BBQ tick and oil change oil starvation

Discussion in 'Issues, Repairs, Warranty, TSB, Recalls' started by accel, Nov 5, 2018.

  1. Condor1970

    Condor1970 Well-Known Member

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    I agree. Especially since Chevrolet actually released a TSB notice explaining the same sound in high compression diesel engines being oil flashing/cavitation. In fact, I've even heard videos now of the Toyota 3.5L Tacoma engine ticking during test drives. Same noise from an engine that runs close to 11:1 compression ratio.

    My other thought is it really seems quite related to lower oil pressures at lower rpm. Most common item in that scenario would be sluggish Lash Adjusters when oil pressure is below 25psi. if you don't have quite enough pressure, it makes sense that a tiny gap may appear to the lifter arm temporarily until rpm/pressure gets high enough.

    What I'd like to know, is if I can get my computer controlled oil pump to maintain a higher 30psi pressure at idle, instead dropping all the way down to 15psi.
     
  2. GT Pony

    GT Pony Well-Known Member

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    #47 GT Pony, Nov 27, 2019
    Last edited: Nov 27, 2019
    Not totally sure about the cavitation theory. There are some things on how the BBQ tick behaves in the Coyote that don't seem to line up with the lab testing of cavitation in a journal bearing. More about that below.

    Also, Ford says in the BBQ tick SSM 7718 that the ticking can show up after the oil hits 150 F or above, and is heard between idle and 1700 RPM. From the report conclusions that seems to act opposite of the testing. In the test they found that thicker oil causes more cavitation, so seems the BBQ tick would be worse before the oil hit 150 F. And the testing showed that higher RPM caused more cavitation, so that would say the ticking should be worse at higher RPM, not at idle where a lot of guys hear it. But increased oil pressure should help prevent cavitation, so could be as the oil pressure increases with RPM any cavitation might be reduced or stopped. Many factors going on.

    And I'd like to know the mechanism of how small amounts of carbon, Motorcraft XL-17 (5% max concentration of carbon black in an 8 oz bottle, per the MSDS) and Ceratec changes the oil properties enough to have such a big effect on cavitation. Seems to me the ticking is something that is effected by the friction level between moving parts, and if the level of friction is increased then the ticking can get set off. Adding an anti-friction modifier reduces the friction level and the ticking goes away. Also, some guys have reported that the tick was still gone after using Ceratec and doing an oil change without adding Ceratec again, so the friction level between parts was still lower due to the previous use of Ceratec, as Ceratec advertises. The report didn't study the oil formulation or additives affect on cavitation, nor did they study the bearing clearance affects on cavitation,

    Also, the Ford SSM 7718 says that the ticking is "not detrimental to engine durability". But if you study cavitation in journal bearings, the cavitation can erode (due to implosions of vapor cavitation bubbles) the bearing surfaces and cause pretty bad damage with time. So that doesn't correlate with Ford's SSM statement. I still lean towards it being clearance and oil friction level related, especially since not all Coyotes have the BBQ tick. And if it was indeed cavitation, I'd sure think more than just a handful of engines in the world would have cavitation in journal bearings, as most crankshaft and rod journal bearings are all designed pretty much the same these days.

    Based on the conclusions in the test report (from Section 5 - see below):

    - Cavitation increases with increased oil viscosity. (1)
    - Increased RPM should cause more cavitation. (2)
    - Increased oil pressure should cause less cavitation. (2)
    - Change in oil pressure has more effect on cavitation than change in RPM. (2)

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

    5. Conclusions
    The cavitation shape, the oil film rupture and reformation
    location, and the cavitation area of the spiral
    oil wedge sleeve bearing are studied theoretically
    and experimentally for both the high viscosity lubricant
    and the low viscosity lubricant.

    (1) The cavitations are strip-shaped for both the
    high viscosity lubricant and the low viscosity lubricant,
    with the cavitation leading end in a closed angle, and
    in the oil film rupture region, oil bubbles are produced
    at a high speed. The cavitations for the high viscosity
    lubricant is distinct, but the cavitations for the low viscosity
    lubricant is indistinct.


    (2) With the increase of the rotating speed, the
    cavitation area of the oil wedge becomes larger for
    both the high viscosity lubricant and the low viscosity
    lubricant, with the increase of the input pressure, the
    cavitation area of the oil wedge decreases for both the
    high viscosity lubricant and the low viscosity lubricant,
    the effect of the input pressure on the cavitation is larger
    than that of the rotation speed generally.

    (3) The cavitation area decreases and the quality
    of lubrication is improved for the low viscosity lubricant
    compared with the high viscosity lubricant.

    (4) The experimental results agree with the theoretical
    results generally, which shows the theoretical
    computation is valid.
     
  3. BlackandBlue

    BlackandBlue Well-Known Member

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    There are far more questions than answers on this subject.

