the galley system farthest from the oil feed, so that the indicated pressure was what the last (#5) main and cam bearings saw.


Generally, engines designed to run on 20wt have different shaped main bearings (less bearing bleed-off) and operate at higher pressures on the main bearings (60+ psi @ 2k rpms, operating temp) with pressure reduction (metered orifice)through the cam bearings and hydraulic chain adjusters. So these pressures are not unusual. The Ford 5.4L 3v operates at 75 psi through the main bearings.


Which is basically my point... the fear of Xw20 that keeps cropping up is unfounded, and even in hard use there's not much (if any) reason to run these engines on heavier oil. They're made for a 20-wt, and there are disadvantages to going thicker.