We finally got some... 0W-8.

[kschachn]

Is there anything about oil pressure creates a distance in the bearings in all this writing? Piston rings, that’s a lot different. I use what the cap says, it’s a lot less to read.

Pressure never lubricated a bearing.

 

[ZeeOSix]

I don’t see anything that appears incorrect in your post, which leads to a point I’ve made before: it’s really a matter of emphasis. This is why I have resorted to the perhaps sloppy (at least scientifically sloppy) “tastes great, less filling” metaphor. As with those long ago arguing beer drinkers, the real “argument” is about what we are emphasizing. Sure, a 0w-20 may theoretically protect better than an oil of lower vis, but in the real world, will it make a meaningful difference? Stripped to its barest essence, if Oil A, which according to tribological science, protects an engine “better” than Oil B, but does so in a way and to a degree such that it has no practical impact upon the service life of the vehicle, does it really matter in the end whether an owner chooses A or B? For some, it will, and that’s fine. I’m unconcerned about using the recommended 0w-8 in my car, but do plan to try the 0w-16 at some point soon, just to see if I can discern any observable differences in the car’s behavior. I will remain open minded about the possibilities.

It's about adding wear protection, and it's so simple to do ... just pour it in. The "recommended" viscosity in the USA (mostly driven by CAFE goals) is the thinnest the engineers would go with. It's meant to achieve more fuel mileage and still give a decent amount of engine life. If you could ask the engineers what viscosity they would recommend if CAFE wasn't involved, I highly doubt it would be the same, unless it was already xW-30 or higher. Just look at the oil viscosity shown in the OMs for the same engines used elsewhere in the world where CAFE is ignored. At least the Ford engineers finally won that battle with the 2021 and beyond Coyote in the USA, and now specify 5W-30 for it. It should have been specified from the beginning like the Coyote engineers wanted in the first place during development. Many 2011-2020 Coyote owners bump up to 5W-30 (or even higher) and never looked back.

 

[Fair enough]

If the oiling system can't provide an adequate volume of oil to the required parts, then it's an oiling system design issue (like not getting adequate volume to all bearings), not a viscosity used issue unless the wrong W grade is used in very cold weather conditions. Cold start pumpability (the W grade) is way more important when doing very cold start-ups than the KV100 used when and engine is at operating temperature. That why the same engine can tolerate xW-20 to xW-50 or 60. But use the wrong W grade and starve the engine of oil volume and you'll be asking for problems.

I always understood oil pressure keeps the bearings separated, not only static oil film, hence the question. Engine bearings and journals are designed to a specific size so there is a gap, like .001” or something. The oil pressure in the small gap is high and supports the weight of the surfaces trying to contact each other, not touching.

 

[ZeeOSix]

I always understood oil pressure keeps the bearings separated, not only static oil film, hence the question. Engine bearings and journals are designed to a specific size so there is a gap, like .001” or something. The oil pressure in the small gap is high and supports the weight of the surfaces trying to contact each other, not touching.

No, the supporting oil film is created from the journal bearing rotating. The oil could be feed into the bearing under the force of gravity (0 gauge pressure), and the oil film that supports the bearing in motion will still be produced and the bearing is in full hydrodynamic lubrication. The real time viscosity inside the bearing, the rotation speed and the load on the bearing will determine the resulting MOFT. If the MOFT goes to zero, wear occurs. Goal is to always keep the MOFT above zero. Journal bearings are pretty soft, and somewhat "sacrificial" if there is inadequate lubrication.

The oil pressure doesn't add enough support to really matter. The oil pressure is produced when the pump is sized to ensure enough oil volume is supplied (force fed) to the bearing accounting for side leakage and maybe some cooling effect so the bearings don't lack supply volume to ensure adequate lubrication. There's lots of info on the 'net on how journal bearings actually work.

