Adjust oil pressure 472 -Update

[RobW]

20W-50 is recommended in the owner's manual for the temp ranges I drive in. The way I understand viscosity ratings is the oil will flow as a 20W in cold weather and up to a 50W in higher heat.

[RobW]

so this is from my 73 owner's manual. looks like 10W-40 is only recommended up to 60* ?

[Jon S]

so this is from my 73 owner's manual. looks like 10W-40 is only recommended up to 60* ?

Yup. In the 1950's 10w/40 didn't exist and 10w/30 was the standard. I changed to 10w/40 in the 1980's. I would recommend staying away from 50w oil unless your car burns oil.

[Scot Minesinger]

Jon,

Same for me switched to 10W40 in 80's

[TJ Hopland]

so this is from my 73 owner's manual. looks like 10W-40 is only recommended up to 60* ?

But notice how it and 10w-30 also listed on the top line with the 20w stuff too?    It kinda looks like 10w-40 was the magic oil of the 70's, it could do anything. 

[Bobby B]

Yup. In the 1950's 10w/40 didn't exist and 10w/30 was the standard. I changed to 10w/40 in the 1980's. I would recommend staying away from 50w oil unless your car burns oil.

20w-50 is pretty thick stuff.   If you are going to run that you have to make sure you only run it when its hot.   Cool temps that stuff is going to not flow well and be really hard on things.    Mid summer it may not be bad but you get some of those spring and fall days you got to be careful even down south.    If you want to get freaked out you should feel the drag on an oil pump running 5w-30 at 70*F,  that takes a fair amount of power.  Going 4x thicker can be a good thing.

According to Dr. Haas, the "W" in oil stands for "Winter" not "Weight" ....... Without getting into heavy detail, oil in the 50 range will only cause drag, rob your engine of power, and cause all sorts of components to work harder than they need to. Most cars don't run above 212 degrees, so there is no need to run 50 oil anymore, as the above posts stated. If you check the specs on oil, 40 is way more than enough for a normal car on a very hot day. The first number is more important anyway, as 90% of engine wear to any occurs on start up, weather hot or cold.
Using oil with a viscosity that is too high can result in excessive oil temperature and increased drag. Using an oil with a low viscosity can lead to excessive metal to metal contact between moving parts. Using the correct viscosity oil eases starting, reduces friction and slows wear which also means less drain on your battery, starter, alternator, etc. Engines that run low oil temps require lower viscosity oil. Looser clearances in the engine and oil pump require higher viscosity oil to maintain oil pressure. Tighter clearances need lower viscosity oil, which provides better cooling and improved horsepower.
The relationship between pressure and flow is in opposition. If you change your oil to a thicker formula the pressure will go up. It goes up because the resistance to flow is greater and in fact the flow must go down in order for the pressure to go up. They are inversely related. Conversely if you choose a thinner oil then the pressure will go down. This can only occur if the flow has increased.
It's partly true that you should be using the thinnest oil money can buy. The gold standard is that all engines should have a pressure of 10 PSI for every 1,000 RPM of operation, not more, not less. You need some pressure to move that oil along, but only enough pressure, not more. More pressure is not better, it can only result from the impedance of oil flow. Remember that oil flow is the only thing that does the lubricating. High flow does more than lubricate. It is one of the things used to cool the hottest parts of your engine, the pistons, valve areas and bearings. This cooling effect is as important as lubrication in your engine. If your engine is running hot you may need to use a thinner oil. The flow will increase and so will the cooling. I have no problems running 10W-30 in all the old cars with some ZDDP.
                                                                                                      Bobby

[RobW]

OK, I'm due for an oil change anyway. I'll try 10W-40 and see how it goes.

[chrisntam]

Our '06 (Toyota) uses 5w20.  Now that's shocking.

[TJ Hopland]

I think Ford was one of the first domestics to start 5w-20 in the mid to late 90's I think.   Early 2000's they came out with a bulletin saying they recommended using it in just about everything back to the late 80's that called for 5w-30.   I had a 05 Dodge that used it and had to buy Ford oil because Chrysler only sold it in 55 gallon drums at the time.   I notice it pretty much pours the same  from 0*F to 150*F out of a hot engine.     

[Jon S]

The 5W/20 is used on my Mustang also and as the engine tolerances got tighter, lighter weight oils were recommended.  Also, the lighter weight oil improved MPG ratings and provide superior lubrication with the tighter tolerances.

