Nissan 370Z Forum - View Single Post - Dirty gritty drained oil when I did the oil change today

dlmartin81 · 03-13-2010, 11:34 PM

Found this......I know it's talking about aviation engines but probably the same.

AeroShell 100 Plus - Shell Aviation

"Metals such as Copper are normally a problem for oils as they cause oil to degrade quicker than they would otherwise. This can be a problem as many General Aviation engines contain Copper - the largest area is normally found on cam shafts which is left over from the manufacturing process.

When cams are manufactured the cam face is often hardened using a process called Nitriding. This leaves a hard, but brittle, surface - ideal for the cam face, but not for the rest of the shaft. The rest of the shaft does not need to be hardened and it performs better if the surface is not brittle from the Nitriding process. So to protect the rest of the shaft, a thin layer of Copper plating is used to cover all the areas which do not need to be hardened. Once the cam has been manufactured this Copper serves no useful purpose, but it is not removed. This can be a problem for the oil in an engine because, as I have mentioned, the copper acts as a catalyst to make the oil degrade faster than normal - and a degraded oil does not make a good lubricant."

03-13-2010, 11:34 PM	#61 (permalink)
dlmartin81 Track Member Join Date: Dec 2008 Location: Chalfont, PA Age: 43 Posts: 923 Drives: 09 370Z Rep Power: 607	Found this......I know it's talking about aviation engines but probably the same. AeroShell 100 Plus - Shell Aviation "Metals such as Copper are normally a problem for oils as they cause oil to degrade quicker than they would otherwise. This can be a problem as many General Aviation engines contain Copper - the largest area is normally found on cam shafts which is left over from the manufacturing process. When cams are manufactured the cam face is often hardened using a process called Nitriding. This leaves a hard, but brittle, surface - ideal for the cam face, but not for the rest of the shaft. The rest of the shaft does not need to be hardened and it performs better if the surface is not brittle from the Nitriding process. So to protect the rest of the shaft, a thin layer of Copper plating is used to cover all the areas which do not need to be hardened. Once the cam has been manufactured this Copper serves no useful purpose, but it is not removed. This can be a problem for the oil in an engine because, as I have mentioned, the copper acts as a catalyst to make the oil degrade faster than normal - and a degraded oil does not make a good lubricant."