BBQ tick - another attempt to understand

[GT Pony]

I doubt Ford puts anything special in the factory oil fill. Lots of guys have reported that their engine started doing the BBQ tick on the factory oil before the first oil change was done.

Some guys also have reported that their engine started doing the BBQ tick after an oil change, but then the tick slowly went away as the miles went on the oil. In that case, I believe the anti-wear additive layer was slowly building up on parts, and then at the next oil change that layer gets stripped off by the new oil.

There has been lots of talk on bobistheoilguy about the anti-wear layer getting stripped off with an oil change and it has to build back up from the new oil over time. Even been research done and technical papers written showing that more engine wear can result from doing frequent oil changes because of the stripping of the built up anti-wear layer by new oil.

https://www.sae.org/publications/technical-papers/content/2007-01-4133/

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[Jimmy G]

.... The engine is out and apart and the tech determined that it was excessive rod side clearance. After measuring he found that the rod side clearance was over double spec, on two different bearings. Spec is .325mm to .5mm. Two of mean measured close to .9mm. He showed it to me and it was very evident. Had a lot of side to side play and made the exact typewriter tick noise when moved side to side by hand.......

Interesting, but that's not what's caused the typewriter tick.

I know this how? Well, a bottle of gunk poured into the oil cap will not solve the issue of excessive rod side clearance and since that stuff does fix the tick, the tick isn't caused by excessive rod side clearance. Your engine is out, your car is in the shop, and when you eventually get it back with the new short block you'll join the lottery again and be no further ahead. All you've gained is a month of Mustang free motoring.

The tick is caused by big end bearing stack tolerance. It's a non-issue (mechanically)....we know this because 5.0 engines have ticked for a hundred thousand miles.

 

[GT Pony]

Did they find excessive wear marks on the sides of the big end or crankshaft?

If not, was the tick always there, or did it develop over time?

I ask, because I can't see very well, and it doesn't look like it has a ton of wear marks on the crankshaft. If it has no visible wear, then the excessive clearance was there from the factory, so the tick should have been there from day one of ownership. If the tick developed over time, how the heck could the noise be that?

I think it has more to do with the friction between the sides of the rods, and maybe the cushioning aspect of the oil acting with the excessive side clearance. That is why putting Ceratec in the oil almost instantly makes the BBQ tick go away - less friction (explained below) and maybe more parts impact cushioning. There probably won't be much wear caused by the action of the rods sliding side-to-side on the journal and making contact, probably just shine up the side edges of the rod some. You'll never see any medal debris in the oil or in the filter from it.

It's possible that if the friction gets too high on the side of the rods that causes them to randomly jump around side-to-side on the crank journal and clank against the ends of the crank journal - just like is seen in the videos posted of the guy sliding the rod back and forth on the journal and making it tick.

This is just my theory ... really wish there was a way to prove it. That's why I came up with the idea of maybe the ticking would change or stop if the engine was on a very steep hill (engine pointed up a lot) to make the rods all sit to one end of the journals.

 

[GT Pony]

Interesting, but that's not what's caused the typewriter tick.

I know this how? Well, a bottle of gunk poured into the oil cap will not solve the issue of excessive rod side clearance and since that stuff does fix the tick, the tick isn't caused by excessive rod side clearance. Your engine is out, your car is in the shop, and when you eventually get it back with the new short block you'll join the lottery again and be no further ahead. All you've gained is a month of Mustang free motoring.

The tick is caused by big end bearing stack tolerance. It's a non-issue (mechanically)....we know this because 5.0 engines have ticked for a hundred thousand miles.

On the same token, Ceratec shouldn't make excessive big end stack tolerance become quiet either. But Ceratec certainly has made the BBQ tick go away for many here that have used it.

 

[GT Pony]

My car went into the shop for the typewriter tick about a week before the tsb was released. Glad I brought it in when I did. The engine is out and apart and the tech determined that it was excessive rod side clearance. After measuring he found that the rod side clearance was over double spec, on two different bearings. Spec is .325mm to .5mm. Two of mean measured close to .9mm. He showed it to me and it was very evident. Had a lot of side to side play and made the exact typewriter tick noise when moved side to side by hand. Ford approved a short block.

I'm not sure if the new short blocks come with an oil pan on them or not. If not, you should have your mechanic check the rod side clearances on the new short block just to ensure they are all within specs.

