Another '18 Coyote engine to bite the dust. (Buy back accepted)

[pro 5.0]

Also the liner is .062 thick not exactly paper thin and fyi the PTWA surface is actually harder than a sleeve.

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[HoosierDaddy]

2011 to 2017 had cast iron liners and no scuffing issues, so in you opinion PTWA is better got it.

He said cheaper, not necessarily better. That's why the MSRP dropped so much in 2018 and 19.

 

[pro 5.0]

 

[Condor1970]

2011 to 2017 had cast iron liners and no scuffing issues, so in you opinion PTWA is better got it.

Theoretically, yes it is far better material. It is specifically engineered to be much harder, and has an identical expansion and contraction rate to aluminum. Plus, the material having molecular bond to the aluminum makes it a far superior way to go.

The reason I think they are scuffing more, is because of two things. The pistons have a larger diameter, so I think they may have more tendency to rock and cause piston slap. Especially with the fairly short skirt design they use. Second, because it is a much harder material, the cross-hatching of the cylinder wall will scrape off the coating on the piston skirts easier.
It's also possible the location of the pin boss may not have been relocated to be in the perfect spot to prevent excessive piston slap. This is only a guess though.

It's quite possible the scuffing you are seeing is not the PTWA material getting damaged. Instead, it may be the coating and aluminum from the piston skirts literally getting embedded into the cross-hatching of the cylinder wall.

 

[cosmo]

Stick your head in the engine bay just above the A/C Compressor. Is it louder? If you focus, can you feel it in the shifter? If so, that's the old classic issue that was never fixed as they never changed the position of the A/C Compressor relative to the crank.. Old fix was to add a tensioner to the compressor belt line.

Not a durability issue, just noise.

https://latemodel.cachefly.net/downloads/tsb05-14/tsb12-08-14.pdf

 

[mustangflanagan]

That's interesting I got that same thud sound.. Thought it was knock but I got exactly what u described it as.

 

[GT Pony]

Stick your head in the engine bay just above the A/C Compressor. Is it louder? If you focus, can you feel it in the shifter? If so, that's the old classic issue that was never fixed as they never changed the position of the A/C Compressor relative to the crank.. Old fix was to add a tensioner to the compressor belt line.

Not a durability issue, just noise.

https://latemodel.cachefly.net/downloads/tsb05-14/tsb12-08-14.pdf

That TSB is for 2011-2012 Mustangs. I'd hope by now they would know how to design belt drive systems based on lessons learned from prior TSBs.

 

[cosmo]

That TSB is for 2011-2012 Mustangs. I'd hope by now they would know how to design belt drive systems based on lessons learned from prior TSBs.

Nope. Not sure why. The trucks all get a tensioner which eliminates the noise, but they use a stretchy belt on the A/C Compressors for Mustang. I don't know if it's cost, or weight, or what. But if you go look at your FEAD right now, it's a stretchy belt.

 

[barron64]

I worked at a company that electroplated nickel silicon carbide (nicasil) onto engine bores. We repaired and or plated all kind of aluminum blocks from as small as 50cc single cylinder motorcycle engines to large bore V8 engines. Plated bores be it NiSiC or PTWA, are an advancement over cast iron liners. Better wear characteristics, better heat transfer, More consistent cylinder geometry, tighter piston to cylinder wall clearance, less friction, less weight, and less machining costs are some of the obvious benefits.

 

[GregO]

Nikasil was perfected in the late 60’s
German Engineering, who would’ve guessed .....
Don’t forget the coatings ability to retain lubricant.
Ring streaking will fool some and cause false alarm.
Borescope light intensity will highlight perfectly acceptable scuff marks.

 

[Strokerswild]

I worked at a company that electroplated nickel silicon carbide (nicasil) onto engine bores. We repaired and or plated all kind of aluminum blocks from as small as 50cc single cylinder motorcycle engines to large bore V8 engines. Plated bores be it NiSiC or PTWA, are an advancement over cast iron liners. Better wear characteristics, better heat transfer, More consistent cylinder geometry, tighter piston to cylinder wall clearance, less friction, less weight, and less machining costs are some of the obvious benefits.

Nicasil is great - until it flakes. I've seen nic failure in a few snowmobile cylinders, it gets ugly in a hurry.

 

[CB18]

The first I heard about nicasil cylinders was 1986. Was my KTM 500. Single cylinder two stroke.

 

[barron64]

Nicasil is great - until it flakes. I've seen nic failure in a few snowmobile cylinders, it gets ugly in a hurry.

Yes, I saw plenty of cylinders that flaked but...95%, if not more, were two stroke cylinders. Lots of ports and edges to cause issues. Add this to just a wisp of oil for lubrication, lean jetting and big power for their displacement and you can get flaking. However, if plated properly with good lubrication, proper piston/cylinder wall clearance and reasonable jetting it is a BIG advancement over a cast iron liner. On 4 stroke engines, I rarely ever saw any issues.

 

[Strokerswild]

Yes, I saw plenty of cylinders that flaked but...95%, if not more, were two stroke cylinders. Lots of ports and edges to cause issues. Add this to just a wisp of oil for lubrication, lean jetting and big power for their displacement and you can get flaking. However, if plated properly with good lubrication, proper piston/cylinder wall clearance and reasonable jetting it is a BIG advancement over a cast iron liner. On 4 stroke engines, I rarely ever saw any issues.

Correct, usually 2-strokes are the culprits for all those reasons.

 

[swooshdave]

Chrome flaking: Vintage Moto Guzzis. Pretty common. In theory it should last forever, but something caused it to flake with terminal results. Perhaps it was moisture between the chrome and the aluminum.

Nikasil failures: Jaguar is the most infamous. https://www.popularmechanics.com/cars/a6643/top-automotive-engineering-failures-jaguar-nikasil-v8/

So no matter how good it looks on the engineering paper what really matters is when it's on the road.

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