 

[Fair enough]

No, the supporting oil film is created from the journal bearing rotating. The oil could be feed into the bearing under the force of gravity (0 gauge pressure), and the oil film that supports the bearing in motion will still be produced and the bearing is in full hydrodynamic lubrication. The real time viscosity inside the bearing, the rotation speed and the load on the bearing will determine the resulting MOFT. If the MOFT goes to zero, wear occurs. Goal is to always keep the MOFT above zero.

The oil pressure doesn't add enough support to really matter. The oil pressure is produced when the pump is sized to ensure enough oil volume is supplied (force fed) to the bearing accounting for side leakage and maybe some cooling effect so the bearings don't lack supply volume to ensure adequate lubrication. There's lots of info on the 'net on how journal bearings actually work.

I did read an article, it had this to say. The rest agrees with what you said. So O-8 or 16 oils recommended are based on the engine construction. So it may not be good to use thicker oils these engines. In the article he says some about bearing oil spread, last sentence in first quote. This supports the low viscosity oil use. Not that I agree or disagree.

“The larger the bearing, the broader the area over which the load is distributed. The smaller the bearing, the more concentrated the load is over a given portion of the bearing. Tightening up the bearing clearances and using lower viscosity oil helps distribute the load over a broader area of the bearing.”

“Regardless what type of bearings are used in an engine, clearances have to be precise and correct for the oil viscosity that will be used to lubricate the motor. Thin, low viscosity motor oils require tighter bearing clearances than heavier viscosity racing oils such as 20W-50 or straight 40, 50 or 60 weight oils.

Here are some recommended rod bearing oil clearances for various oil viscosities:

.0015 to .0018 for 5W-20 or 20W

.002 to .0024 for 5W-30 or 30W

.0025 to .0029 for 10W-40 or 40W

.0030 to .004 for 20W-50 or 50W

.0041 to .005 for 10W-60 or 60W”

Article:

https://www.tomorrowstechnician.com/engine-bearings-under-pressure/

 

[Revving2Redline]

People say a thinner oil gets in the bearing quicker. I used a thicker oil as it leaves the bearing slower. With low tension rings, DI, and boost i dont have any faith with a thin oil. Boutique oil of no less than maybe 0w30 and 5w30 for everyone else.

 

[Revving2Redline]

I did read an article, it had this to say. The rest agrees with what you said. So O-8 or 16 oils recommended are based on the engine construction. So it may not be good to use thicker oils these engines. In the article he says some about bearing oil spread, last sentence in first quote. This supports the low viscosity oil use. Not that I agree or disagree.

“The larger the bearing, the broader the area over which the load is distributed. The smaller the bearing, the more concentrated the load is over a given portion of the bearing. Tightening up the bearing clearances and using lower viscosity oil helps distribute the load over a broader area of the bearing.”

“Regardless what type of bearings are used in an engine, clearances have to be precise and correct for the oil viscosity that will be used to lubricate the motor. Thin, low viscosity motor oils require tighter bearing clearances than heavier viscosity racing oils such as 20W-50 or straight 40, 50 or 60 weight oils.

Here are some recommended rod bearing oil clearances for various oil viscosities:

.0015 to .0018 for 5W-20 or 20W

.002 to .0024 for 5W-30 or 30W

.0025 to .0029 for 10W-40 or 40W

.0030 to .004 for 20W-50 or 50W

.0041 to .005 for 10W-60 or 60W”

Article:

https://www.tomorrowstechnician.com/engine-bearings-under-pressure/

Interesting. Wonder how that all works in Yellowknife or even Edmonton at - 50. Im sure the oil will most likely thicken up, but will the tolerance be acceptable for the clearance? Does this also account for a car sitting at idle in NYC taking 3 hours to go four blocks? What kinda oil change monitoring system and is it set to severe oci?
Im gonna have to see what Europe is going to use as oil options before i complety buy into this, but i will at least hear them out.

 

[ZeeOSix]

I did read an article, it had this to say. The rest agrees with what you said. So O-8 or 16 oils recommended are based on the engine construction. So it may not be good to use thicker oils these engines. In the article he says some about bearing oil spread, last sentence in first quote. This supports the low viscosity oil use. Not that I agree or disagree.

