BBQ tick - another attempt to understand

[GT Pony]

I personally don't buy rod side clearance as the source for the BBQ tick. With proper oil pressure, the oil 'bleeding' between the rods and the crank journal edges would prevent any contact anyway. Generally, excessive rod side clearance just causes more oil to be able to gather at that joint and be flung up against the bottom of the piston and thus the engine MIGHT be more apt to use a little more oil. In an extreme instance, I could see excessive rod side clearance causing oil pressure issues, but the clearance would have to be crazy wide. I used to set up race engines on the loose side with a high volume oil pump, zero issues.

The volume of oil flowing through the journal bearings is function of the bearing clearance - not the rod side clearance. The bearing clearance is the "choke point" of the oil flow path, and has much less flow area than the rod side clearance. The only thing that causes more oil to fling out the side of the rods is: 1) larger bearing clearance, 2) higher RPM and 3) higher oil supply pressure to the bearing. The only way for the rod side clearance to be the point of oil flow control ("choke point") is if the total rod side clearance flow area was less than the bearing clearance. If that was the case, the rod big end bearing and side clearances setup would have to be totally messed up.

The "larger rod side clearance gives more oil flow and fling off from the bearing" is a misconception.
https://www.hotrodders.com/forum/connecting-rod-clearance-question-124014.html#post865150

Someone that found excessive rod side clearance resulted in "clattering" noises at idle.
https://turbobuick.com/threads/rod-side-clearances.150914/#post-1048888

The frequency of the tick in the videos I've watched all seem to point at something related to valvetrain...

The BBQ/typewriter tick has no real repeatable frequency ... it's pretty random.

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[Strokerswild]

I never stated that excessive rod side clearance would increase flow to that joint. Only that a gap leaves a place for a slightly larger volume of oil to collect and be flung off, etc. As for it being a misconception, well, rod journal sling is largely how cylinders are lubricated in general. Eons ago the local college engineering lab had a V8 (IIRC, a SBC) in a dyno cell with little plex windows epoxied in the lower block for observing oil control. Interesting stuff to watch.

Agreed on the random nature. It's weird. I'd love to actually see/hear an afflicted engine first hand.

I've never heard any connecting rod-related noise that sounds quite like the BBQ tick. It's pretty loud, reminds me of a failing cam follower that's taking out the cam lobe, yet intermittent at times. Then again, I haven't experienced the sound of a failing powdered metal connecting rod coming through an aluminum block either.

 

[bootlegger]

Of course they do....

STP? Really?

STP doesn't actually make their own additives. They are a blender and bottler. They buy the additives from chemical companies who actually do testing and development. STP does use legitimate stuff in their bottles, but the company is a shell of its former self.

 

[GT Pony]

I never stated that excessive rod side clearance would increase flow to that joint. Only that a gap leaves a place for a slightly larger volume of oil to collect and be flung off, etc.

I doubt oil is going to "gather" in the rod side clearance gap. Oil volume flows through the journal bearing based on the bearing clearance, oil viscosity, supply oil pressure and engine RPM. Any oil that flows through the bearing clearance and out to the side clearance gap instantly gets flung out of the gap from the rotating rod, regardless of how much rod side clearance there is.

 

[SlaughterOfTheSoul]

Exactly. Excessive rod side clearance. Torque thrust the crank and the rod clearance diminishes and so does the tick.

What's the spec for thrust bearing clearance?

What's the spec for rod clearance?

Thrust bearings should not typically have enough play to make a difference without indicating something wrong with the thrust bearing. You can measure the thrust bearing end play of the crank by tapping the crank pulley back with a rubber mallet typically, then measuring how much the crank moves forward when someone presses the clutch. For most cars this spec is thousandths of an inch but I don't know for sure for the coyote.

It could be excessive thrust bearing clearance causing wear on the rods, but still the main issue would be undersized thrust bearing surfaces.

 

[Condor1970]

+You know. I'm starting to think all my theories were wrong from the get-go.

