Cylinder walls?

[erhayes]

I have never been able to find out what kind of cylinder walls the SkyActiv engine has. Some manufactures use a high silicon content, some use iron sleeves but, I could not find anything about our CX5.. Does anyone have information in that area? Just curious Ed

 

[Anchorman]

Ive got these on the 2.0 engine which carries across I believe.

 

[erhayes]

Thanks Anchorman. Ed

 

[yrwei52]

Since the cylinder block is made of aluminum alloy, cast iron cylinder liners has to be used for cylinder walls. Chevrolet Vega had tried using aluminum block without iron sleeve for cylinders and failed miserably.

 

[MikeM.]

Since the cylinder block is made of aluminum alloy, cast iron cylinder liners has to be used for cylinder walls.

Not true at all. There are a number of different solutions that are durable and don't require iron sleeves.

My '85 Ducati has aluminum cylinders with an electroplated hard coating called Nikasil, short for Nickel, Silicon Carbide. It is more durable than iron liners and offers much better thermal conductivity than iron. It has been used by Audi, BMW, Jaguar, Ferrari and other high performance engine makers. It's primary weakness is it's incompatibility with low quality gasoline containing high sulfur content. Nikasil lined cylinders allow the engine to be lighter, more durable and resist detonation better due to it's superior heat transfer.

When re-boring a cylinder it is necessary to re-apply the nikasil coating, an extra step that is somewhat expensive.

 

[erhayes]

My early year Porsche air cooled engines used a chrome plated aluminum cylinder. Later years they used a close grain, high carbon cast iron. Not sure what is the latest but, I would expect the NIKASIL treatment. I wasn't aware that re-boring was an option with these blocks Mike. Ed

 

[Kedis82ZE8]

Another coating material is molybdenum

 

[yrwei52]

Since the cylinder block is made of aluminum alloy, cast iron cylinder liners has to be used for cylinder walls. Chevrolet Vega had tried using aluminum block without iron sleeve for cylinders and failed miserably.

My statement should be "Since the cylinder block is made of aluminum alloy, cast iron cylinder liners has to be used for cylinder walls with reasonable cost and longevity for a mass production automobile."

Still, there is no definite answer for OP's question. But I stand corrected on my guess.

 

[GAXIBM]

I think my 2000 Corvette LS1 uses steel sleeves with the aluminum block.

 

[tibimakai]

Jaguar had a bunch of issues(in 2000 with the V8 engines), with the Nikasil coating.