[TJ Hopland]

More flow for cooling is an aspect I had not thought of.  I suppose piston squirters are getting to just be part of a typical engine design nowadays.   

[Jeff Rosansky CLC #28373]

Ok boys and girls. It appears to be pressure related.
Put in ZDDP and went for a long drive. About 35-40 miles, ac on, 90 degrees. When first starting out, pressure was upper 40's. When hot and thin, mid 20's at hiway speeds which matches the 10psi per thousand mentioned earlier.... However at idle it was reading 0ish.
Oil light was not on. Now I must point out the gauge pickoff is at that plug just above the oil pump. I assume (hope) this is at the end of the run so pressure at the main switch would still be hi enough to keep it from closing.
As noted above, 10-40 with a new engine. When I put my foot on the gas and get it to 800 rpm or so the pressure comes up to about 10. It is just at the 450-500 idle that I have nothing.
How do I bump up the idle pressure?
Jeff

[The Tassie Devil(le)]

The only place to take the oil pressure readings from is the port that the electric sender taps into, at the back of the block.

This way you are getting a true pressure, as measured by the engineers.

Bruce.

[Scot Minesinger]

Jeff,

Right below the alternator and above oil pump is where I tapped in for oil pressure readings at the plug.  I'm using a standard stock oil pump and a real good Autometer gauge where transducer at sensor send signal by wire (no oil in dash).  This is where I get my readings:  25 to 28 at idle, 37 at about the highest.  Given that my engine was rebuilt 39k miles and eleven years ago I'm good with these readings.

I have done this on other 472/500 engines and always got a good reading.

If your getting zero reading there that is no good.

I replaced my oil sensor for dash warning light because it was leaking.

[Jeff Rosansky CLC #28373]

Yes, that is exactly where I have it. That odd plug that goes in at about a 5 degree angle. I also have an electric one because I dont want oil lines in the cabin.
I get the same readings you do when the oil is thick but was surprised tgey were that low after it was really hot.
So, how do I bump it up?
Jeff

["Cadillac Kid" Greg Surfas 15364]

Jeff,
If your gage is correct and the oil  pressure  taken off the main primary passage above the oil pump is that low you have a serious problem and should not operate the motor.  That point is right off the pump and is the MOST pressure in the system.
Again if the gage is correct I would suspect oil pump issues and if this were mine I would pull and inspect the pump. The bypass spring might be broken or the valve itself might be binding.
THE PLUG ON THE MAIN OIL GALLERY IS NOT THE PLACE TO TAKE PRESSURES IF YOU ARE GOING TO COMPARE THEM TO THE FACTORY NUMBERS.  As Bruce says, the rear tap where the pressure sensor/oil light switch is installed is the correct location.
Greg Surfas

[Jeff Rosansky CLC #28373]

Am I able to access that spring with the pump still on the car? The pump is new ( I know about new parts). If the spring is bad I may just be able to replace it easily.
What kind if issues will I have pulling and replacing the pump? I have the manual on my phone (thanks to my kid) so it doesnt look too bad but there are always tricks. Will that oil pump drive shaft fall out? If so will it just slide back in and engage with the distributor with a slite tweek of course? Or is there a trick to engaging it? If the pump seats fully then is the driveshaft correct?
I still have my old pump. I may just throw it back on if it isnt too bad of a job. Would be great if I can do that easily in the morning and then drive it to get my donut by 8am.
Jeff

["Cadillac Kid" Greg Surfas 15364]

Jeff,
Follow the manual.  I am not sure if the oil pump drive shaft will clear out the bottom, but I would suggest if you are going to work on the pump, remove it and inspect all the internals.  When you reinstall it pack the pump cavity with Vaseline and be sure the new gasket has  absolutely clean mating surfaces on the block and the pump.
Greg Surfas

[chrisntam]

When I pulled my pump, I also pulled the dizzy so I could prime the system after I reinstalled the pump (I'm frightened of a dry start up).  I did use petroleum jelly (Vaseline) for packing the pump.  I think I used 1/2" wobble socket with an extension to get to the oil pump bolts.

I'd put the gauge at the back of the engine to see what you get before you go monkeying with the oil pump.

Wouldn't the engine clatter or rattle if the oil pressure was too low?  And would the low oil pressure light come on?

["Cadillac Kid" Greg Surfas 15364]

Chris,
Check the gage first, then try it at the port in the rear where the oil pressure switch goes.
Greg Surfas