BBQ tick - another attempt to understand

[TheLion]

Did they say what it's from? I've never seen fairy dust in my catch can - and others here on the forum report never seeing it. I'm really wondering if these guys you're talking to at Ford Performance always know what they are talking about - or are they just deflecting with canned answers to questions..

Some people don't notice it because of lighting and how much oil is in the cans. There's always been some in mine every time. According to FP it's wear metals from normal operation. On the corvett forums no one was able to get any analysis done, however a few guys had UOA's on cars with a lot of "fairy dust" or wear metals and showed very good UOA's despite. I suspect it could be a byproduct of the ZDDP tribo film as it breaks down along with other wear metals. It ends up in the catch can.

There are many sources of aluminum such as the pistons, rod bearings, block (aka cam shaft bearings) etc. I have not seen anyone try going to a thicker oil to see if it is reduced, but some cars seem to produce it constantly, here is the quite extensive dive into the "ferry dust" on the Z06 forum: https://www.corvetteforum.com/forum...ert-do-you-have-fairy-dust-in-your-oil-4.html

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[TheLion]

Bottom of page 2: 5W50 oil is required.
https://www.roushperformance.com/media/parts/manuals/422090-instructions.pdf

Also, look at page 73. 5W50 required for warranty. A "5W-50" sticker is put on the oil fill cap to warn someone not to put thinner oil in the engine.

I stand corrected on that one. Must not have shown up in the PDF search because it's an image, not text block. However their crate motors spec 5W-20, says right on their website. And Ford Performance also does not call for a viscosity change with their SC kit that I can find including in the pictures....I also downloaded the user manuals for the F-150's (regular, police and Raptor). None of them call for a viscosity changed except for 5W to 0W for cold climates. They still call for the same hot grade.

I don't think going from 5W-20 to 5W-30 is going to cause any issues and certainly it can compensate for heating, but I'm still quite skeptical that going from an engine built for 20 and 30 weight oils to a 50 weight would yield ideal results unless your subjecting it to extreme heat. Flow is based on pressure and resistance of the medium, the pump regulates a constant pressure, despite being positive displacement it bleeds off excess. 70 psi will achieve less flow for a 30 weight than a 20 weight.

There's no way you can achieve the same flow volume on the same clearances and the same pressure when the viscosity goes up. Viscosity is resistance to flow. Your violating basic physical principals. Pressure is potential energy to move a fluid from one location to another. Lower flow volume = longer dwell time = more localized heating of the oil. It works against the benefits of a higher viscosity. How much I don't know and as you stated, the benefits of the greater film strength may still be a net positive over the additional heating, but I don't now that for sure. I've only seen speculation from and here say but no actual data on this particular engine.

Don't assume that because one set engine behaved a certain way that the 5.0 will do likewise. Different engines can respond in surprisingly different ways. Does anyone have any data logs of track sessions on 20 and 30 weight? How about 50 weight? We maybe need to get some actual data to prove the ideal oil weight for the 5.0 under track conditions.

And, flow rates matter. You can only fill up the clearance until it is full. If the oil is fully filling the bearing clearance, then achieving higher flow rates are the only way to increase reliabiltiy. Increasing viscosity may not yield as much as you think. Say the bearing clerance hold 50 mL of fluid. 50 mL of 20 weight is the same as 50 mL of 30 weight. But 20 weight may out flow 30 weight. 20 weight will yield better cooling due to volume of flow. Thinner oils also are better thermal conductors.

And no, the S197's do NOT call for you to ever switch to 5W-50. The Track Pack S197's calls for 5W-50 all the time and it specs only full synthetics. The regular S197's call for 5W-20 all the time. No where in the manual does it ever say to change viscosity grade so anyone saying that is the case is incorrect.

Same thing with the Boss 302. It calls for 5W-50 all the time as does the GT350 with the Voodoo 5.2. So do FP's aluminator crate engines with forged pistons and rods. I expect they run larger clearances for reliability over efficiency in boosted or very high RPM applications. Allows more room for error and also distortion under load.

F-150's with the 5.0 call for 5W-20. All ecoboost are 5W-30 (might have slightly larger clearances for low rpm high torque use to allow more wiggle room for distortion). BTW Amsoil 0W-30 has a HTHS of 3.07 and is ACEA A5/B5. But their 5W-20 is not ACEA spec becuase HTHS is too low (minimum spec for ACEA A5/B5 is 2.9).