“The larger the bearing, the broader the area over which the load is distributed. The smaller the bearing, the more concentrated the load is over a given portion of the bearing. Tightening up the bearing clearances and using lower viscosity oil helps distribute the load over a broader area of the bearing.”

“Regardless what type of bearings are used in an engine, clearances have to be precise and correct for the oil viscosity that will be used to lubricate the motor. Thin, low viscosity motor oils require tighter bearing clearances than heavier viscosity racing oils such as 20W-50 or straight 40, 50 or 60 weight oils.

Here are some recommended rod bearing oil clearances for various oil viscosities:

.0015 to .0018 for 5W-20 or 20W

.002 to .0024 for 5W-30 or 30W

.0025 to .0029 for 10W-40 or 40W

.0030 to .004 for 20W-50 or 50W

.0041 to .005 for 10W-60 or 60W”

Article:

https://www.tomorrowstechnician.com/engine-bearings-under-pressure/

Keep in mind that Ford says the Coyote can run anything from xW-20 to xW-50 ... and the bearing clearance is the same in all of them, and the bearing clearance is pretty tight. The Coyote rod bearings are at 0.0011 to 0.0027 inch and the crank bearings are at 0.0010 to 0.0018 inch. Those are right out of the factory service manual.

Based on this info from King Bearing (all they do is design journal bearings), the larger the bearing clearance, the worse a thinner oil will perform, but tight bearings (which is what most normal cars on the road have, and haven't changed for decades) can tolerate thin to thick oils, and a thicker oil will always result in more MOFT in a tighter bearing, but not in a much looser bearing. This has all been hashed over dozens of times in many threads here over the years. The post linked below sums up the effect of MOFT as a function of bearing clearance and oil viscosity. Bottom line is that thicker oil gives more MOFT in looser bearings than thinner oil, but thicker oil will give more MOFT even in tighter bearings. So bearings with more clearance are more sensitive to the viscosity used ... you don't want thinner oil in loser bearings. But mass produced vehicle engines have pretty tight journal bearings that can tolerate a large range of oil viscosity (like the Coyote example). Per the graph below, using a 0W-20 in bearings with over 0.002" clearance will not give as much MOFT. But using thicker oil will give more MOFT over the whole bearing clearance range. Also, if journal bearings are too tight, the oil will heat up so much inside the bearing that it will eventually fail.

Post in thread 'Are thinner oils about fuel economy or tighter engines?'

May 26, 2023

When it comes to lubricants viscosity, there are several important aspects of engines to consider. As mentioned before here, one of the main challenges lies in refining surface roughness and reducing bearings clearance.
Over time, clearances have generally decreased, with German engines holding no particular disadvantage over American or Japanese motors in this regard (Why they need more viscosity?? Please abstain from expounding upon temperature, for the question served but a rhetorical purpose.)

As mentioned many times in these type of discussions, the clearances between moving...

• ZeeOSix

• 

 

[Revving2Redline]

 

[kschachn]

I did read an article, it had this to say. The rest agrees with what you said. So O-8 or 16 oils recommended are based on the engine construction. So it may not be good to use thicker oils these engines. In the article he says some about bearing oil spread, last sentence in first quote. This supports the low viscosity oil use. Not that I agree or disagree.

“The larger the bearing, the broader the area over which the load is distributed. The smaller the bearing, the more concentrated the load is over a given portion of the bearing. Tightening up the bearing clearances and using lower viscosity oil helps distribute the load over a broader area of the bearing.”

“Regardless what type of bearings are used in an engine, clearances have to be precise and correct for the oil viscosity that will be used to lubricate the motor. Thin, low viscosity motor oils require tighter bearing clearances than heavier viscosity racing oils such as 20W-50 or straight 40, 50 or 60 weight oils.

