Let the debate continue

[Shannow]

Neither flow nor pressure lubricate, it's the interaction of moving surfaces and the oil between them.

The DP along the oil galleries is small enough to ignore except at the limits of pumpability...any temp that we see in Australia, just about anything at SCA is not going to be a problem...40-70 is probably an exception, it's a silly thing to be on the shelves.

The oil pressure IS the artifact of the pump supplying more pressure than the engine is consuming. Bearings can create a negative pressure and suck oil in from ambient if needed. Excess capacity is required to maintain supply as things age and wear.

Oil squirters rely on pressure to operate, and cam phasers are an area that Honda have identified as potentially at risk when oil pressure drops with lower viscosities.

It's not ideal the oil pump being in relief, as it wastes energy...difference between 60 and 80 psi and 4gpm is about 50W, so inconsequential if you drive with your headlights on during the day.

It's still a power waster, and OEMs are putting in variable volume oil pumps to not burn that wattage.

But contrary to popular posit, you don't have to jam a sump's full of oil through the bearings, they draw off what they need from the galleries.

 

[B320i]

Thanks for the response, Shannow. That provided the clarification I was looking for.

I take it your stance is to follow the manufacturer's suggestion based on the expected temperature, or just choose an oil that falls somewhere along the chart?
My query from that small paragraph above would be if the bearings (for example) really care what oil they are drawing in so long as they can?

 

[Shannow]

Here's a pic that I really like, showing the oil flow rates versus HTHS on an operating engine that they isolated a single main bearing, and provided oil at a constant pressure...it demonstrates that the bearings pull oil from the supply.

My preference is to pick an appropriate HTHS, then get a "W" grade that's appropriate for your cold start conditions. My choice is usually 3.5 min (A3/B4), and here in Lithgow, I could run anything up to a 20W with zero issues.

But I prefer synthetic, and there's no Synthetic 20W, 15W, or 10W 30s around with A3/B4, so I use 5W30.

Would and have used 5W40s (three 20L drums of Magnatec SP have run through my shed), and have used a fair bit of 0W40 (Mobil and Castrol). But personally, I'd rather not have uber high VI that shears down to a target, but something that sits more in the middle.

Edge A3/B4 is my go to at the moment.

I'm not one for dropping the HTHS in cold weather, as messing with my Caprice, if I hold it in "2" for 10km at 100km/h (4,000RPM), the oil temperature can hit 135C, even mid winter...it's extreme and for giggles/science, but if I put in a 20 basing the choice on my commute and ambient, and then had a funeral to attend 800km away, I want the HTHS to be there when needed.

Just on that, I'd run a 20W20 in the Caprice if I could find one SJ, SL or up...not having polymers in them, they run 2.9HTHS, same as an ILSAC 5W30.

 

[tig1]

Originally Posted By: Shannow
Firstly, flow doesn't provide lubrication (101 is wrong there).

On start-up, if the W grade of the oil is appropriate for the conditions, the galleries will be filled at the same time regardless.

So at my place, there would be no real difference between a 0W, 5W, 10W, or 15W anything at getting the oil galleries filled, and pressure to the system.

With the system primed, the thicker oils will have less oil flow to the bearings etc. and more through the relief, as the bearings draw oil off the pressurised galleries only what they need to replace their side leakage.

Less flow just means that the bearings need less oil, not that they aren't lubricated as well.

The wear occurs when the galleries are full, and the oil is flowing, and the engine isn't up to temperature...Industry standard Sequence IV the engine is running, the oil is flowing, just the temperatures are controlled to the point that the viscosity protection is dropping, but the additives aren't functional...that's where the wear takes place.


I was referring to the upper end of an engine, not the bearings, where flow makes a difference. I found that out in the 70s when I lived in Maine. In sub zero temps the Valvoline 10-40 I used caused the lifters(77Chevy 305) to clatter very bad on cold start, as well as very slow cranking. In 1978 I changed to M1 5-20 and it was like night and day. No lifter noise, and cranking speed increased dramatically.

 

[BrocLuno]

Originally Posted By: Shannow
The stuff that they say about film thickness and viscosity is correct.

The stuff that they say about a thin oil offering less margin in an overheat is correct.

The stuff that they say about possibly needing a higher viscosity for certain activities that generate heat is correct.

The tone of the article is scaremongering.


+1 on all points !!

And 101 on flow is absolutely wrong and misleading. Grab your oil can a put a drop on a bolt (no flow) and it IS lubricated. You can turn it on and off a 100 times, and unless it has been wiped clean (no oil) the lubrication is still there.

That flow statement is an absolute credibility killer for 101. Edit it and get it right.

The presence of oil, in sufficient quantities, from any source (gravity, splash, pressure fed, etc.) is what lubricates - period.

 

[demarpaint]

Originally Posted By: tig1
Originally Posted By: Shannow
Firstly, flow doesn't provide lubrication (101 is wrong there).

On start-up, if the W grade of the oil is appropriate for the conditions, the galleries will be filled at the same time regardless.

So at my place, there would be no real difference between a 0W, 5W, 10W, or 15W anything at getting the oil galleries filled, and pressure to the system.

With the system primed, the thicker oils will have less oil flow to the bearings etc. and more through the relief, as the bearings draw oil off the pressurised galleries only what they need to replace their side leakage.

Less flow just means that the bearings need less oil, not that they aren't lubricated as well.

The wear occurs when the galleries are full, and the oil is flowing, and the engine isn't up to temperature...Industry standard Sequence IV the engine is running, the oil is flowing, just the temperatures are controlled to the point that the viscosity protection is dropping, but the additives aren't functional...that's where the wear takes place.