 

[accel]

Just for reference, since we are on the BBQ Tick thread I still have the following noises:

1. Occasional intermittent light knock when cold at idle, but can't hear it when starting from a stop or driving. Might do it when warm but I don't pay attention as much when warm and tend to focus more on the ticking.
2. A somewhat pronounced ticking (rythmic) when warm at idle.
3. 3000 RPM rattle when cold (I can hold in that RPM and vary throttle and make it louder or quieter), goes away after about the first minute or two of driving.

However TriboTEX did solve the BBQ Tick when starting from a stop. I have not been able to detect that noise since. I've also just recently changed the oil from Mobil 1 5W-20 to Ravenol SFE 5W-20 due to it's PAO baste stocks and extremely good (for a 20 weight) 2.9 HTHS for a little more added protection. So far I have stuck to 5k~6k OCI's but no Blackstone UOA's. I will do a UOA on Ravenol once it comes due probably mid summer 2019. Every single ticker I've seen that's still running has shown good UOA's despite the fact that they sound like something is legitimately wrong just for reference. It's not unique just to the 5.0 either. There are tons of Hemi's and even several LT1's that tick and run fine so it's far from a Ford only problem.

Oil pressure is normal and still in the range it has always been at. About 20 psi to 25 psi at idle fully warmed, varies a bit depending on outside temps and weather or not I just got done with a lot of high RPM WOT. Never goes below 70 psi when WOT during extended high RPM, typically when just normally driving and doing a quick WOT blip it's about 80 PSI, so there's no indication that the 3000 RPM rattle or the occasional intermittent knock at idle has anything to do with rod bearings. You spin a bearing and your oil pressure will go down. Ford performance noted that's how they keep track of rod bearing health in some of their track cars. They log oil pressure readings and establish a base line new. Once it starts to change significantly thats an indicator they are up for new bearings.

Fuel economy is stellar for this type of car with this gearing, I can still get up to 29~30 mpg on a known stretch of highway only previously was able to get 25~26 on before TriboTEX. Occasionally still get a burning oil smell after some hard driving, I do see some oil / grime accumulation around the dip stick tube, so maybe one of the bolts is a bit loose or a bad valve cover gasket. Had this issue since I first bought the car and it's dealership noted along with the 3000 rpm rattle.

Had a catalytic converter replaced around 23k miles under warranty. Bank 1. Threw a P0420 code and CEL illuminated like it should. No noticeable drive ability symptoms except some hickups in RPM dropping at idle more than normal prior to the dealer replacing it.

I also still get the "fairy dust" in my oil catch can every time I empty it after about 1,000 mile intervals just like on the Corvett forum I posted a link to a while back. I asked Ford Performance if they saw this and they said yes it's normal. Car is under a 100k/7yr ESP for power train, so if the engine eats itself, I got 4 years and 75,000 miles for that to occur before I'd be footing the bill thanks to Ford Performance warranty preserving power pack, which I've already had to use the warranty for to get the cat replaced (no issues, dealer treated it like a stock car since they did the install).

I'm running the following regarding engine related modifications:

1. Ford Performance Power Pack 2 installed at 17k. Car has NEVER had any other ECU calibration other than stock and Ford Performance, at least not since I've owned it.
2. Corsa Sport cat back exhaust that was on the car when I purchased it last December with 5,600 miles on the clock.
3. JLT 3.0 oil catch can.
4. TriboTEX Diesel concentration added at 21k.

Other than that the engine hasn't been touched. With my modifications I'd estimate I'm making around 465 to 475 hp at the crank. I only have run 93 pump gas since I've gotten it. BTW the rattle / knocking at 3000 RPM could be piston slap or it could be actual light pinging when the engine is open loop (mild pinging isn't harmful). I've never once heard detonation or "marbles" once warm under any condition, weather high RPM WOT or cruising at 75 on the highway, even going 35 down town in 5th gear a little under 1500 rpm.

Yup my engine is clanky, it literally sounds like a sowing machine. TriboTEX initially quieted it down, but after about 500 miles it actually made the noises more pronounced. Not louder but more distinct. I believe this is likely that once the ultra lubricious tribo film forms, parts are going to slide more easily and hence come to rest at a slightly higher velocity as there is less resistance to their motion. So valves are going to experience more of the springs energy (like using a slightly stronger spring), piston rings are going to slide more easily possibly allowing them to flop around a bit more etc.

