BBQ tick - another attempt to understand

[Condor1970]

I've been doing doing some reading on oil cavitation in bearings, and their affects. It seems that in older diesel engines that used to have Lead-Antimony (Babbit) bearing surfaces were quite susceptible to erosive damage from this cavitation. However, modern Tin-Aluminum bearings show very little if any issue with mild oil cavitation in higher compression engines. This is sort of a testament to what GT Pony had posted a while back about damage from oil cavitation. I think this kind of goes back to why all of a sudden in the newer 2018+ engines running 12:1 compression ratio tends to have a higher occurrence of this ticking noise. The force being to applied to the journals with a higher compression ratio, also has a much higher detention force on the journals from the DI system. From what I understand, this tick tends to go away in most cases when the ignition coil for Cylinder-3 is unplugged while the engine in running. This would indicate to me that for whatever reason, the location of that particular cylinder in this V8 5.0L design, tends to have a situation that creates audible oil cavitation in this higher compression setup.
If I find the diagrams again I'll post them. But they showed how older engines running softer bearing materials suffered damage over time using older Babbit type bearings. Where the same diesel engine running a newer set of Tin-Aluminum bearings with a much harder alloy, had no such indications of wear or damage over the same amount of time of operation, even though oil cavitation was still present. Interesting.

As a result, my assumption is that because Fords Coyote uses more modern/hard bearing alloys, this ticking is not really an issue. Even when engines are torn apart with bearings inspected/measured and appear to be perfectly fine.

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[NastyPumpkin]

I've been doing doing some reading on oil cavitation in bearings, and their affects. It seems that in older diesel engines that used to have Lead-Antimony (Babbit) bearing surfaces were quite susceptible to erosive damage from this cavitation. However, modern Tin-Aluminum bearings show very little if any issue with mild oil cavitation in higher compression engines. This is sort of a testament to what GT Pony had posted a while back about damage from oil cavitation. I think this kind of goes back to why all of a sudden in the newer 2018+ engines running 12:1 compression ratio tends to have a higher occurrence of this ticking noise. The force being to applied to the journals with a higher compression ratio, also has a much higher detention force on the journals from the DI system. From what I understand, this tick tends to go away in most cases when the ignition coil for Cylinder-3 is unplugged while the engine in running. This would indicate to me that for whatever reason, the location of that particular cylinder in this V8 5.0L design, tends to have a situation that creates audible oil cavitation in this higher compression setup.
If I find the diagrams again I'll post them. But they showed how older engines running softer bearing materials suffered damage over time using older Babbit type bearings. Where the same diesel engine running a newer set of Tin-Aluminum bearings with a much harder alloy, had no such indications of wear or damage over the same amount of time of operation, even though oil cavitation was still present. Interesting.

As a result, my assumption is that because Fords Coyote uses more modern/hard bearing alloys, this ticking is not really an issue. Even when engines are torn apart with bearings inspected/measured and appear to be perfectly fine.

Yes, this is what the S550 Powertrain engineers have told me almost two years ago.

 

[GT Pony]

It very well could be oil cavitation, but if so then why do only some of the Coyotes tick? Even if it's oil cavitation, there must be something like differences in parts clearances that makes some tick and others not tick. And from what I've researched, it just seems very strange that journal bearings would start cavitating and ticking right after an oil change, or almost instantly go quiet if an anti-friction additive like Ceratec was added to the oil. I don't think cavitation of oil in journal bearings is that sensitive to the oil formulation from the research papers I've read about bearing cavitation.

 

[kluke15]

It very well could be oil cavitation, but if so then why do only some of the Coyotes tick? Even if it's oil cavitation, there must be something like differences in parts clearances that makes some tick and others not tick. And from what I've researched, it just seems very strange that journal bearings would start cavitating and ticking right after an oil change, or almost instantly go quiet if an anti-friction additive like Ceratec was added to the oil. I don't think cavitation of oil in journal bearings is that sensitive to the oil formulation from the research papers I've read about bearing cavitation.

the difference in clearances from one vehicle to another i believe would account for why some do and others dont and why some people get relief with thinner oil and others with thicker oil. this is keeping in mind fords quality control ability that weve seen from panel gaps and all the other stuff.

 

[Condor1970]

It very well could be oil cavitation, but if so then why do only some of the Coyotes tick? Even if it's oil cavitation, there must be something like differences in parts clearances that makes some tick and others not tick. And from what I've researched, it just seems very strange that journal bearings would start cavitating and ticking right after an oil change, or almost instantly go quiet if an anti-friction additive like Ceratec was added to the oil. I don't think cavitation of oil in journal bearings is that sensitive to the oil formulation from the research papers I've read about bearing cavitation.