 

[Supersolo]

Not sure if anyone watched the Palm Beach Dyno video, a walk through the MPR Racing workshop?

I discovered that video via comments posted on a YouTube video on the Coyote CarGuy channel.

I was particularly interested by the comments made by a gentleman, regarding the blue-printing process and how in the case of the Gen 3, there was a dimensional issue to address.
That part of the conversation did drift onto the subject of the Gen 3 type writter tick, the conclusion of the engine builder being that the sound was piston slap.
If I recall correctly (I'll have to go watch the video a few more times) the opinion was the engine block "grows"/"expands" by a comparitively large amount.
Comments also alluded to the specification of the aluminium used for the block was not what it might once have been.

After listening to the opinion of someone working on these engines, my conclusion so far is as follows:

For reasons of cost, Ford may have decided to use a lower spec material for the engine block at the "risk" of the block exhibiting significant thermal expansion.
To contain this Ford may have elected to allow the big-end to "float" along the axis of the crank. This might address longitudinal thermal extension of the engine block, but would also permit the piston not to reciprocate "square" in the cylinder.

Obviously this situation could give rise to a prematurely and excissively worn bore/piston interface, as we saw in the U.K. V8 in Manchester, where compression testing identified lower than average readings in two cylinders.

Until recent posts ^^ I had always thought the type writter tick ocurred only after the 1st engine oil change, however, it would now appear some unfortunate folk are getting the type writter tick before the factory engine oil is changed.

The type writter tick ocurring before the 1st oil change would be consistent with my conclusions above.
Furthermore, the opinion of the engine builder in the video commented that the stack tolerances were on the large side, it seems. Which then precipitated the comment not to rev the Gen 3 at all, before reaching normal operating temps.

Then we see that blue printed and sleeved engines do not suffer the type writter tick and so it seems to me we are looking at piston slap, brought about by excessive thermal expansion of the block, resulting in components moving out of alignment or beyond tolerance, wearing excessively, resulting in audible piston slap.

My car, if it ever arrives, should be with me in the next few weeks.
I have paid for & taken delivery of an oil sampling kit. I intend to sample the engine oil with "delivery miles" on the car, which is the best I can do as to try to understand what Ford is filling the engines with during manufacture.

Meanwhile I am conflicted about whether to use a friction reduction additive, "straight off the bat".
My thoughts are, if I do, I void my warranty.
However, if I do not do anything but run-in on the factory oil, I appear to run the risk, as high as 40%, that my car may develop the type writter tick.
If that happens, Ford may only replace with an engine which again is at a higher than usual risk of also developing the type writter tick.
Although this is now seemingly less likely as Ford are beginning to try to fob us off by claiming the type writter tick is "normal".

I am an automotive design Engineer, I have worked on Ford projects, but I have very little power train experience.
However, I do not expect a new engine to develop piston slap so soon after manufacture, nor any corresponding loss of output, from the engine having piston slap.

As I sit here and read this, it's difficult to try to ignore my own sense of logic telling me I should perhaps reconsider my purchase!

 

[88lx50]

OK not to sound stupid but somebody school me on big end bearing stack tolerance.

 

[bootlegger]

The tick is caused by big end bearing stack tolerance. It's a non-issue (mechanically)....we know this because 5.0 engines have ticked for a hundred thousand miles.

I don't think we know this.

 

[Superchomper2003]

Interesting, but that's not what's caused the typewriter tick.

I know this how? Well, a bottle of gunk poured into the oil cap will not solve the issue of excessive rod side clearance and since that stuff does fix the tick, the tick isn't caused by excessive rod side clearance. Your engine is out, your car is in the shop, and when you eventually get it back with the new short block you'll join the lottery again and be no further ahead. All you've gained is a month of Mustang free motoring.

The tick is caused by big end bearing stack tolerance. It's a non-issue (mechanically)....we know this because 5.0 engines have ticked for a hundred thousand miles.

I fail to see how it could silent big end bearing stack tolerance but not cushion the slight side to side tapping of too much side play. I think I’ll have gained more than a month without mustang, Even if the tick returns, The parts are out of spec, so obviously that’s an issue, so hopefully I will gain an engine that is in spec.

 

[GT Pony]

For reasons of cost, Ford may have decided to use a lower spec material for the engine block at the "risk" of the block exhibiting significant thermal expansion.
To contain this Ford may have elected to allow the big-end to "float" along the axis of the crank. This might address longitudinal thermal extension of the engine block, but would also permit the piston not to reciprocate "square" in the cylinder.

