OIL Weight?

[BOOT]

Has anyone ever compared different oil weights, not viscosity BUT actual mass?

Other factors of course like what one sticks/sheds more, nothing I'll be looking into myself just thought it was kinda interesting. Can't get all the oil off with a scrapper and a diff brand oil is cheaper than a dry sump.

[BOOT]

I mean it coats everything moving

[lefty o]

it coats everything moving is why thinner viscosity oils are run when it can be gotten away with. the thinner stuff gets off the moving parts faster. its physical mass isnt nearly as important as how fast the mass gets off what you dont want it on.

[BOOT]

it coats everything moving is why thinner viscosity oils are run when it can be gotten away with. the thinner stuff gets off the moving parts faster. its physical mass isnt nearly as important as how fast the mass gets off what you dont want it on.

That's obvious but some brands claim to protect/stick/adhere/coat better than other equal rated viscosity's

[BOOT]

Or lets talk about Zinc(ZDDP) contents role in total mass LOL

[RDY4WAR]

There's only 3 factors that determine the ideal viscosity: operating oil temperature, rod and main bearing clearance, and the load on those bearings.

Oil mass is irrelevant and not correlative with viscosity. There's 0w-20 oils that are .850 SpG and 20w-50 oils that are .830 SpG. Oils that contain a lot of ester or naphthalene (Red Line HP series, High Performance Lubricants HP Flush oil, Valvoline Premium Blue Restore, etc...) may get >.900 SpG, but they aren't common oils.

ZDDP has very little role in mass as well. ZDDP activates in boundary lubrication if sufficient heat and friction is present. It forms a tribofilm between the parts to prevent metal-to-metal contact. The higher the load or shear, the thicker the tribofilm needs to be. More ZDDP than necessary does nothing for wear protection, only increases the friction coefficient and oil acidity. Other additives in the oil, particularly friction modifiers, detergents, and viscosity modifiers, reduce ZDDP reactivity at low temperatures which is why an ideal break-in oil will very little or none of those additives.

The rod and main bearings operate only in full hydrodynamic lubrication so the oil viscosity, or rather dynamic viscosity, is key in that area. The pistons temporarily go into full hydrodynamic lubrication near peak piston speed in the stroke. Every other part of the engine operates in mixed or boundary lubrication where the oil viscosity means very little. In mixed and boundary lubrication, there is no oil film present so the anti-wear, friction modifier, and extreme pressure additives are carrying the load.

Oil cling is not relevant in an engine with a pressurized oiling system. All cling gets you is increased fluid friction, more stress on the pump and filter, and (in worst case) make oil linger where it shouldn't and solidify into sludge. Lucas Oil Stabilizer is a heavy polymer with a tackifier in it (and no other additives) so it'll cling to those gimmicky plastic gears to deceive you into thinking that's somehow relevant to an engine. Aside from the bearings, every other part of the engine sees mixed and boundary lubrication where the oil viscosity and clinginess means nothing. Clinginess or tackiness is only relevant in non-pressurized systems where the oil must track up the gears such as manual transmissions and rear gears / differentials. Even then, it should be limited.

[MELWAY]

Bryce

In reference to the clinginess of the oil
What about in a flat tappet cam the sits for a long time between starts?
I pulled down engines where the cam looks really dry with some oils
And on other hand seen engines on Pennsylvania base oils where cams look to have oil clinging to them after a year of not starting
That makes me feel better about no dry start on flat tappet cam until oil splash can get there

[Mark O'Neal]

About 2 lbs per quart can, including the can...

[BOOT]

Bryce

In reference to the clinginess of the oil
What about in a flat tappet cam the sits for a long time between starts?
I pulled down engines where the cam looks really dry with some oils
And on other hand seen engines on Pennsylvania base oils where cams look to have oil clinging to them after a year of not starting
That makes me feel better about no dry start on flat tappet cam until oil splash can get there

Prob also depends on climate somewhat, for example there was post on here I think where they guy pull the valvecovers and it looked corroded or coated and it was dried oil I guess, think it was a real dry place. I've always found stuff plenty oily many yrs later.

Now I bought a reman crate and it was nice an oily but just a few months later and it all rusted up, Areas you could see coated in oil like the lifter valley. Must of been REAL crappy oil cause I've left a engine on a stand a few feet away with no intake covered with an engine bag for maybe a decade and it's fine.

[RDY4WAR]

Bryce

In reference to the clinginess of the oil
What about in a flat tappet cam the sits for a long time between starts?
I pulled down engines where the cam looks really dry with some oils
And on other hand seen engines on Pennsylvania base oils where cams look to have oil clinging to them after a year of not starting
That makes me feel better about no dry start on flat tappet cam until oil splash can get there

The lifter/lobe interface operates in boundary lubrication so there's no substantial oil film present. ZDDP is doing all of the work. The AW tribofilm is very thin and often times is chemically bonded with the metal. It may appear dry, but if you were to run ICP on the lobe surface, you'd find a bunch of zinc, phosphorus, and sulfur.