Something interesting I made note of today. When I start the car, initial oil pressure is 40psi, and slowly drops down to 15psi as rpm drops and oil warms up. As soon as oil pressure reaches 30psi and dropping during warm up, I hear a few odd ticks. Then, as pressure reaches 25psi, the ticking is pretty constant. When I tap the gas at this pressure and it bumps up to 30psi and only 1,200rpm or so, the ticks go away.
As the engine gets fully warmed up, It ticks like crazy at 15psi idle. Then, as I rev the engine the ticking is very noticeable all the way up to about 2,500rpm. Guess what happens at 2,500rpm? Oil pressure reaches about 30psi, and the ticking goes away. As soon as the oil pump bypass closes and pressure jumps to 80psi, no more ticks.
Now, this is without Ceratec. As soon as I start adding Ceratec, the ticking slowly gets quieter as I add more until I get to about 1/2 bottle.As lubricity slowly gets better, whatever is ticking, slowly starts operating more smoothly.

I'm starting to think this typewriter ticking has more to do with low oil pressure to the HLA's than anything else. And, it most likely occurs in one particular area of the engine where pressure is lowest at certain lash adjusters. My guess would be around cylinder 3.

Just another theory. But to me it makes more sense than anything else at this point.

 

[GT Pony]

^^^ Could be. But could also be that thinner oil and low oil pump output pressure at idle and low RPM with hot oil affects how the rods may dance side-to-side on the crank journals.

Fact that even a small dose of Ceratec causes the ticking to go away says it's a mechanical issue that's affected by the friction level going on between moving parts.

 

[Berk.s550]

True. I brought my ticking 17 GT to the dealer and they think it has to do something with the valve train or timing chain. They already changed the timing chains and tensioners which did not change anything.

Based on my observations I cannot believe it has got anything to do with the valve train. It has to be on the bottom end, maybe excessive rod or crankshaft clearance, as some suggest. It certainly sounds as coming from the bottom of the engine.

My engine does not tick at idle. It does it when cruising with constant speed at 1400-2000 rpm. What makes me think it’s rod/crankshaft related is this:
If you give it just a little bit more throttle (accelerating very slowly), the ticking disappears instantly. Same if you let off the throttle a bit. It’s perfectly reproducible on my daily trip to work. I’m driving with cruise control at 35mph in 4th (MT) and it ticks. Now I approach a small incline and cruise control has to apply some more throttle to hold speed and the ticking is completely gone immediately. After the incline the tick returns.

My theory is that due to excessive clearance the rods clatter in lateral direction. When some lateral force is applied to the crankshaft via the clutch/flywheel, it is pushed every so little in lateral direction so the rods cannot clatter, because they cannot move freely anymore.

I cannot imagine how the instantly disappearing of the tick could be explained if it was valve train related.

Also, an analysis of the oil that was 5000 mls in the engine showed 4mg/kg of lead. This is not very much I’m being told, but I believe lead is in the rod and crankshaft bearings, so another hint here?

Now I’m trying to convince my dealer that he does some investigation in that direction but he insists on concentrating on the valves further.

Tom

I have the exact same issue. Any update on what was causing the sound if you found out?

 

[TomW801]

I have the exact same issue. Any update on what was causing the sound if you found out?

Hi,
this is a long story. They found out that one of the camshafts had lateral play, changed the camshaft and the phasers, but no luck. Then replaced the complete right cylinder head and declared the issue as fixed.
It is not completely gone now, but much much better. I hope this will still be the case next summer when the temperatures get higher, because it always was worst in high temperatures.

 

[accel]

+You know. I'm starting to think all my theories were wrong from the get-go.

Something interesting I made note of today. When I start the car, initial oil pressure is 40psi, and slowly drops down to 15psi as rpm drops and oil warms up. As soon as oil pressure reaches 30psi and dropping during warm up, I hear a few odd ticks. Then, as pressure reaches 25psi, the ticking is pretty constant. When I tap the gas at this pressure and it bumps up to 30psi and only 1,200rpm or so, the ticks go away.
As the engine gets fully warmed up, It ticks like crazy at 15psi idle. Then, as I rev the engine the ticking is very noticeable all the way up to about 2,500rpm. Guess what happens at 2,500rpm? Oil pressure reaches about 30psi, and the ticking goes away. As soon as the oil pump bypass closes and pressure jumps to 80psi, no more ticks.
Now, this is without Ceratec. As soon as I start adding Ceratec, the ticking slowly gets quieter as I add more until I get to about 1/2 bottle.As lubricity slowly gets better, whatever is ticking, slowly starts operating more smoothly.

