Break down of different engine bore coatings.

[Mainia]

When people were talking about engine bore coating I always knew there were multiple kinds used. Here is a breakdown of the different types and why they use this form of cylinder material vs not using just good old cast iron instead.


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[demarpaint]

Weight saving, cost saving. Call me old fashion I'd rather have a cast iron cylinder/liner.

 

[Cujet]

A good video, but he fails to mention that Nikasil can be applied to just about any of those 'non rebuildable' cylinder liners. Alusil for example simply needs to be bored oversized to remove the etch-created layer, and coated with Nikasil. Same goes for the iron thermal spray. Bore out the iron, plate the bore with Nikasil.

Nikasil will likely require different rings, and maybe different piston coatings. But the advantage is 3x the bore life of the best cast iron bores. NiCom, a process I've used extensively, is very similar, and is said to be 5x better than compacted graphite cast iron bores. It is great for non engine use too. Such as off road shock damper bores.

Note: some of these Nikasil alternatives (there are many, and they vary in quality and composition a bit) can actually be applied with brush plating. It's just like it sounds, a brush dipped in solution is electrified and brushed against the surface, where transfer plating takes place. Generally not as robust, but pretty darn good.

Aircraft cylinders are typically made of steel, can be coated with NiCom or Nickel Carbide coatings. This prevents the common rusting problems and virtually stops wear related issues. Although some users have had the coating flake off, I don't think this is a frequent occurrence.

 

[Marcozi]

Nikasil is what BMW used in some of it's V8 engines. Due to gasoline's high sulphur content at that time, BMW had to replace a bunch of engine.

 

[Cujet]

Nikasil is what BMW used in some of it's V8 engines. Due to gasoline's high sulphur content at that time, BMW had to replace a bunch of engine.

My F-Type Jaguar AJ-126 supercharged V6 engine also has Nikasil bores. They are not known to fail. But I'm fairly sure today's fuels are very low sulfur.

 

[Kruse]

Decades ago, the Chevy Vega was getting a real bad rap for their linerless aluminum-silicon block.
I remember that just about every man's magazine out there had advertisements for re-sleeved Vega blocks.
My cousin had one at that time. IIRC, the GM warranty on the engine was good until 36K miles. Whatever it was, I remember my uncle driving it to the dealership to get a brand new engine....with about 20 miles to spare.

 

[loneryder]

Mercedes nanoslide coating. They have to hone the mirror like finish so oil will stick to it.

 

[97prizm]

A good video, but he fails to mention that Nikasil can be applied to just about any of those 'non rebuildable' cylinder liners. Alusil for example simply needs to be bored oversized to remove the etch-created layer, and coated with Nikasil. Same goes for the iron thermal spray. Bore out the iron, plate the bore with Nikasil.

Nikasil will likely require different rings, and maybe different piston coatings. But the advantage is 3x the bore life of the best cast iron bores. NiCom, a process I've used extensively, is very similar, and is said to be 5x better than compacted graphite cast iron bores. It is great for non engine use too. Such as off road shock damper bores.

Note: some of these Nikasil alternatives (there are many, and they vary in quality and composition a bit) can actually be applied with brush plating. It's just like it sounds, a brush dipped in solution is electrified and brushed against the surface, where transfer plating takes place. Generally not as robust, but pretty darn good.

Aircraft cylinders are typically made of steel, can be coated with NiCom or Nickel Carbide coatings. This prevents the common rusting problems and virtually stops wear related issues. Although some users have had the coating flake off, I don't think this is a frequent occurrence.

Would Iconel or a graphite coating work?

 

[Exhaustgases]

. But the advantage is 3x the bore life of the best cast iron bores.

This caught my eye.
I don't think there is any manufacture that wants anything lasting 3 times longer.

And besides nothing else in any of these modern day automotive engines will need bores lasting 3 X longer, especially with wet belts, timing chains and all the other internal plastics.

 

[Cujet]

Would Iconel or a graphite coating work?

As I understand it, inconel can be, and is used, as a cylinder bore material in very high heat situations. Such as high temp air flow valves. Whether it could be made into a sleeve that could be pressed in to a conventional engine is another matter. A conventional graphite coating would probably be a short life option. As to whether a DLC coating would work, I suspect yes with the proper engineering behind it

 

[Hohn]

DLC could work, but how are you getting a crosshatch honed into the DLC? You can’t DLC over the finish honed bore, it ruins the geometry and surface finish.