That's where Archoil and CeraTec differ, they have additives that slightly alter the oils properties where TriboTEX does NOT interact with your oil at all. It has no chemical friction modifiers. It is only a DLC film and uses the oil as a carrier fluid like Archoil and CeraTec. Honestly, a car guy whose sensitive to noises and not familiar with the 5.0 and it's quirks would think something is seriously wrong with my engine. Oh and I burn only about 1/4 to 1/3 a quart of oil in the last 4,500 mile oil change when I initially added TriboTEX. Prior to that it was about 1/2 quart. So oil consumption did go down even further. And that's with lots of WOT high RPM driving on back roads. In both very cold and very hot conditions.

There's no reason for this engine to throw a rod bearing or have any major failures at this point given there's no CEL, no abnormal oil consumption, excellent fuel economy, awesome power / throttle response, perfectly smooth and consistent idle. But it sounds like it's dying sometimes...at least to me. My wife doesn't notice most of these nosies at all. So I'll continue this experiment in testing the reliability of Ford's 2nd generation 5.0L V8 when properly maintained. I'm also running the OE GT350 style paper conical air filter and will continue to use paper due to much better filtration than oiled or dry re-usable. I will also continue to use the OE FL-500S filter that meets USCAR36 requirements. Wear is directly related to particular size and concentration as well as the EP additive packages and bearing clearances. All play a role. Throw any one out of whack and you will have accelerated wear. TriboTEX should compensate should one get out of whack, but I'd rather not find out what the compensating limits are, so keep it clean and run it hard!

Just for ref reference- my cold engine start pressure is 90 psi. Hot engine idle about 18 psi. 5w20 mc.

 

[TheLion]

You asked for information on oil viscosity and cooling, here it is, this is my field of expertise (electrical engineering): https://electricenergyonline.com/en...mpact-of-oil-viscosity-on-the-performance.htm

I believe that the statements from Driven, Ford Performance and Engine Builder Mag regarding thinner oils providing better cooling is in regards to volume of flow. Using a thicker oil to compensate to excessive thermal loading is the only reason. A 20 F rise causes most 30 weights to become 20 weights. So it would indeed make sense to run 5W-30 for track or when highly modified if the car is often pushed, but not for street use unless your in a very hot climate like Austraila (hence why they spec 5W-30).

That would be the star example as we're not aware of any clearance differences for the Aussie cars and their manual actually changed the recommended viscosity grade mid year. 1st and 2nd rev called for 5W-20. But the 3rd revision called for 5W-30....it might even make sense to run 5W-20 in the winter and 5W-30 in the summer.

The 5.0's oil pump and clearances are designed for 5W-20 in the Mustangs and F-150's for their specified operating temperature ranges. But without added cooling, 5W-20 may not be optimal under track conditions as they might push the cooling system beyond the upper limits, so using a slightly higher viscosity 5W-30 may produce the same viscosity as 5W-20 under less stressful conditions or with added cooling. I think an air to oil cooler with 5W-20 would be just as good as 5W-30 with a stock cooling system.

Your basically using the inferior thermal transfer of 5W-30 (lower flow) under hotter than normal conditions to achieve 5W-20 viscosity. So everything will actually be operating at elevated temps, but your oil film thickness will still be in the ideal range. It's a compromise to better cooling.

But going with too high of a viscosity can cause localized over heating of the bearings due to inadequate flow volume and this could certainly cause oil starvation. There's a happy medium. How high is too high? I don't know. But there is NOT a single owners manual that calls for a car to switch from 5W-20 to 5W-50. The only one that calls for more than one viscosity is the 2018 GT's which call for 5W-20 for street and 5W-30 for track only. It's only one viscosity grade change. Some of the F-150's call for 0W-20 for very cold temps and 5W-20 for hotter temps...all the other user manuals call for only a single viscosity all the time with the 2018's being the exception of changing from a 20 to a 30 weight. The Camaro SS's also only call for a single grade change as do the Aussie 5.0's. So I'm at the point of 5W-30 as the heaviest I would go, but I think a SAE 0W-30 or an ACEA A5/B/5 5W-20 would be more optimal for hard street use. I'm running an ACEA 5W-20 with an HTHS of 2.9, but 8.4 at 100C. Very temp stable PAO blend.