Well, let's assume that the tick forms as the engine breaks in. The first few thousand miles of break in, does in fact cause some minute changes in clearances. Hence the term "break-in".

I "suppose" it's possible that just minute changes could cause things to progress and get more audible with some engines, even when measurements are taken on bearings and they're still in spec. Most suddenly noticeable when oil is changed. I think that Ceratec works for 2 reasons. First, it makes the oil so slick it flows better through the bearing. Second, the flash point slightly changes when a solid particulate is added. Same principle as when the new oil ticks, but slowly goes away as carbon builds up over time.
This whole theory also falls in line with my thoughts on how the tick really seems to be pressure related. As engine RPM increases, the tick goes away when it's up around 30psi. This is because the pump is creating enough pressure to prevent flashing due to a low pressure area forming as the crank rotates.
Honestly, if we could all figure out a way to keep the solenoid bypass shut, or at least figure out how to keep idle pressure above 25psi, then none of us would ever hear the tick again. Best explanation I can muster up.

Then, we can spend the other 50% of our time arguing about the cause of the 2k Rattle.

 

[GT Pony]

Well, let's assume that the tick forms as the engine breaks in. The first few thousand miles of break in, does in fact cause some minute changes in clearances. Hence the term "break-in".

I "suppose" it's possible that just minute changes could cause things to progress and get more audible with some engines, even when measurements are taken on bearings and they're still in spec. Most suddenly noticeable when oil is changed. I think that Ceratec works for 2 reasons. First, it makes the oil so slick it flows better through the bearing. Second, the flash point slightly changes when a solid particulate is added. Same principle as when the new oil ticks, but slowly goes away as carbon builds up over time.
This whole theory also falls in line with my thoughts on how the tick really seems to be pressure related. As engine RPM increases, the tick goes away when it's up around 30psi. This is because the pump is creating enough pressure to prevent flashing due to a low pressure area forming as the crank rotates.
Honestly, if we could all figure out a way to keep the solenoid bypass shut, or at least figure out how to keep idle pressure above 25psi, then none of us would ever hear the tick again. Best explanation I can muster up.

Then, we can spend the other 50% of our time arguing about the cause of the 2k Rattle.

I've posted this link to a PDF paper before that was a study of oil cavitation in journal bearings (posted again below). It even has photos through a clear journal bearing showing the "oil wedge" (of air) that is created inside a journal bearing as it rotates. The larger the oil wedge, the more likely there might be cavitation.

Of all the reading I've done on journal bearings and oil cavitation, I've never came across anything about how the "flash point" or "cavitation sensitivity" of oil could change due to slight changes in the oil composition. If you have some technical links that would be great, because I'm wondering where you're coming up with the part in red above.

Also, the oil flow through a journal bearing is a direct function of the bearing physical design, the oil viscosity, engine RPM and oil supply pressure at the inlet of the bearing. I agree that oil pressure at idle is the lowest it's going to be - especially on the 3rd Gen Coyote with the ECU controlled oil pump - and the paper I linked does say that oil cavitation is a function of oil pressure to the bearing, so at least that correlates. But in the Conclusions (section 5), it also says that the oil wedge increases (which means more likely to cavitate) when the bearing speed increases, and the oil viscosity increases. These two characteristics are opposite of the BBQ tick because it only starts after the oil is hot and thinned down and at low speeds (idle to 1500 RPM) - per the Ford SSM on the BBQ/typewriter tick. Per the linked paper, the cavitation would be much more pronounced or likely with cold oil and at higher engine RPM. This is why I keep thinking it's something else besides oil cavitation, and something related to parts clearances and the effect of the oil friction level.

http://ir.nsfc.gov.cn/paperDownload/1000013598568.pdf

 

[Condor1970]

I've posted this link to a PDF paper before that was a study of oil cavitation in journal bearings (posted again below). It even has photos through a clear journal bearing showing the "oil wedge" (of air) that is created inside a journal bearing as it rotates. The larger the oil wedge, the more likely there might be cavitation.

Of all the reading I've done on journal bearings and oil cavitation, I've never came across anything about how the "flash point" or "cavitation sensitivity" of oil could change due to slight changes in the oil composition. If you have some technical links that would be great, because I'm wondering where you're coming up with the part in red above.

