plated cylinder liners and sulphur

[alex_at]

many years ago - when high sulphur gasoline was still around - Nikasil plated cylidners hat liner issues due to the high sulphur content in the gasoline not working well with plating.

Nowadays - at least in europe - there isn't really high sulphur gasoline anymore.

But what about high sulphur engine oils - HDEO's for example with up to 1.5% sulphated ash content?

Wouldn't that sulphur content attack the cylinder liners?

I have 2 motorcycles, both have plated cylinder walls. 1 Suzuki C50 which uses Suzukis SCEM and 1 peugeot, which is a "low friction" engine (I guess the liners are plated with a alusil / nikasil coating).

 

[kschachn]

Well first off the "sulfated ash test" doesn't measure the amount of sulfur in the oil, nor does it directly relate to that sulfur content. The test ignites the organic substance (oil) in the presence of sulfuric acid and then measures the remaining ash. It is used to measure the amount of metallic materials in the oil.

As to whether the sulfur in oil affected Nikasil, who knows. Perhaps it did, but the constant combustion of high sulfur fuel (as opposed to the much smaller amount of oil) was what reacted with the coating (not a plating) and eventually caused low compression. Lots and lots of fuel is combusted over time and not so much oil. Besides, the fuel never went to 0% sulfur. Apparently Nikasil could tolerate some sulfur. I know of a friend that had a Nikasil BMW that somehow wasn't driven much prior to the levels being dropped here in the US. He scrapped the thing a year or two ago but not due to the engine. Like my old 530i the rust finally got it.

If your engine is Alusil then it is not a concern. FWIW Alusil is not a coating like Nikasil and your engines are linerless, correct? You don't build engines with Nikasil or Alusil "liners", that's the whole point of using those technologies.

 

[alex_at]

thanks for the explanation kschachn,

yes both engines are indeed full aluminum built - and are linerless.

I have no clue about the coating on the Peugeot, for the Suzuki C50 at least I know its Suzuki's SCEM technology.

 

[benjy]

linerless motorcycle engines have been around a LONG time + is even used in larger automotive applications if cost is not an issue. its a superior system though more costly being why cheaply built harleys still use typical liners!!

 

[ragtoplvr]

alusil Aluminum Silicon? Like the infamous Vega engine. like all the lawnmowers that lasted 3 to 5 seasons.

That Alusil?

Rod

 

[alex_at]

Originally Posted by ragtoplvr
alusil Aluminum Silicon? Like the infamous Vega engine. like all the lawnmowers that lasted 3 to 5 seasons.

That Alusil?

Rod


I have no clue - that's why I can only guess

 

[kschachn]

This looks like a good overview:

https://www.electrosil.com.au/pdf/ElectrosilNikasil.pdf

 

[kschachn]

Originally Posted by ragtoplvr
alusil Aluminum Silicon? Like the infamous Vega engine. like all the lawnmowers that lasted 3 to 5 seasons.

That Alusil?

Rod

Who knows what is used on a lawnmower, but the A-390 alloy in the Vega engine was not the problem. It was poorly designed in other areas especially cooling. Overheating killed those engines not the block alloy nor that technology.

 

[alex_at]

Originally Posted by kschachn
This looks like a good overview:

https://www.electrosil.com.au/pdf/ElectrosilNikasil.pdf


thank you for that

 

[barryh]

BMW motorcycles first used plated cylinders in 1981 and I've heard of very few problems. They also never seem to wear out.

 

[alex_at]

I got some updates: According to the customer service department, which asked the technical department: The cylinder uses a nicel-silicium-carbide plating.

So according to what I've learned in this thread: Oil isn't an issue, the nickel-silicium-carbide coating is very durable. High sulfur fuel isn't available at the pump here anyways. But I will stay away from TC-W3 2stroke oil as an additive for lubrication and cleaning. No need to introduce any more sulphur to the fuel.