1. S197 GT's 5W-20
2. S197 Track Pack GT's 5W-50
3. S197 Boss 302 5W-50
4. 2015-2017 Base, Premium and PP GT's 5W-20
5. GT350's 5W-50
6. 2018 Base, Premium and PP GT's 5W-20 for street and 5W-30 for track

I have a hard time seeing how following the OE oil spec on stock or Ford Performance tuned cars is going to lead to rod bearing failures. Can anyone point me to to a rash of 5W-20 related rod bearing failures? It certainly has almost no effect on the BBQ tick...but I do agree with GT Pony that going to a 5W-30 would provide more high temp protection when in hot environments or on track where there is excessive heat. But I believe it may be a bit too thick for street, short sprints at WOT the 5W-20 isn't going to heat up enough and will flow more, so under short intervals of WOT you may get more for 5W-20 than 5W-30. Track is sustained, street is not.

 

[TheLion]

Just for ref reference- my cold engine start pressure is 90 psi. Hot engine idle about 18 psi. 5w20 mc.

My idle pressure varies a little with oil brand. Thinner oils like PUP 5W-20 or M1 seem to be around 19~20 psi hot and around 70 to 80 psi hot in upper RPM ranges. My cold psi with MC is 90 to 100. I limit myself to a max of 4,000 rpm when cold, light throttle until it's warm. But I see 100 psi when cold with every oil (MC, PUP, M1 and Ravenol). All are 5W-20's in the 2000 to 4000 rpm range when very cold (as in 20-25F outside).

 

[accel]

My idle pressure varies a little with oil brand. Thinner oils like PUP 5W-20 or M1 seem to be around 19~20 psi hot and around 70 to 80 psi hot in upper RPM ranges. My cold psi with MC is 90 to 100. I limit myself to a max of 4,000 rpm when cold, light throttle until it's warm. But I see 100 psi when cold with every oil (MC, PUP, M1 and Ravenol). All are 5W-20's in the 2000 to 4000 rpm range when very cold (as in 20-25F outside).

My hot engine idle was taken with ac off by the way.

 

[TheLion]

I guess to summ it up, what I've really been trying to get at is that I do not believe running thicker oil is appropriate for street cars. I believe running 5W-30 is better suited to track work just like the 2018's manual calls for, but once you go back to street use to return to a good quality 5W-20.

For street cars I believe your best wear results will be achieved with a very temp stable 5W-20, just like the manuals call for. You need all three. Cold flow, good HTHS for hard sustained street use and ideal viscosity at 100C for optimal fuel economy and cooling.

You get nearly the HTHS protection of many SAE 5W-30's but better cold flow properties and 100C properties than 5W-30's by using an ACEA A5/B5 spec 5W-20. Maybe a SAE 0W-30 might be a good in between for hard street as it has better cold flow properties than a SAE 5W-30 but with similar higher temp protection of a thin 5W-30 / thick 5W-20.

In that regard AMSOIL 0W-30 looks like a good in between for hard street use / hot climates or even track use but I don't think you can go wrong with a 5W-20 that has a HTHS of 2.9 to 3.0 like Ravenol or RedLine nor do I think there's enough of a difference in HTHS between those and AMSOIL's 0W-30 and 5W-30 offerings to really justify running a 30 weight in an engine designed for 20 weight other than track due to abnormally high thermal loads. You have to balance cam / timing chain wear during cold starts / normal use with high rpm bearing protection. That means street oils are actually harder to formulate than race oils ironically, especially with limits on EP additives and such a broad operating temp range. Race oils focus on high temp and have no additive limits.

HTHS comparrison (Track, WOT, High RPM:

Ravenol SFE 5W-20 vs. AMSOIL SS 5W-30: (1-(2.9/3.11))*100 = 6.8% difference...
Ravenol SFE 5W-20 vs. AMSOIL SS 0W-30: (1-(2.9/3.07))*100 = 5.5% difference...
Ravenol SFE 5W-20 vs. RedLine 5W-20: (1-(2.9/3.07))*100 = 3.3% difference...

Viscosity at 100C Comparison (Normal Use):

But now look at the viscosity at 100C:

Ravenol SFE 5W-20 vs. AMSOIL SS 5W-30: (1-(8.4/10.4))*100 = 18.4% difference...
Ravenol SFE 5W-20 vs. AMSOIL SS 0W-30: (1-(8.4/3.07))*100 = 19.2% difference...
Ravenol SFE 5W-20 vs. RedLine 5W-20: (1-(8.4/9.0))*100 = 6.7% difference...