    My engine ticks on cold start but it’s not even noticeable when warm. This seems to be the opposite of what Ford is seeing.

    A small amount of suspension in a substance can change the cavitation properties due to disrupting the surface tension of the cavitation bubble. Basically you create smaller bubbles instead of one large one. The cavitation will still happen just many small events instead of a large one.

    I don’t believe it is a bearing surface creating the cavitation. Ford did change the rod bearing in the 2018 motors so this goes against my argument but bearing cavitation like you said would create erosion of the surface. This would be easily seen in an engine with the tick. The cavitation would have to occur where two sharp surface intersect or where fluid is forced to move faster than its surface tension will allow. Between two rods on the same journal or against the crank would be more likely. Cold the rods may walk farther than when warm creating this situation. Hardened metals resist cavitation much better than soft bearing so seeing the signs would be harder.

    Long story short is cavitation is just the only theory I can get to work.
    1. Clean oil
    2. Completely random.
    3. Cold start
    4. More pronounced on 2018+
    5. Same location on most engines.

    Differences in 2018 engine
    1. Direct injection
    2. Harder bearings.
    3. Changed pistons
    4. 10 quart plastic oil pan
    5. Larger bore.

    I just can’t find a theory that checks all the boxes besides cavitation. Some check a few. Only one checks them all.
     
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  4. Condor1970

    Condor1970 Well-Known Member

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    My thought on the cavitation theory is not necessarily cavitation "inside" the bearing, but more like "flashing" as the oil exits the sides of the big ends and makes a noise due to a rapid drop in pressure when expelled from the bearing or rod end itself. The words "flashing" and "bubbling" is used in the Chevrolet TSB explaining this ticking noise in the diesel engines under higher compression. Ford Powerstrokes also exhibit the same random ticking. In fact, so do Cummins, but nobody really notices it because they're so noisy to begin with.

    If not oil flashing, then I really think it's the lash adjusters.
     
  5. GT Pony

    GT Pony Well-Known Member

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    That noise may not really be the BBQ/typewriter tick. Could be slight piston slap since you have a 2018, since that's how piston slap behaves. I had a Corvette that did just as you describe, and it was definitely piston slap until the engine heated up some.

    Links to technical source(s) supporting that theory? I've never been able to find experimentation that supports that.

    No mention of the affect of oil formulation or oil additives on cavitation ... I can never find any info on that. Here's some good discussion on journal bearing cavitation.

    https://rotorlab.tamu.edu/me626/Notes_pdf/Notes06 Liquid cavitation model.pdf

    Notice it talks about cavitation is much more likely when more trapped air is in the oil. Maybe if the oil becomes aerated somehow (bad oil pickup tube seal as mentioned before?) then that sets off some cavitation. Some oils also "foam" more than others when being bashed around inside a running engine, and "foaming" is actually it becoming aerated from being bashed around by parts.

    If it's cavitation then it's going to be happening inside the journal bearings in the zone where the pressure drops down enough to cause air bubble trapped in the oil to implode, not between two rods on the same crank journal. The more aerated the oil is, the more likely for cavitation to happen inside the bearings.

    And if rod side clearance is the culprit, then it kind of makes sense that the ticking goes away after someone beats their engine pretty hard and heats up the crank and rods (a few guys here have reported that), which might close the rod side clearance just enough to quiet the ticking. If the rod big ends can dance side to side more, then it's still possible that they get triggered to dance dependent on the level of friction between them. If it's "oil flashing" as it comes out of the rod bearings, maybe that "flashing" causes some kind of instantaneous side force on the rod big ends that caused them to dance side-to-side at certain RPM ... ??

    I don't really see how a very small amount of anti-friction additive is going to almost instantly stop the ticking if it's caused by cavitation, especially if the the cause of the cavitation is oil aeration. That's why I think it still points back to a friction level between moving parts related issue.

    I think there are some missing signs to conclude it's all from cavitation or all from parts clearances, or all from lazy HLAs like Condor1970 thinks. Who knows, might be a combo of all of that. It's no doubt like trying to prove Bigfoot exists. You see the footprints, but never see Bigfoot. lol.
     
  6. BlackandBlue

    BlackandBlue Well-Known Member

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    It is funny that they use flashing or bubbling when that is just other words for cavitation. Cavitation is when you run a liquid past it’s ability to move out of the way creating a low pressure area that basically created a vacuum strong enough to rip open any air in the fluid. The bubble then collapses at speeds close to supersonic creating a pop. It’s the collapse and shockwave that does the damage.

    I most defiantly have the tick. It emanates only from the passenger side bottom of the engine. Cold it’s very noticeable. Warmed up about 5 mins and it’s almost completely gone. You can still hear it ever so slightly and very intermittently from the same spot.

