Spiny-lok cylinder liner 1

[WilliamH]

Can anyone provide me with just exactly what Spiny-lok casting is? I believe Harley-Davidson introduced this "casting technique" with the Twin Cam 88 as a cylinder wall material.

Whatever information anyone can provide would be helpful (alloy, benefits, etc.).

William H

 

[Azmio]

William

If I am not mistaken, this 'spiny lok' is some sort of structure surrounding the liner. If you look from outside the liner, it looks like the liner has thread. In reality this 'thread' do not spiral upward or downward.

During casting, the 'spiny' will interlock with aluminum to ensure better contact if compared to liner without any 'spiny'. It is also very important as the molten aluminum solidifies as the 'spiny' and the aluminum will be in stress and holds together tightly.

The 'spiny' also works by increasing the surface area in contact between the aluminum and the cast iron liner. The maximum surface area in contact will also ensure that the heat transfer from the bore surface to the outside of the liner and to the aluminum will be maximized.

I have seen liner that has vertical grooves, rough surface (looks like it has just been grit blasted), etc. There are many type of liners available. The idea of using this 'spiny lok' is not new as it has been around in various Japanese and European cars.

 

[WilliamH]

Azmio,

Thanks for the reply. I thought this technique was something in the order of what you described but was not sure.

William H

 

[flowmaster]

The spiny lock system has been replaced by a rough bumby iron surface on the twin cams . i beleive that the spiny lock introduced some cylinder distorsion to the evo cylinder you could always see a shiny track where the cylinder studs were located sugesting that these areas were protruding @ some point .the way the cylinder was constructed having a short spine or no spine @ the location of the stud whole sugested that while the cylinder was expanding and cotracting that the force on these outer spines were actuly bending the liner in @ this location .