And viscosity at 40C (cold start / cold driving conditions):

Ravenol SFE 5W-20 vs. AMSOIL SS 5W-30: (1-(8.4/10.4))*100 = 24.1% difference...
Ravenol SFE 5W-20 vs. AMSOIL SS 0W-30: (1-(8.4/3.07))*100 = 20.7% difference...
Ravenol SFE 5W-20 vs. RedLine 5W-20: (1-(8.4/9.0))*100 = 14.5% difference...

We are forgetting that volume of flow affects boundary layer lubricated parts as well like cams, valve guides, timing chains, piston rings etc. Many of these parts only operate in Hydrodynamic regime at higher RPM's, but not at lower RPM's where street cars spend a lot of time.

The oil carries the EP additives, without the oil carrying enough ZDDP or MoDTC, you don't have enough additives being supplied and boundary lubrication parts wear faster / see higher friction. Volume of flow matters just as much as film strength. It's the other side of the coin and 5W-20's are more ideal in those terms when the pump is designed around optimal flow of 20 weights. Pressure is regulated to specific points because it's assumed your running a particular viscosity of oil that will have a specific volume of flow.

Film thickness has no discernible effect on boundary layer lubrication...but EP additives do and supplying enough EP lubricants is equally important. Again, the exception is track and high ambients where your exceeding the design range. I Still disagree that 5W-30's are optimal for street use. And for track use we care about protection as much as making power. Controlling temperature and using a more temperature stable base oil is a better solution to just relying on over heating a thicker oil, but I understand some times it's not entirely practical to use better cooling (cost or complexity etc.).

Can't get around that pesky resistance to flow however...thicker oils simply flow less volume under the same pressure. Pressure is potential energy. Flow is energy in motion or work being done. What about cooling? The oil squirters are going to achieve higher volume of flow with thinner oils as well = more cooling of the pistons. As the oils thin out even more, their volume of flow increases further as long as the oil pump can regulate the set pressure.

 

[TheLion]

Take ways: http://kingbearings.com/wp-content/uploads/2014/10/optimization-of-clearance-engine-professional.pdf

1. Pmax/Pav between 30 and 60 weight oils is only 2 with a 0.002" clearance despite being double the viscosity. The Smaller the clearances the more uniform the oil film distribution with ALL viscosity. The differences between 20 and 30 weight oils are extremely small.

2. Added cooling can compensate for increased thermal stresses. 5W-20 at 190F will result in the same film thickness at 5W-30 at 210F (assuming both are regulated to the same pressure). So 5W-20 with added cooling will achieve the same protection as 5W-30 with less cooling. The optimal oil viscosity and clearances are entirely dependent on TEMPERATURE. A 5W-30 and a 0.002" clearance may be optimal at one temperature but not at another. Without knowing the temperature ranges and the actual clearances we cannot know the optimal viscosity....

3. More stable base oil blends can also compensate for increased thermal stresses. Many ACEA A5/B5 5W-20 oils produce nearly the same HTHS viscosity as thinner SAE 0W/5W-30's but have thinner viscosity at 100C and 40C where most daily use occurs. The differences in HTHS are only typically 3%-6% between them and are negligible. The takeaway is that PAO and Ester base oils provide the greatest temperature stability regardless of the blended viscosity and are the best choice for high RPM protection of the rod bearings and main bearings.

3. At low oil clearance (tight clearance) the journal rotation causes considerable heating of high viscosity index oils. Therefore their viscosity drops getting close viscosity of the oil with low viscosity index. As a result the power loss at low oil clearance is relatively low for all grades of lubricants: http://www.substech.com/dokuwiki/do...y_on_hydrodynamic_friction_of_engine_bearings

4.

For the oil 10W30 the greatest value of oil film thickness is achieved at clearance of 0.002” (1/1000 of the bearing diameter).

. This is only relevant at the 175F oil inlet temperature their oil was tested at. A 20F drop or rise in average temperature would invalidate this as the ideal weight for that clearance. Change the clearances and again this changes. It's all about ratios and temperature stability. Thicker oils do NOT inherently provide more meaningful protection. The best protection is achieved by using the most optimal viscosity for the clearances and temperatures. But yes, using one grade thicker can provide more optimal protection for track use where average temperatures are higher, but is not ideal for street cars that only see those conditions for short time periods (drag racing falls under street due to the very short thermal loading periods).