    I don’t have any technical information. What I have played with extensively is jet boats and jet outboards. They both suffer from cavitation damage. You can hear and feel cavitation in a jet boat as it unloads the prop. What we have noticed is dirty water (muddy) doesn’t have cavitation problems like clean water. It will still cavitation it just takes most throttle to do it. We have always suspected it’s from the suspended particles in the water.

    But no I don’t have any real information other than antidotal experience.


    I complete agree. It’s not a perfect theory. Just the best one I have. The biggest problem with it being mechanical is it comes from the exact same spot every time. I have listened with a mechanics stethoscope and the sound is always in the same spot.
     
  7. GT Pony

    GT Pony Well-Known Member

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    From what I recall, most guys with the BBQ/typewriter tick say it shows up after the engine warms up, just like what Ford's SSM says. Ford must have put that in the SSM for some reason.

    If the noise comes from the same spot it could be mechanical. Seems to me that makes it more likely to be mechanical instead of cavitation. If it was cavitation seems like any rod or crank bearing could cavitate, so if it was cavitation the ticking could be all over the place on the bottom end.

    Does your ticking come and go at idle when the AC is turned on and off? Does it tick with the AC on, and doesn't tick with AC off? Many guys have reported that characteristic.
     
  8. Dfeeds

    Dfeeds Well-Known Member

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    I figured I'd just use the most recent bbq tick thread instead if making my own. A gt350 owner has the bbq tick and their dealer poked around a bit because it's the 350 and not a GT.

    Here's the thread https://www.mustang6g.com/forums/threads/2019-5-2-voodoo-bbq-typewriter-tick.133708/#post-2755881


     
  9. Condor1970

    Condor1970 Well-Known Member

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    So, according to that dealer, it is some sort of pressure drop causing a flashing of oil giving a tick/popping sound? Interesting.

    Now, if only I could get my oil pump reprogrammed to maintain 30psi at idle, instead of 12-15psi. :crying:
     
  10. GT Pony

    GT Pony Well-Known Member

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    That would be a good data point to have. Using the same oil & viscosity at the same oil temperature, then somehow increase the oil flow; ie, make that ECU controlled oil pump send more oil to the engine while at the same exact engine RPM, would tell if ticking noises changed with increased oil supply.
     
  11. Condor1970

    Condor1970 Well-Known Member

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    it would be a good way to find out. And here I was ranting on about the HLA's. Although, even if increasing oil pressure makes the tick go away, it still wouldn't answer the question of whether it's HLA's or oil flashing. But I wouldn't complain at that point, as long as it no longer makes noise. :)
     
  12. Dfeeds

    Dfeeds Well-Known Member

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    You were on the right track. It also would explain why my tick went away when I dropped to 5w20, from 5w30. For all we know the dealer got their info from Ford, hence their tsb on it. It's a good enough answer for me, right now, and reinforces my peace of mind. The 5.0 being more prone to it is probably just due to it being subject to looser manufacturing tolerances of parts.

    It does have me revisiting the whole argument that there's no clearance changes and the "5w20 is for cafe."
     
  13. GT Pony

    GT Pony Well-Known Member

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    There are guys who say their tick was gone or better/reduced by going with thicker oil too, so pinning it solely on oil viscosity is pretty random.

    And yes, Ford and all other manufacturers go thinner and thinner because of CAFE. All you have to do is look at what those companies spec for the same engines in other countries, and those engines have the same exact clearance specs.
     
  14. Condor1970

    Condor1970 Well-Known Member

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    #59 Condor1970, Dec 29, 2019
    Last edited: Dec 29, 2019
    I was thinking about this last night. I suppose that popping noise from flashing could be caused during the unloading of pressure on the rod as it rotates around after combustion. As that force/pressure on the bearing is rapidly released on an up-stroke during valve exhaustion, I suppose it could cause oil to flash in that moment. Must only happen on the number 3 or 4 piston due to location with lowest oil pressure. This would also explain why it stops when you pull the ignition coil on that one cylinder.

    I suppose it also explains why it happens more often with the newer 2018+ GT with higher compression ratios.

    It would also explain why guys are pulling bearings and doing measurements with no excessive wear, since it occurs on the unload moment of crank rotation....

    Just tossing out some thoughts here...
     
  15. GT Pony

    GT Pony Well-Known Member

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    The only problem I have with the whole oil cavitation or oil flashing theory is why does it occur on only some Coyotes? If the ticking was a result of the engine design, then I'd think they all should be ticking, or at least even more cases than what's been reported. That's why I keep thinking the ticking is related to parts clearances and the level of friction between moving parts, and why Ceratec cures the ticking nearly instantly, that is as soon as it takes to change the friction level shortly after adding Ceratec.

    Also, there are a lot of high compression and high performance motors in the world, and there is no indication of them all ticking because of their level of compression or performance level. And doesn't the Voodoo have higher compression than the Coyote, yet we rarely hear of a BBQ ticking Voodoo.

    It's good to look at all viewpoints from all, and always appreciate your comments Condor.
     
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