Here are some recommended rod bearing oil clearances for various oil viscosities:

.0015 to .0018 for 5W-20 or 20W

.002 to .0024 for 5W-30 or 30W

.0025 to .0029 for 10W-40 or 40W

.0030 to .004 for 20W-50 or 50W

.0041 to .005 for 10W-60 or 60W”

Article:

https://www.tomorrowstechnician.com/engine-bearings-under-pressure/

What would give you that impression? You essentially invalidate that with your subsequent text.

 

[kschachn]

Keep in mind that Ford says the Coyote can run anything from xW-20 to xW-50 ... and the bearing clearance is the same in all of them, and the bearing clearance is pretty tight. The Coyote rod bearings are at 0.0011 to 0.0027 inch and the crank bearings are at 0.0010 to 0.0018 inch. Those are right out of the factory service manual.

Based on this info from King Bearing (all they do is design journal bearings), the larger the bearing clearance, the worse a thinner oil will perform, but tight bearings (which is what most normal cars on the road have, and haven't changed for decades) can tolerate thin to thick oils, and a thicker oil will always result in more MOFT in a tighter bearing, but not in a much looser bearing. This has all been hashed over dozens of times in many threads here over the years. The post linked below sums up the effect of MOFT as a function of bearing clearance and oil viscosity. Bottom line is that thicker oil gives more MOFT in looser bearings than thinner oil, but thicker oil will give more MOFT even in tighter bearings. So bearings with more clearance are more sensitive to the viscosity used ... you don't want thinner oil in loser bearings. But mass produced vehicle engines have pretty tight journal bearings that can tolerate a large range of oil viscosity (like the Coyote example). Per the graph below, using a 0W-20 in bearings with over 0.002" clearance will not give as much MOFT. But using thicker oil will give more MOFT over the whole bearing clearance range. Also, if journal bearings are too tight, the oil will heat up so much inside the bearing that it will eventually fail.

Post in thread 'Are thinner oils about fuel economy or tighter engines?'

May 26, 2023

When it comes to lubricants viscosity, there are several important aspects of engines to consider. As mentioned before here, one of the main challenges lies in refining surface roughness and reducing bearings clearance.
Over time, clearances have generally decreased, with German engines holding no particular disadvantage over American or Japanese motors in this regard (Why they need more viscosity?? Please abstain from expounding upon temperature, for the question served but a rhetorical purpose.)

As mentioned many times in these type of discussions, the clearances between moving...

• ZeeOSix

• 

View attachment 250821

Yes it has been hashed out dozens of times in many threads over the years. And with this poster in particular, despite yet another new user name. The circle just keeps going.

 

[tolian21]

What about Australia oil recommendations for this engine? If they allow for thicker oils in other parts of the world, why Toyota does this if its not good for engine?

 

[Fair enough]

Keep in mind that Ford says the Coyote can run anything from xW-20 to xW-50 ... and the bearing clearance is the same in all of them, and the bearing clearance is pretty tight. The Coyote rod bearings are at 0.0011 to 0.0027 inch and the crank bearings are at 0.0010 to 0.0018 inch. Those are right out of the factory service manual.

Based on this info from King Bearing (all they do is design journal bearings), the larger the bearing clearance, the worse a thinner oil will perform, but tight bearings (which is what most normal cars on the road have, and haven't changed for decades) can tolerate thin to thick oils, and a thicker oil will always result in more MOFT in a tighter bearing, but not in a much looser bearing. This has all been hashed over dozens of times in many threads here over the years. The post linked below sums up the effect of MOFT as a function of bearing clearance and oil viscosity. Bottom line is that thicker oil gives more MOFT in looser bearings than thinner oil, but thicker oil will give more MOFT even in tighter bearings. So bearings with more clearance are more sensitive to the viscosity used ... you don't want thinner oil in loser bearings. But mass produced vehicle engines have pretty tight journal bearings that can tolerate a large range of oil viscosity (like the Coyote example). Per the graph below, using a 0W-20 in bearings with over 0.002" clearance will not give as much MOFT. But using thicker oil will give more MOFT over the whole bearing clearance range. Also, if journal bearings are too tight, the oil will heat up so much inside the bearing that it will eventually fail.