I'm starting to think this typewriter ticking has more to do with low oil pressure to the HLA's than anything else. And, it most likely occurs in one particular area of the engine where pressure is lowest at certain lash adjusters. My guess would be around cylinder 3.

Just another theory. But to me it makes more sense than anything else at this point.

If you have manual, first without ceratec in the engine,- push clutch pedal to the floor and hold, play with rpms at the same time. See if you notice any feel on the pedal that correlates with the tick. In my case I could always correlate some mechanical disturbance through clutch pedal that would be there at the the engine ticks. Hard to describe, but like if something pretty heavy is rotating with very little lubrication, and so you feel mechanical interaction of some sort. It is pretty noticeable and I do not think I felt anything similar in my prev 3 pedal cars.

After that add ceratec. That thing I used to feel through the clutch is gone.

It was reproducible for me on the ticking block and then at the brand new block, that was not ticking. I added ceratec right away as I didn't want to hear new short block ticking again.

 

[Condor1970]

If you have manual, first without ceratec in the engine,- push clutch pedal to the floor and hold, play with rpms at the same time. See if you notice any feel on the pedal that correlates with the tick. In my case I could always correlate some mechanical disturbance through clutch pedal that would be there at the the engine ticks. Hard to describe, but like if something pretty heavy is rotating with very little lubrication, and so you feel mechanical interaction of some sort. It is pretty noticeable and I do not think I felt anything similar in my prev 3 pedal cars.

After that add ceratec. That thing I used to feel through the clutch is gone.

It was reproducible for me on the ticking block and then at the brand new block, that was not ticking. I added ceratec right away as I didn't want to hear new short block ticking again.

I have not noticed any real appreciable feel through the pedal. Whatever is impacting to make the noise would pass through everything solid. So, if you are feeling something, the impact could be from almost anything in the engine. I don't doubt that you're feeling something. Only problem is, there's no way to tell exactly what it is, imo.

 

[VinnyVicci]

I have a 2019 mustang gt pp1. I purchased the car in March and I first heard the tick at about 1k miles. I did break the engine in the way the manual says. I did the first oil change at 2k with Mobil 1 full synthetic 5w30. The car didn’t tick right after the oil change. The car ticks sometimes then goes away. If I drive the car everyday or every other day...no tick. If I haven’t driven the car in 3 days after cold start when the engine warms up it ticks for 10 min. I then drive the car and I won’t hear the tick all day. The more I drive it the less it ticks or no tick at all. The one thing I’ve noticed is when it does tick,it seems that when the oil pressure rises, it stops on warm oil. I check my oil and no oil consumption or metal shavings and no power loss. I’m stumped.

 

[Berk.s550]

Tick fixed. 5w30 oil.

2017 Mustang GT, ticking between 1-2k rpm. It would come and go. It happened a lot and I could reproduce it a majority of the time. Would usually go away or be very quiet when the car was hot. It would come back when the car was cold sometimes or when the car was hot then turned off for an hour or so. It would only really happen if you held the rpms at that level or cruised with rpms there.

Sounded just like this:

I was not trying to cure the tick. I decided to use 5w30 for other reasons. I threw 5w30 oil in and the tick was gone instantly. Hasn’t come back since. Haven’t heard even the slightest sign of it. I’ve come to the belief that 5w20 is too thin for these engines and that is perhaps why odd sounds are occurring.

 

[Condor1970]

Tick fixed. 5w30 oil.

I was not trying to cure the tick. I decided to use 5w30 for other reasons. I threw 5w30 oil in and the tick was gone instantly. Hasn’t come back since. Haven’t heard even the slightest sign of it. I’ve come to the belief that 5w20 is too thin for these engines and that is perhaps why odd sounds are occurring.

Mine sounds exactly the same way with full synthetic QSUD 5w30, and PUP 5w30. In fact, it still ticks a little with only 1/2 bottle of Ceratec. I may just start putting in a whole bottle each oil change.

 

[TnWHTMARE]

Same here with Mobil 5w30 and Driven 5w30

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