5. Tighter clearances reduce oil leakage which helps maintain oil pressure and prevent oil starvation. However it also increases temperature rise. There is a significant temperature rise, especially at high RPM, when using clearances much smaller than 0.0020".

6. At higher RPM and higher loading pressure, a smaller clearance is generally optimal as long as the bearing has a high eccentricity.

Some more food for thought: rod bearing clearance specifications for the Boss 302: 0.0020" to 0.0025"
Source: https://performanceparts.ford.com/download/instructionsheets/FORDINSTSHTM-6009-363.PDF

Runs MC 5W-50 that typically shears down quickly to about 30 weight and is the spec oil for that engine. Looks about right to me. Remember, we must consider HTHS when looking at clearances and the King Bearings article does not dive into HTHS specs of their test oils. So we can only assume their oils are typical SAE grades with typical HTHS numbers. The most optimal viscosity becomes more complicated due to shear, variations among even the same oil weight and variations in temperature stability.

But I think we can draw a conclusion as to the most ideal protection: ACEA A5/B5 5W-20 weight oils have nearly identical HTHS characteristics to many of the thinner SAE 5W-30's that are off the shelf. SAE 5W-30's are what King Bearings used in testing. So under HTHS conditions, ACEA A5/B5 20 weights are equivalent to a SE 30 weight by SAE requirements, but still act like typical SAE 5W-20's at lower temps. The best of both worlds and it appears that temperature stability of the base oil is very important in high RPM protection. For a street car, you need BOTH low temperature performance AND high temperature performance because the car sees both types of conditions. Nothing is better suited than ACEA A5/B5 spec 5W-20 PAO or Ester based oils.

At some point the differences between 20 and 30 weights become meaninglessly small, the closer the grades and the tighter the clearances, the more irrelevant the differences. So, other than cost, why run a cheap 5W-30 when you have several very good 5W-20's with premium EP anti-wear packages and provide equivalent HTHS protection of a SAE 5W-30 that also provide you with more ideal street / every day driving anti-wear protection? If you need more protection, you need more cooling. Combining both is the best solution bar none (by that I mean regulated cooling to avoid over cooling during normal operation).

A thermostatic air to oil cooler like Mishimoto's should work quite well for track duty when combined with an ACEA A5/B5 spec 5W-20 oil like Ravenol, RedLine or Driven.

 

[GT Pony]

You asked for information on oil viscosity and cooling, here it is, this is my field of expertise (electrical engineering): https://electricenergyonline.com/en...mpact-of-oil-viscosity-on-the-performance.htm

I believe that the statements from Driven, Ford Performance and Engine Builder Mag regarding thinner oils providing better cooling is in regards to volume of flow.

Yes, I agree to some degree. The other aspect is that thinner oils have less shearing in bearings because the MOFT is smaller. Your link about thermal article about transformer cooling (even though not a direct analogy) even says it's the flow rate of the oil that's the big factor. Quote: "Or in words: The lower the viscosity, the higher the circulation speed of the oil which equates in a higher quantity of heat being dissipated."

The thermal conductivity between different motor oil viscosity is most likely in the noise level and doesn't make much difference. It's the flow rate of the oil that makes the difference in terms of absorbing and carrying away heat.

But, keep in mind that with a positive displacement oil pump the flow rate is going to basically remain the same as long as the oil pump is not in pressure relief. PD oil pumps really don't go into pressure relief even with thicker oils when at full operating temperature. Of course, almost any viscosity of oil is going to make a PD oil pump hit pressure relief on a cold start if the engine is revved up pretty good. This is a good reason to never beat on an engine until the oil is close to or at full operating temperature.

So the bottom line is that even 5W-50 at full operating temperature probably isn't going to make the PD oil pump hit pressure relief, and therefore there really isn't any loss of flow due to the pressure aspect. The bearing does however flow less due to it's hydrodynamic flow from rotation, and that along with higher MOFT and more shearing heat is why thicker oils heat up more inside journal bearings as they rotate. But, again the bottom line with all that considered is that thicker oils always result in more MOFT which is the main mode of preventing metal-to-metal contact between parts.

Using a thicker oil to compensate to excessive thermal loading is the only reason. A 20 F rise causes most 30 weights to become 20 weights. So it would indeed make sense to run 5W-30 for track or when highly modified if the car is often pushed, but not for street use unless your in a very hot climate like Austraila (hence why they spec 5W-30).

