Question about 18-19 5.0 engines

[CB18]

For members that had engines diagnosed with piston slap and bore scoped with cylinder scoring. Did metal particles show up in the oil and filter? Thanks, CB

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[ehazel]

Mine did have metal in the filter; Its currently sitting at ford getting a new short block.

 

[5OhSilver]

No scoring for me. Lots of metal "glitter" in the oil filter and my catch can. Long block replaced and now its back at the dealer for BBQ tick on the new engine. Fun time to be a Mustang owner lol.

 

[CB18]

I changed oil filter at 80 miles and changed oil and filter at 800 miles. I saved the oil and the filters with the oil from the filters. I don't see any metallic in that oil. Maybe the noise I'm hearing is the clutch assembly. The parts are ordered, just waiting on backorder.
If that new cylinder process is so hard, how is an aluminum piston scoring it?

 

[GT Pony]

If that new cylinder process is so hard, how is an aluminum piston scoring it?

Piston rings are very hard metal too. The "scores" seen on the cylinder walls may also be piston material embedded into the cylinder wall.

 

[CB18]

Some of the pictures I have seen of the scoring the rings would not go down that far. Why is aluminum getting into the cylinder wall?

 

[Cobra Jet]

I changed oil filter at 80 miles and changed oil and filter at 800 miles. I saved the oil and the filters with the oil from the filters. I don't see any metallic in that oil. Maybe the noise I'm hearing is the clutch assembly. The parts are ordered, just waiting on backorder.
If that new cylinder process is so hard, how is an aluminum piston scoring it?

Have you cut open any of those filters and unrolled the pleated element to check for metal?

See Ford doc:

 

[CB18]

No I have not inspected the filters. I have to get a tubing cutter from my buddy. All of my cutters are just shy of three inches capacity.

 

[Condor1970]

Piston rings are very hard metal too. The "scores" seen on the cylinder walls may also be piston material embedded into the cylinder wall.

And most of that embedded material is actually going to be Aluminum from the piston skirts, not the rings themselves.

 

[Condor1970]

Some of the pictures I have seen of the scoring the rings would not go down that far. Why is aluminum getting into the cylinder wall?

Because the piston skirt, which is below the rings, is what you see. As the piston rocks back and forth on the wrist pin, the skirt scrapes the sides of the cylinder wall, and the cross hatching of the PTWA liner is so hard that it will scrape aluminum off the skirt, and get embedded into the liner. For those that see tiny flakes in the catch cans, is probably because as the cylinder cycles downward, the hard rings may scrape some of the aluminum off the liner, and those flakes then get tossed airborne inside the lower half of the engine where some fall into the oil, and some gets sucked into the catch can.

 

[GT Pony]

Because the piston skirt, which is below the rings, is what you see. As the piston rocks back and forth on the wrist pin, the skirt scrapes the sides of the cylinder wall, and the cross hatching of the PTWA liner is so hard that it will scrape aluminum off the skirt, and get embedded into the liner.

The piston skirts are coated, so the coating would have to wear off before getting down to aluminum. If there's a problem with the piston skirt to cylinder clearance, I'd think these engines that have major rattling noise would show some obvious wear on the piston skirts.

https://www.mustang6g.com/forums/th...wire-arc-cylinder-liners.113071/#post-2395155

 

[Condor1970]

The piston skirts are coated, so the coating would have to wear off before getting down to aluminum. If there's a problem with the piston skirt to cylinder clearance, I'd think these engines that have major rattling noise would show some obvious wear on the piston skirts.

https://www.mustang6g.com/forums/th...wire-arc-cylinder-liners.113071/#post-2395155

They are. When they pull those pistons in the worn cylinders, the skirts all have the plating worn right off, down to the bare Aluminum. That plating in super thin, and only provides temporary protection from piston slap.
Otherwise, they are telling owners to just live with the bloody noise, because these pistons have very short skirts and have a tendency to slap right out of the factory. Once they start seeing actual metal in the filters and metal embedded in the cylinder walls, that's when it gets so bad, they start changing out blocks. I personally think it's a bit of an inherent design issue when they increased the bore diameter, but have no change in stroke length allowing for longer piston skirts to keep things more stable. That's why it seems to be so much more prevalent in the 2018's.

 

[GT Pony]

They are. When they pull those pistons in the worn cylinders, the skirts all have the plating worn right off, down to the bare Aluminum. That plating in super thin, and only provides temporary protection from piston slap.
Otherwise, they are telling owners to just live with the bloody noise, because these pistons have very short skirts and have a tendency to slap right out of the factory. Once they start seeing actual metal in the filters and metal embedded in the cylinder walls, that's when it gets so bad, they start changing out blocks. I personally think it's a bit of an inherent design issue when they increased the bore diameter, but have no change in stroke length allowing for longer piston skirts to keep things more stable. That's why it seems to be so much more prevalent in the 2018's.

Yep, and if you read that J&E article about the Gen3 Coyote pistons it sounds like they shortened the piston skirt even more compared to the Gen1 and Gen2 pistons, which combined with the increased bore diameter may not be a good design. If the piston skirt coating is worn down to bare aluminum in a few thousand miles then something is wrong. According to the J&E piston article, their coating is supposed to last for the life of the engine.

http://blog.jepistons.com/jes-patented-perfect-skirt-coating-is-a-breakthrough-in-piston-technology

From the J&E piston skirt coating article link above:
"Perfect Skirt is a solvent-based coating that is permanently applied to the piston skirts in a 3-stage bonding process. Unlike many coatings, it is not a temporary layer for break-in. It will stay bonded to the piston throughout its service life."

 

[Condor1970]

Yep, and if you read that J&E article about the Gen3 Coyote pistons it sounds like they shortened the piston skirt even more compared to the Gen1 and Gen2 pistons.

You right on target. Because they have an even shorter skirt, and the same location of the pin boss, the rocking of the piston can be even more pronounced that the 15-17' engines. I think this is also part of the reasoning for installing 4 knock sensors now, in order to get better feedback for the ECU to control ignition, in an attempt to keep things more stable. The problem is, I think the mechanics of it far outweigh the ECU's ability to prevent slap. Just a very slight knock, and that piston will be tossed to one side, and thrown to the other side from inertia when the crank cycles it around. I thin it's one of the reason SO MANY guys are have Misfire CEL's, because this 4 sensor system, is so sensitive, just the slightest screw up, and everything goes haywire.
To be honest, I think this engine is now designed beyond what it is capable of as a naturally aspirated design. There's only so far you can go, before it exceeds the engines ability to operate reliably for the long term.

The piston skirt coating is great, but nothing is perfect. If there is a slight bit of long term timing issue, or too short a skirt design that allows for constant piston slap like we are hearing, eventually even that coating will get worn off. Even diamond will eventually erode away from running water.

 

[GT Pony]

You right on target. Because they have an even shorter skirt, and the same location of the pin boss, the rocking of the piston can be even more pronounced that the 15-17' engines.

Sounds like they did change the wrist pin location. From the J&E piston design article:

"To best service the Coyote engine platform, JE has developed a dedicated forging that has been specifically designed for these engines and their high horsepower capabilities. It utilizes one of JE's Forged Side Relief forgings, which offers many benefits. Chief among them are the reduced skirt width and a shorter wrist pin, which reduce reciprocating weight without reducing strength.

The narrow skirt reduces piston contact to the cylinder wall to minimize friction, while the pin location is offset toward the major thrust side of the piston to help reduce piston noise, critical for those engines which are run on the street."

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