Also, the oil flow through a journal bearing is a direct function of the bearing physical design, the oil viscosity, engine RPM and oil supply pressure at the inlet of the bearing. I agree that oil pressure at idle is the lowest it's going to be - especially on the 3rd Gen Coyote with the ECU controlled oil pump - and the paper I linked does say that oil cavitation is a function of oil pressure to the bearing, so at least that correlates. But in the Conclusions (section 5), it also says that the oil wedge increases (which means more likely to cavitate) when the bearing speed increases, and the oil viscosity increases. These two characteristics are opposite of the BBQ tick because it only starts after the oil is hot and thinned down and at low speeds (idle to 1500 RPM) - per the Ford SSM on the BBQ/typewriter tick. Per the linked paper, the cavitation would be much more pronounced or likely with cold oil and at higher engine RPM. This is why I keep thinking it's something else besides oil cavitation, and something related to parts clearances and the effect of the oil friction level.

http://ir.nsfc.gov.cn/paperDownload/1000013598568.pdf

The oil flashed easier because it IS hot, and closer to its flashpoint. So, you're saying Ford and Chevy are both wrong? Especially since that's the conclusion they came to in their testing of diesel and Fords high compression gasoline engines? And no, you need to get over the "big end" clearance theory. That's been dis-proven by two people on this forum and YouTube, both. Even when a dealer told one guy it was big ends, he had them measured by an independent mechanic, and they were all in spec. So, the dealer was wrong.

And yes, the flashpoint and even boiling point of many liquids will change as you add other compounds. Especially solid particulates that impart into the liquid on a molecular level. It's not much unlike water. Water boils at 212F no matter what. But, you add a teaspoon of sugar, and it's still mostly water, yet it's boiling point increases quite notably for the making of candy. That's just one obvious example of how a liquid will change it's flashpoint when particulates are added. I know I've mentioned this in the past.

Heck, all this may be moot, because to me it still sounds a lot like HLA's that aren't fully inflated at low rpm/oil pressure.

Although, I will say even the Toyota Tacoma, one of the most reliable trucks and 3.5L engines on the road has the exact same Typewriter Tick. Except they call it the Taco-Tick.

Notice how the tick became much more prominent when rpm and oil pressure dropped.



Toyota has also come out said the noise is normal. Apparently, they say it's "self cleaning DI injectors"??? Not sure how Ceratec would affect that in the Coyote though.

 

[GT Pony]

The oil flashed easier because it IS hot, and closer to its flashpoint. So, you're saying Ford and Chevy are both wrong? Especially since that's the conclusion they came to in their testing of diesel and Fords high compression gasoline engines? And no, you need to get over the "big end" clearance theory. That's been dis-proven by two people on this forum and YouTube, both. Even when a dealer told one guy it was big ends, he had them measured by an independent mechanic, and they were all in spec. So, the dealer was wrong.

And yes, the flashpoint and even boiling point of many liquids will change as you add other compounds. Especially solid particulates that impart into the liquid on a molecular level. It's not much unlike water. Water boils at 212F no matter what. But, you add a teaspoon of sugar, and it's still mostly water, yet it's boiling point increases quite notably for the making of candy. That's just one obvious example of how a liquid will change it's flashpoint when particulates are added. I know I've mentioned this in the past.

Not sure what you mean by "flashing" ... it certainly can't be what's commonly refereed to flashpoint, because most automotive or diesel engine oil will have a flashpoint around the 425 to 460° F range. No way any oil inside a journal bearing while idling at 800 RPM is at that temperature. If the ticking was caused by oil flashing when it exits the journal bearings, every car on the road would be ticking. So again, why would oil "flashing" only be specific to just a handful of engines.

https://mrtlaboratories.com/preventative-maintenance-flash-point-of-lubricating-oil/

I've don't recall seeing the official report from this "independent mechanic", so if you have a link please post it up, I'd like to read what he said. Measuring big end rod side clearance isn't rocket science, so I can't see how the Ford shop could be that far off from what the actual side clearances where.

I'll never "get over" the big end clearance theory. Just because they were still "in spec" doesn't mean they can't still slide around side-to-side for some reason and make ticking noises when they collide with each other or with the side of the crankshaft journal shoulder. And besides, just because a guy found his to be within spec doesn't mean others might not be at the extreme limit of the spec or even out of spec.

Adding an anti-friction additive like Ceratec could certainly effect how the rod big ends behave side-to-side on the journals, and that makes more sense then oil cavitation or "flashing" from everything I've researched. Besides, why was Ford replacing engines/short blocks like mad when someone came in with the BBQ tick, then stopped the warranty bleeding when they came out with the typewriter tick SSM. Ford wasn't replacing engines/short blocks without even tearing down an engine to inspect it for the noise source because they knew it was normal oil cavitation.