Gets just as hot in many parts of the USA as it does in Australia, but there is no CAFE in Australia. Ford wouldn't recommend using 5W-30 all year round in Australia if there was any issue with using it in the Coyote. During the winter time, temps can get down near freezing in parts of Australia.

1. S197 GT's 5W-20
2. S197 Track Pack GT's 5W-50
3. S197 Boss 302 5W-50
4. 2015-2017 Base, Premium and PP GT's 5W-20
5. GT350's 5W-50
6. 2018 Base, Premium and PP GT's 5W-20 for street and 5W-30 for track

So an interesting exercise would be to find the official bearing clearance specs from Ford and compare them all. My bet is they will all be very similar. I highly doubt Ford increased the bearing clearance on the cars listed there that Ford specified 5W-50 for. Roush wouldn't require 5W-50 in a regular Coyote GT after installing a supercharger if the bearings were "too tight" for 5W-50.

 

[GT Pony]

Can't get around that pesky resistance to flow however...thicker oils simply flow less volume under the same pressure. Pressure is potential energy. Flow is energy in motion or work being done. What about cooling? The oil squirters are going to achieve higher volume of flow with thinner oils as well = more cooling of the pistons. As the oils thin out even more, their volume of flow increases further as long as the oil pump can regulate the set pressure.

What you're missing is that positive displacement oil pumps will give the SAME flow by increasing the pressure - the pressure increases when a thicker oil is used because the PD is forcing the SAME volume through the fixed resistance of the oiling system. Your own oil pressure observations with different oils has shown you that on the oil pressure gauge. The only time you start losing oil flow is when the PD oil pump goes into pressure relief and starts shunting some of it's output flow back to the pump inlet.

As mentioned earlier, when the oil is at full operating temperature (even 5W-50), it's too thin to make the oil pump hit pressure relief, even at redline. The PD oil pump's relief valve is set to ensure that high engine RPM with very cold thick oil (even 5W-20 is very "thick" when cold) doesn't over pressurize the system and cause physical damage.

 

[GT Pony]

At some point the differences between 20 and 30 weights become meaninglessly small, the closer the grades and the tighter the clearances, the more irrelevant the differences. So, other than cost, why run a cheap 5W-30 when you have several very good 5W-20's with premium EP anti-wear packages and provide equivalent HTHS protection of a SAE 5W-30 that also provide you with more ideal street / every day driving anti-wear protection?

I'll be running 5W-30 all the time from here on out, and sleep well at night. All my oil research landed me to go with Valvoline Advanced full synthetic because of its dexos1 Gen2 SN+, has 3.2 HTHS and 9% Noack. It's KV100 is also at the 10.2 cSt "sweet spot". And it's only $22 for a 5 quart jug at Walmart and is easily available. No need for expensive "boutique" oils for my GT.

 

[Condor1970]

Good Heavens. I'm an.engineer too, and read through a lot of this back and forth. I'm about to just go with QSUD 5w30 cuz it's cheap, and just toss in a dab of Ceratech, but only if it needs it.

This is exhausting. You boys are beatin' this dead horse into the ground.

 

[GT Pony]

Good Heavens. I'm an.engineer too, and read through a lot of this back and forth. I'm about to just go with QSUD 5w30 cuz it's cheap, and just toss in a dab of Ceratech, but only if it needs it.

This is exhausting. You boys are beatin' this dead horse into the ground.

Post No. 582 sums it up for me. Having 5W-30 in the sump makes me feel better knowing what I know about journal bearings and how viscosity affects them. Not to mention Ford recommends it in Coyotes in countries not under CAFE type rules.

 

[benjaminforeal]

I'm also an engineer, which is why I'm having Ford buying this ticking pony back.

 

[accel]

I'm also an engineer, which is why I'm having Ford buying this ticking pony back.

I (being an engineer as well) agree with you.

- there's no explanation from ford on what it is and why this is normal.
- tick under warranty may develop into serious engine problem out of warranty.
- this diminishes resale value dramatically as no one will want to buy ticking/knocking car.
- so if you can make ford buy it that's an option.

I like the car very much and will pursue warranty repair until under warranty or until fixed.

If there was any other car at market that would look as attractive to me as a gt (price/features/looks/legacy/potential/.../.../...), I'd probably play lemon bay back way of getting out of it. But there isn't.

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