I was referring to the upper end of an engine, not the bearings, where flow makes a difference. I found that out in the 70s when I lived in Maine. In sub zero temps the Valvoline 10-40 I used caused the lifters(77Chevy 305) to clatter very bad on cold start, as well as very slow cranking. In 1978 I changed to M1 5-20 and it was like night and day. No lifter noise, and cranking speed increased dramatically.


I noticed the same thing back in the day, and once I started using M1 5W30 it stopped.

 

[Shannow]

Originally Posted By: tig1
Originally Posted By: Shannow
Firstly, flow doesn't provide lubrication (101 is wrong there).

On start-up, if the W grade of the oil is appropriate for the conditions, the galleries will be filled at the same time regardless.

So at my place, there would be no real difference between a 0W, 5W, 10W, or 15W anything at getting the oil galleries filled, and pressure to the system.

With the system primed, the thicker oils will have less oil flow to the bearings etc. and more through the relief, as the bearings draw oil off the pressurised galleries only what they need to replace their side leakage.

Less flow just means that the bearings need less oil, not that they aren't lubricated as well.

The wear occurs when the galleries are full, and the oil is flowing, and the engine isn't up to temperature...Industry standard Sequence IV the engine is running, the oil is flowing, just the temperatures are controlled to the point that the viscosity protection is dropping, but the additives aren't functional...that's where the wear takes place.


I was referring to the upper end of an engine, not the bearings, where flow makes a difference. I found that out in the 70s when I lived in Maine. In sub zero temps the Valvoline 10-40 I used caused the lifters(77Chevy 305) to clatter very bad on cold start, as well as very slow cranking. In 1978 I changed to M1 5-20 and it was like night and day. No lifter noise, and cranking speed increased dramatically.


Again, you are talking about the MRV and CCS...at the limits of pumpability which is what I keep saying. A 5W50 would have provided the same effect, in spite of being thicker KV40 and KV100.

A 5W20 provides no increase in "flow" to the valvetrain at temperatures around freezing...nil

Per the API
http://www.api.org/~/media/Files/Certification/Engine-Oil-Diesel/Publications/MOM_GUIDE_ENGLISH_2013.pdf

sub zero, they recommend 0W and 5W oils...

 

[Gokhan]

Originally Posted By: Jake777
If you feel so inclined check out this brief article and share your thoughts.

http://www.machinerylubrication.com/Read/518/motor-oils

So what do you think? Generally an exceptable premise?

Note that it's a highly outdated, thirteen-year-old article. Motor-oil AW/EP/FM technology that allows thinner oils has improved and it's still on a path to tremendously improve with the GF-6 technology on the horizon.

This is not to say that everyone should run xW-20 or even xW-16/xW-12/xW-8 but thinner oil is not necessarily bad for protecting against wear, depending on the application and oil certification. Your oil pump, engine-block parts, and valvetrain parts need to be designed for thinner oil and the operating and load conditions shouldn't be too severe.

 

[B320i]

Originally Posted By: Shannow
Originally Posted By: tig1

I was referring to the upper end of an engine, not the bearings, where flow makes a difference. I found that out in the 70s when I lived in Maine. In sub zero temps the Valvoline 10-40 I used caused the lifters(77Chevy 305) to clatter very bad on cold start, as well as very slow cranking. In 1978 I changed to M1 5-20 and it was like night and day. No lifter noise, and cranking speed increased dramatically.


Again, you are talking about the MRV and CCS...at the limits of pumpability which is what I keep saying. A 5W50 would have provided the same effect, in spite of being thicker KV40 and KV100.

A 5W20 provides no increase in "flow" to the valvetrain at temperatures around freezing...nil

Per the API
http://www.api.org/~/media/Files/Certification/Engine-Oil-Diesel/Publications/MOM_GUIDE_ENGLISH_2013.pdf

sub zero, they recommend 0W and 5W oils...


The article quoted says the following
Quote:
Multigrade oils such as SAE 5W-30 and 10W-30 are widely used because, under all but extremely hot or cold conditions, they are thin enough to flow
at low temperatures and thick enough to perform satisfactorily at high temperatures. Note that vehicle requirements may vary

 

[CT8]

Originally Posted By: tig1
Originally Posted By: Shannow
Firstly, flow doesn't provide lubrication (101 is wrong there).

On start-up, if the W grade of the oil is appropriate for the conditions, the galleries will be filled at the same time regardless.

So at my place, there would be no real difference between a 0W, 5W, 10W, or 15W anything at getting the oil galleries filled, and pressure to the system.

With the system primed, the thicker oils will have less oil flow to the bearings etc. and more through the relief, as the bearings draw oil off the pressurised galleries only what they need to replace their side leakage.

Less flow just means that the bearings need less oil, not that they aren't lubricated as well.

The wear occurs when the galleries are full, and the oil is flowing, and the engine isn't up to temperature...Industry standard Sequence IV the engine is running, the oil is flowing, just the temperatures are controlled to the point that the viscosity protection is dropping, but the additives aren't functional...that's where the wear takes place.


I was referring to the upper end of an engine, not the bearings, where flow makes a difference. I found that out in the 70s when I lived in Maine. In sub zero temps the Valvoline 10-40 I used caused the lifters(77Chevy 305) to clatter very bad on cold start, as well as very slow cranking. In 1978 I changed to M1 5-20 and it was like night and day. No lifter noise, and cranking speed increased dramatically.
The killer in sub zero temps is too thick oil will not be drawn into the oil pump for a long period of time if maybe not at all. So a thinner conventional/thinner syn oil would be prudent.