 

[Condor1970]

Not sure what you mean by "flashing" ... it certainly can't be what's commonly refereed to flashpoint, because most automotive or diesel engine oil will have a flashpoint around the 425 to 460° F range. No way any oil inside a journal bearing while idling at 800 RPM is at that temperature. If the ticking was caused by oil flashing when it exits the journal bearings, every car on the road would be ticking. So again, why would oil "flashing" only be specific to just a handful of engines.

https://mrtlaboratories.com/preventative-maintenance-flash-point-of-lubricating-oil/

I've don't recall seeing the official report from this "independent mechanic", so if you have a link please post it up, I'd like to read what he said. Measuring big end rod side clearance isn't rocket science, so I can't see how the Ford shop could be that far off from what the actual side clearances where.

I'll never "get over" the big end clearance theory. Just because they were still "in spec" doesn't mean they can't still slide around side-to-side for some reason and make ticking noises when they collide with each other or with the side of the crankshaft journal shoulder. And besides, just because a guy found his to be within spec doesn't mean others might not be at the extreme limit of the spec or even out of spec.

Adding an anti-friction additive like Ceratec could certainly effect how the rod big ends behave side-to-side on the journals, and that makes more sense then oil cavitation or "flashing" from everything I've researched. Besides, why was Ford replacing engines/short blocks like mad when someone came in with the BBQ tick, then stopped the warranty bleeding when they came out with the typewriter tick SSM. Ford wasn't replacing engines/short blocks without even tearing down an engine to inspect it for the noise source because they knew it was normal oil cavitation.

Sorry, I meant essentially "boiling", "vaporizing", etc. Not flashing by igniting. My poor choice of words.

And yes, Ford was replacing engines without even knowing exactly what the problem is. Ford does not do the diagnosis, the dealers do. They come up with a so called reason, then put in a request. Ford started replacing engines until they realized what it actually was, after getting the engines back and testing them in their plant to see exactly what was wrong with them. Then put a stop to it with an SSM.

It's a safe bet that the majority of the engines replaced because of the tick had nothing wrong with them. Including the ones with supposed cylinder scuffing, which the pics I saw looked like normal wear for hard run engines that frequent the drag strip.

 

[GT Pony]

Sorry, I meant essentially "boiling", "vaporizing", etc. Not flashing by igniting. My poor choice of words.

Oil is far from flashing or boiling when going through journal bearings. And like said before, if oil did "flash" or "boil" when going through a journal bearing at 800 RPM, them there would be many more cars on the road ticking besides some of the Mustang and a couple others.

http://www.petroleum.co.uk/oil-as-a-lubricant

"Lubricating oils, as it turns out, have an average chain length of 36 carbon atoms, this gives them a very high boiling point (somewhere around 300 degrees Celsius or 572 degrees Fahrenheit)."

And yes, Ford was replacing engines without even knowing exactly what the problem is. Ford does not do the diagnosis, the dealers do. They come up with a so called reason, then put in a request. Ford started replacing engines until they realized what it actually was, after getting the engines back and testing them in their plant to see exactly what was wrong with them. Then put a stop to it with an SSM.

It's a safe bet that the majority of the engines replaced because of the tick had nothing wrong with them. Including the ones with supposed cylinder scuffing, which the pics I saw looked like normal wear for hard run engines that frequent the drag strip.

If Ford thinks it's actually oil cavitation that is "normal" and doesn't cause any long term damage, etc ... then why didn't they just come out and say so in the typewriter tick SSM? Many pieces of this puzzle just don't fit together IMO ... never have.

It's OK to agree to disagree ...

 

[GT Pony]

Some good journal bearing reading for those interested:
https://docplayer.net/3306728-Bearings-and-bearing-metals.html

Note that as journal bearing clearance increases, the chances of oil cavitation increases. Excessive bearing clearance can also result in other kinds of noises at certain RPM and engine loads.

If it's oil cavitation, then perhaps some guys have rod and/or crank bearings that have too much clearance. I don't recall anyone actually measuring every journal bearing clearance on their Coyote. I asked many times to guys who had the dealer tear down a Coyote if the mechanic actually did bottom end measurements (bearing clearances and rod side clearance), but seems nobody could come up with some actual numbers measured.

 

[Condor1970]

Some good journal bearing reading for those interested:
https://docplayer.net/3306728-Bearings-and-bearing-metals.html

Note that as journal bearing clearance increases, the chances of oil cavitation increases. Excessive bearing clearance can also result in other kinds of noises at certain RPM and engine loads.