The Coyote has always had free floating rods on both the big end and at the wrist pin. All engines have some amount of big end side play.

Pistons can only move around in the bore as much as the piston to bore clearance will allow, and what the big end and wrist pin clearance will allow. If the big end and wrist pin clearances are in spec it leaves very little room for the piston to move around (rotate) about the longitudinally axis of the rod.

But since the rods are full floating on both ends, the rods can certainty move side to side and bang againt each other (4 pairs of rods in a V8) or against the ends of the crank journal shoulders.

 

[Condor1970]

The Coyote has always had free floating rods on both the big end and at the wrist pin. All engines have some amount of big end side play.

Pistons can only move around in the bore as much as the piston to bore clearance will allow, and what the big end and wrist pin clearance will allow. If the big end and wrist pin clearances are in spec it leaves very little room for the piston to move around about the longitudinally axis of the rod.

But since the rods are full floating on both ends, the rods can certainty move side to side and bang againt each other (4 pairs of rods in a V8) or against the ends of the crank journal shoulders.

^^^Logical. One question though.

If the noise is something that develops over time, would it not then show obvious signs of wear on the big ends and crank shoulders?

I'm not hearing any reports or seeing any pics of that.

 

[GT Pony]

^^^Logical. One question though.

If the noise is something that develops over time, would it not then show obvious signs of wear on the big ends and crank shoulders?

I'm not hearing any reports or seeing any pics of that.

I don't think there would be any abnormal wear there. Rods on every engine ever made rub occasionally on the big end sides, even if they don't contact hard enough to make a noticable noise. The level of sliding contact in that ares is the same regardless of the clearance.

Just because it makes a noise from contact doesnt mean it's causing damage or significant wear. That whole area is flooded with oil due to the bearing side leakage.

 

[Condor1970]

I don't think there would be any abnormal wear there. Rods on every engine ever made rub occasionally on the big end sides, even if they don't contact hard enough to make a noticable noise. The level of sliding contact in that ares is the same regardless of the clearance.

Just because it makes a noise from contact doesnt mean it's causing damage or significant wear. That whole area is flooded with oil due to the bearing side leakage.

That's my point. If we are getting these cars new, and they do not make any noise, then it obviously shouldn't have a clearance issue with the big ends. Then, if the tick develops in a thousand miles of driving, logic dictates there needed to be some physical wear in order to open that clearance and make it start ticking.

If it does have a clearance out of spec, but no signs of wear, then why was it silent for a couple thousand miles before it started making noise? It should have been making a racket right off the assembly line. Something had to wear somewhere in order for the noise to start.

So, my point being, even if they pull the engine apart and find a big end out of tolerance with no signs of wear, then I have a sneaky suspicion it wasn't the source of noise. Especially if the noise didn't develop until much later.

 

[GT Pony]

If it does have a clearance out of spec, but no signs of wear, then why was it silent for a couple thousand miles before it started making noise? It should have been making a racket right off the assembly line. Something had to wear somewhere in order for the noise to start.

Same reason that Ceratec/XL-17 or a fresh oil change makes the tick disappear and appear. It has to be something related to the friction level & cushioning effect of the oil.

So, my point being, even if they pull the engine apart and find a big end out of tolerance with no signs of wear, then I have a sneaky suspicion it wasn't the source of noise. Especially if the noise didn't develop until much later.

I really don't think there's going to be any noticable wear from excessive rod side clearance. What causes wear is parts sliding against each other. The rods dancing side to side causing a slight impact and possibly a noticable ticking noise isn't adding any additional sliding wear, IMO.

 

[Condor1970]

Same reason that Ceratec/XL-17 or a fresh oil change makes the tick disappear and appear. It has to be something related to the friction level & cushioning effect of the oil.



I really don't think there's going to be any noticable wear from excessive rod side clearance. What causes wear is parts sliding against each other. The rods dancing side to side causing a slight impact and possibly a noticable ticking noise isn't adding any additional sliding wear, IMO.

I think you're missing my point. If big end clearance is not causing any wear, then why are the cars quiet when we buy them, then develop a tick thousands of miles later?

If the car is silent when you buy it, then there shouldn't be a clearance issue if that is the cause of the noise. If noise does develop down the road, then there should be obvious signs of wear in order to open up enough to cause some audible impact.

It doesn't make any sense.

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