Pennsylvania crude is highly polar which is why the oil film wants to linger around. It's also why you don't want it to get too hot or run it for long intervals. That high polarity also helps drive additive activation, particularly at lower temperatures. It's why group I base oils work so well in turbines.

[David Redszus]

The Sommerfeld Number correlates closely to the coefficient of friction in the
bearing. As oil viscosity, speed, bearing diameter and length increase, so does
the S value. As bearing clearance, temperature and load increase, the S value
decreases. A lower S value will produce a lower coefficient of friction.

Up to a point. That point is a S value of approximately .005 at which friction is
minimized. Below that value we leave the fluid film lubrication regime and enter
the very dangerous boundary lubrication zone. This is where metal to metal
contact is ever present and the bearing will quickly self-destruct.

By entering the viscosity properties of candidate oils, temperature and operating
conditions, it is possible to determine which oil viscosity will provide the required
viscosity necessary to produce maximum power and yet adequately protect
the engine from destruction.

The actual inputs required are:
Journal diameter
Bearing clearance
Bearing speed
Bearing load
Bearing length
*Vis at 40c and 100c
*Temperature
*Specific gravity
*required to determine actual viscosity at point of lubrication

Whether or not a candidate oil has adequate EP or anti-wear additives is much less important
than correct engineering design for the application.

[MadBill]

...Up to a point. That point is a S value of approximately .005 at which friction is minimized. Below that value we leave the fluid film lubrication regime and enter
the very dangerous boundary lubrication zone. This is where metal to metal
contact is ever present and the bearing will quickly self-destruct....

Did you mean 0.0005" David, or are you going metric on us?

[David Redszus]

...Up to a point. That point is a S value of approximately .005 at which friction is minimized. Below that value we leave the fluid film lubrication regime and enter
the very dangerous boundary lubrication zone. This is where metal to metal
contact is ever present and the bearing will quickly self-destruct....

Did you mean 0.0005" David, or are you going metric on us?

You may use either the metric or Imperial unit system since the Sommerfeld Number is dimensionless.
It is a coefficient.

[MadBill]

...Up to a point. That point is a S value of approximately .005 at which friction is minimized. Below that value we leave the fluid film lubrication regime and enter
the very dangerous boundary lubrication zone. This is where metal to metal
contact is ever present and the bearing will quickly self-destruct....

Did you mean 0.0005" David, or are you going metric on us?

You may use either the metric or Imperial unit system since the Sommerfeld Number is dimensionless.
It is a coefficient.

Ah, yes: just as you posted yesterday!

[Cobra720]

There's only 3 factors that determine the ideal viscosity: operating oil temperature, rod and main bearing clearance, and the load on those bearings.

Oil mass is irrelevant and not correlative with viscosity. There's 0w-20 oils that are .850 SpG and 20w-50 oils that are .830 SpG. Oils that contain a lot of ester or naphthalene (Red Line HP series, High Performance Lubricants HP Flush oil, Valvoline Premium Blue Restore, etc...) may get >.900 SpG, but they aren't common oils.

ZDDP has very little role in mass as well. ZDDP activates in boundary lubrication if sufficient heat and friction is present. It forms a tribofilm between the parts to prevent metal-to-metal contact. The higher the load or shear, the thicker the tribofilm needs to be. More ZDDP than necessary does nothing for wear protection, only increases the friction coefficient and oil acidity. Other additives in the oil, particularly friction modifiers, detergents, and viscosity modifiers, reduce ZDDP reactivity at low temperatures which is why an ideal break-in oil will very little or none of those additives.

The rod and main bearings operate only in full hydrodynamic lubrication so the oil viscosity, or rather dynamic viscosity, is key in that area. The pistons temporarily go into full hydrodynamic lubrication near peak piston speed in the stroke. Every other part of the engine operates in mixed or boundary lubrication where the oil viscosity means very little. In mixed and boundary lubrication, there is no oil film present so the anti-wear, friction modifier, and extreme pressure additives are carrying the load.

Oil cling is not relevant in an engine with a pressurized oiling system. All cling gets you is increased fluid friction, more stress on the pump and filter, and (in worst case) make oil linger where it shouldn't and solidify into sludge. Lucas Oil Stabilizer is a heavy polymer with a tackifier in it (and no other additives) so it'll cling to those gimmicky plastic gears to deceive you into thinking that's somehow relevant to an engine. Aside from the bearings, every other part of the engine sees mixed and boundary lubrication where the oil viscosity and clinginess means nothing. Clinginess or tackiness is only relevant in non-pressurized systems where the oil must track up the gears such as manual transmissions and rear gears / differentials. Even then, it should be limited.

Interesting information. Is there anything to higher viscosity holding air in suspension and causing hydraulic lifter issues like compression or higher viscosity without air in suspension helping a lifter at high RPMs. ??