If it's oil cavitation, then perhaps some guys have rod and/or crank bearings that have too much clearance. I don't recall anyone actually measuring every journal bearing clearance on their Coyote. I asked many times to guys who had the dealer tear down a Coyote if the mechanic actually did bottom end measurements (bearing clearances and rod side clearance), but seems nobody could come up with some actual numbers measured.

It says too high a clearance. But, none of these engines have too high a clearance. And it's not just with this engine. A 0.5mm clearance between big ends is common , including the LS I believe. In fact, some of the old big blocks were even higher. I can see how it might be a problem if the clearance was way out of tolerance, but not while it's still in tolerance in accordance with design spec. Besides, cavitation erosion apparently is not an issue with the newer harder Tin-Aluminum alloy bearings. Also, the rod ends themselves are steel, so no issue there either. It may in fact be oil cavitating, or bubbles flashing as it exits the big end, but not because the big ends are out of tolerance. It's primarily because of the new engines running higher compression with lower oil pressures in the bearings at low rpm.

 

[GT Pony]

It says too high a clearance. But, none of these engines have too high a clearance. And it's not just with this engine. A 0.5mm clearance between big ends is common , including the LS I believe. In fact, some of the old big blocks were even higher. I can see how it might be a problem if the clearance was way out of tolerance, but not while it's still in tolerance in accordance with design spec.

The paper was talking about journal bearing clearance ... not rod big end side clearance.

I don't recall anybody here ever reporting what the actual rod and crankshaft bearing clearances where measured out to be (using Plastigage or other means) on a ticking engine.

The point was that excessive journal bearing clearance can contribute to oil cavitation. It can also cause the bottom end to make other noises beside a ticking at idle if the engine load and RPM are just right. I'm sure you've heard some Coyote videos where the engine sounds horrible as it's revved up in neutral to around 1500~1700 RPM, which is typically a sign of loose rod bearings. This might also explain why some Coyotes tick louder and sound much worse than others.

 

[Condor1970]

The paper was talking about journal bearing clearance ... not rod big end side clearance.

I don't recall anybody here ever reporting what the actual rod and crankshaft bearing clearances where measured out to be (using Plastigage or other means) on a ticking engine.

The point was that excessive journal bearing clearance can contribute to oil cavitation. It can also cause the bottom end to make other noises beside a ticking at idle if the engine load and RPM are just right. I'm sure you've heard some Coyote videos where the engine sounds horrible as it's revved up in neutral to around 1500~1700 RPM, which is typically a sign of loose rod bearings. This might also explain why some Coyotes tick louder and sound much worse than others.

The problem, is that the sound goes away once oil pressure is back up to normal around 30psi. This is where most engines ran at idle just a few years ago. Now, they are running them at much lower oil pressures at idle. So, if you have bearings that are perfectly fine, you may still hear some ticking. Not because of the bearings being bad, but because of oil pressure. There's also a theory that if you have VERY tight bearings, then when the oil ejects from the bearing, that oil flashes to vapor in a cavitating manner with the same noise.

You have to remember, Ford gets all these engines back, and they tear them down and measure everything. If there was a bearing problem, it would have come out in that SSM that bearings are bad...not that the noise is normal. It's quite possible that as these bearings break in, they do open up a little, as is normal. But, some tend to start ticking. And, it's usually around cylinder #3. This is why engines even in the 2019's and now 2020's still tick just like the rest. They would have resolved the issue by 2019 if there really was a bearing problem in this new engine.

 

[GT Pony]

The problem, is that the sound goes away once oil pressure is back up to normal around 30psi. This is where most engines ran at idle just a few years ago. Now, they are running them at much lower oil pressures at idle. So, if you have bearings that are perfectly fine, you may still hear some ticking. Not because of the bearings being bad, but because of oil pressure. There's also a theory that if you have VERY tight bearings, then when the oil ejects from the bearing, that oil flashes to vapor in a cavitating manner with the same noise.

I highly doubt there is any oil "flashing" or "boiling/vaporization" going on as the oil comes out of the bearing since going through the bearing would have to raise the oil temperature from ~200F to over 450F. If you study up on journal bearings the normal oil temperature rise as it gets squeezed and sheared by going through the bearing is around 30~40F ... not a rise of 250+F. (200F to 450+F).

In order for the bearing to raise the oil temperature inside the bearing to 450+F, the clearance would have to be very very small, and besides if oil the localized oil temperature is raised to 450+F the MOFT will go to zero and the bearing will literally smoke itself with metal-to-metal contact. That's why I don't believe that theory.

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