Post in thread 'Are thinner oils about fuel economy or tighter engines?'

May 26, 2023

When it comes to lubricants viscosity, there are several important aspects of engines to consider. As mentioned before here, one of the main challenges lies in refining surface roughness and reducing bearings clearance.
Over time, clearances have generally decreased, with German engines holding no particular disadvantage over American or Japanese motors in this regard (Why they need more viscosity?? Please abstain from expounding upon temperature, for the question served but a rhetorical purpose.)

As mentioned many times in these type of discussions, the clearances between moving...

• ZeeOSix

• 

View attachment 250821

I know using precise cone bearing lathes, plain bearings, oil viscosity and how much heat generated is very noticeable. The whole headstock will get hot with a thicker oil, versus not with a thin oil. First hand experience. The graph is extreme in that10w 60 and 0w 20 are far apart, and what is the temperature.
It could be Toyota supplies engines with tighter bearing clearances for where they recommend 0w 8 or 16. Like the USA, it’s a big supply of engines and it could be they do that. With the benefit of less friction in the bearings for maximizing efficiency.
A Toyota engine may have tighter tolerances and clearances than the Coyote, which seems more like old times clearance ranges. Probably Ford has equal capability to any company, if they so choose, to make tighter tolerances and less clearance. Like .001” +/- .0002”or something. Of course an engine goes from cold to hot so everything expands and contracts.

 

[OVERKILL]

I know using precise cone bearing lathes, plain bearings, oil viscosity and how much heat generated is very noticeable. The whole headstock will get hot with a thicker oil, versus not with a thin oil. First hand experience. The graph is extreme in that10w 60 and 0w 20 are far apart, and what is the temperature.
It could be Toyota supplies engines with tighter bearing clearances for where they recommend 0w 8 or 16. Like the USA, it’s a big supply of engines and it could be they do that. With the benefit of less friction in the bearings for maximizing efficiency.
A Toyota engine may have tighter tolerances and clearances than the Coyote, which seems more like old times clearance ranges. Probably Ford has equal capability to any company, if they so choose, to make tighter tolerances and less clearance. Like .001” +/- .0002”or something. Of course an engine goes from cold to hot so everything expands and contracts.

The problem is that when it's -40, even 0W-8 is 10's of thousands of cSt, this is why engines can't be that picky, because the range of viscosity is huge, due to the impact of ambient temperature.

The Coyote clearances are pretty "typical", the reason clearances haven't changed in decades is because this spec "works" for all anticipated ambient conditions with a wide range of appropriate lubricants.

Like the Coyote having spec'd both 5W-20 and 5W-50, the 6.4L and 5.7L FCA engines spec 0W-40 and 0W-20 with the same clearances, this is due to both CAFE and anticipated operating conditions.

 

[wpod]

I know it has been discussed before and I know the thicker=better train of thought is outdated, but at some point viscosity for the sake of fuel economy has to be compromising wear. I'm not an expert by any stretch of the imagination but common sense would dictate this has to be the case. Maybe in most driving situations it would be fine, but what about high load, high temp conditions?

Thicker is better is not outdated.

 

[OVERKILL]

https://static.nhtsa.gov/odi/tsbs/2024/MC-10252251-9999.pdf

 

[Fair enough]

Keep in mind that Ford says the Coyote can run anything from xW-20 to xW-50 ... and the bearing clearance is the same in all of them, and the bearing clearance is pretty tight. The Coyote rod bearings are at 0.0011 to 0.0027 inch and the crank bearings are at 0.0010 to 0.0018 inch. Those are right out of the factory service manual.

