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2018 Mustang GT owners : Listen to your engine for rattles..could be that...!!

Houston Kid

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So is it carbon build up or damage? I find it interesting that they are almost mirror images. Like the cylinder wall is so smooth it is actually a reflection and not damage on both? Just what I see when I look at the pic. Not disagreeing or trying to start any shit, just my laymen observation.
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Stormtroopin5.0

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So is it carbon build up or damage? I find it interesting that they are almost mirror images. Like the cylinder wall is so smooth it is actually a reflection and not damage on both? Just what I see when I look at the pic. Not disagreeing for trying to start any shit, just my laymen observation.
My opinion is damage to cylinder bore wall rather than carbon buildup. No crosshatch visible behind that streaking = no bueno.
 

growler

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i'm not sure why u would scope over leakdown if no leakdown nothing is wrong, even if there's pictures Kim Kardashian nekkid on the cylinder wall
 

Bald Menace

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The pistons do contact the walls at times, sometimes this will make marks similar to what the OP has pictured especially on the thrust side of the cylinder bore. the picture I posted below is of my dyno time only engine after tear down for inspection after dyno runs. note the polished marks. this engine made 1017 hp and had very expensive pistons and rings, it was bored and honed with Torque plates bolted to both decks and a main girdle. the marks were visual only and could not be felt by tool or hand. the engine was fine.
piston scuffing.PNG
 

200MPHCOBRA

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This is a big nothing burger. Bore is so shiny its reflecting the piston top. The lines are a shinier area of the bore on the thrust side of the bore. Only surprising thing is the texture of the piston top.
 

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Bald Menace

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This is a big nothing burger. Bore is so shiny its reflecting the piston top. The lines are a shinier area of the bore on the thrust side of the bore. Only surprising thing is the texture of the piston top.
yeah, thats a lot of carbon buildup. there's a thread with pics of the new 2018 engine here somewhere and the tops of the pistons are nice and shiny when new.
 

zackmd1

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So let me ask this.... Your car currently drives perfectly fine with no excessive oil consumption or compression leaks correct?

Why then are people so insistent/eager to have a Ford tech rip into their engine bay to replace the engine with a new one that has no guarantee of actually fixing the minor noise? You are just asking for more issues all for a slight noise that can be hidden by a louder exhaust/volume on the radio?

Yes the noise does sound bad but I am not convinced it will cause or even is the cause of excessive wear that will cause problems later on. Drive the car and enjoy it!
 

Mountain376

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And see this topic :

https://www.mustang6g.com/forums/showthread.php?t=102509


This is the picture I took this morning inside my cylinder#3 with my borescope :

big-7229149b07.jpg


Very slight rattle, hardly noticeable at first....

This is really bad as I see more an more people with this issue.

2018 Mustang GT PP1, 5200miles
What kind of pistons are in the Gen 3 Coyote? Are they hypereutectic or forged? Probably hyper... Curious where Ford puts the piston to wall clearances.

Anyway, those marks look pretty light and nearly nothing. This isnā€™t to say there is no issue, as no one knows how loud your ā€œlight rattleā€ is. But if leakdon is fine, or consumption is fine and the engine operates fine, I would keep running it.
 

boxstang40

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This reminds me of the early ls engine days lol. I actually still drive a 2001 tahoe to work with 217000 miles. It still rattles first minute or so, then nothing after that.
 

airfuel

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Remember the good old days before the internet, home boroscopes and general paranoia?

Strange noises were usually called piston slap and people would drive cars until they wore out, got crashed, sold or stolen.

If you blew a motor, it was sometimes looked at as a badge of honor!
ā€œI rode that engine so hard it blew!ā€
 

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Nabush

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So let me ask this.... Your car currently drives perfectly fine with no excessive oil consumption or compression leaks correct?

Why then are people so insistent/eager to have a Ford tech rip into their engine bay to replace the engine with a new one that has no guarantee of actually fixing the minor noise? You are just asking for more issues all for a slight noise that can be hidden by a louder exhaust/volume on the radio?

Yes the noise does sound bad but I am not convinced it will cause or even is the cause of excessive wear that will cause problems later on. Drive the car and enjoy it!
Iā€™m pretty sure a leakdown test would be good. Car drives fine and show no oil consumption FOR NOW.
My issue is that the rattle is now considerably more noticeable than before, to the point it annoys me. As you said, the mark is very light, which I donā€™t challenge. But if the piston clearance were good :

- I wouldnā€™t hear this rattle
- these marks wouldā€™nt be here

The coating on the cylinder wall is probably few hundreds to low tenth of millimeters thick(unless someone has the information). Any visible mark can expose bare aluminum. You guys need to forget your previous experiences of previous sleeved blocks, this new coating is not near as thick as these.

Personaly I donā€™t want to play with a $15000 dollars engine...

As far as clearance cylinder/piston I donā€™t have the number either.
 

BmacIL

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If you have no noticeable oil consumption, compression loss, don't worry, particularly if it goes away after it's warned up. The spray bore liner is a different beast than what people are used to. It has different mechanical and thermal expansion properties than a typical cylinder liner. Because of it being so thin in comparison, the diameter of the cylinder bore will more or less follow what the block does, vs a liner that expands slower than the aluminum it's pressed into. This can mean some piston slap before it's all warmed up, as seen on the GT350. Just don't drive it like you stole it from until you're up to operating temp (that should apply for any vehicle but you know what people do).
 
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Nabush

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If you have no noticeable oil consumption, compression loss, don't worry, particularly if it goes away after it's warned up. The spray bore liner is a different beast than what people are used to. It has different mechanical and thermal expansion properties than a typical cylinder liner. Because of it being so thin in comparison, the diameter of the cylinder bore will more or less follow what the block does, vs a liner that expands slower than the aluminum it's pressed into. This can mean some piston slap before it's all warmed up, as seen on the GT350. Just don't drive it like you stole it from until you're up to operating temp (that should apply for any vehicle but you know what people do).
Noise doesnā€™t go away when hot. Forged pistons on GT350, Hyper on the GT. This noise is Ā«*ok*Ā» on a GT350 when cold because of that.
 

Fatguy

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Iā€™m amazed at people who criticize others looking into potential problems on a relatively new engine that has zero track record. Sure if it was a 2017 you could say maybe wait and see before you press the panic button. But with a new manufacturing process in a critical area, all I can say is thanks to these guys for looking into it and bringing it to our attention. I was actually contemplating a move up to the 2018 as I figured that may be one of the most powerful V8s before they go extinct, but because of the timely input into possible problems I have put off that purchase. These guys may have saved me considerable grief. They are doing you a service in his Mustang community. So I for one applaud their efforts.
 

stevegt

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The spray in cylinder liner may be new to the 5.0, but it is not a ā€œnew processā€. Itā€™s been used on the GT500 since 2011.
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