Based on this info from King Bearing (all they do is design journal bearings), the larger the bearing clearance, the worse a thinner oil will perform, but tight bearings (which is what most normal cars on the road have, and haven't changed for decades) can tolerate thin to thick oils, and a thicker oil will always result in more MOFT in a tighter bearing, but not in a much looser bearing. This has all been hashed over dozens of times in many threads here over the years. The post linked below sums up the effect of MOFT as a function of bearing clearance and oil viscosity. Bottom line is that thicker oil gives more MOFT in looser bearings than thinner oil, but thicker oil will give more MOFT even in tighter bearings. So bearings with more clearance are more sensitive to the viscosity used ... you don't want thinner oil in loser bearings. But mass produced vehicle engines have pretty tight journal bearings that can tolerate a large range of oil viscosity (like the Coyote example). Per the graph below, using a 0W-20 in bearings with over 0.002" clearance will not give as much MOFT. But using thicker oil will give more MOFT over the whole bearing clearance range. Also, if journal bearings are too tight, the oil will heat up so much inside the bearing that it will eventually fail.

Post in thread 'Are thinner oils about fuel economy or tighter engines?'

May 26, 2023

When it comes to lubricants viscosity, there are several important aspects of engines to consider. As mentioned before here, one of the main challenges lies in refining surface roughness and reducing bearings clearance.
Over time, clearances have generally decreased, with German engines holding no particular disadvantage over American or Japanese motors in this regard (Why they need more viscosity?? Please abstain from expounding upon temperature, for the question served but a rhetorical purpose.)

As mentioned many times in these type of discussions, the clearances between moving...

• ZeeOSix

• 

View attachment 250821

To finish, for me, I would like to go back to oil pressure. I know splash lube is an oiling mechanism. You are saying 0 psi is still ok. I think we all know 1 psi is not going to work well in an engine. There will be bearing knock. Psi is good for the pistons if there jets but otherwise I think it’s splash. I know I read somewhere decades ago oil pressure in the bearing separates the parts. The hydrodynamic pumping still functions, but also there is considerable oil pressure in the narrow bearing opening. At 50 psi at gauge port I am guessing the main bearing pressure could be ten times that. Or is gauge port pressure due to main bearing resistance? It’s not clear about the oil pressure raising the psrts. Nothing changes, I still will go by the cap, although I think I was in the heavier oil brigade because of start up rattle.

 

[Fair enough]

The problem is that when it's -40, even 0W-8 is 10's of thousands of cSt, this is why engines can't be that picky, because the range of viscosity is huge, due to the impact of ambient temperature.

The Coyote clearances are pretty "typical", the reason clearances haven't changed in decades is because this spec "works" for all anticipated ambient conditions with a wide range of appropriate lubricants.

Like the Coyote having spec'd both 5W-20 and 5W-50, the 6.4L and 5.7L FCA engines spec 0W-40 and 0W-20 with the same clearances, this is due to both CAFE and anticipated operating conditions.

The car makers using 0w-8 and16 don’t allow for the heavier grades in the USA though like the Ford engine does. Toyota says can use 0 20 but change back to 0 16 at next change or as soon as possible, not sure of exact wording.

 

[kschachn]

The car makers using 0w-8 and16 don’t allow for the heavier grades in the USA though like the Ford engine does. Toyota says can use 0 20 but change back to 0 16 at next change or as soon as possible, not sure of exact wording.

Car makers don't "allow" grades they recommend them. And in this case it isn't based on anything technical or mechanical.

 

[kschachn]

To finish, for me, I would like to go back to oil pressure. I know splash lube is an oiling mechanism. You are saying 0 psi is still ok. I think we all know 1 psi is not going to work well in an engine. There will be bearing knock. Psi is good for the pistons if there jets but otherwise I think it’s splash. I know I read somewhere decades ago oil pressure in the bearing separates the parts. The hydrodynamic pumping still functions, but also there is considerable oil pressure in the narrow bearing opening. At 50 psi at gauge port I am guessing the main bearing pressure could be ten times that. Or is gauge port pressure due to main bearing resistance? It’s not clear about the oil pressure raising the psrts. Nothing changes, I still will go by the cap, although I think I was in the heavier oil brigade because of start up rattle.

This is bizarre reasoning. Where did you study physics and engineering?