Sliconizing engine block

[DavidSoine]

Another view of Nikasil...seems that it was only the BMW auto engines that experienced failure...and those are the only ones they have changed to another process - motorcycle engines are still Nikasil as far as I know, and have been working great over the years.

http://www.lnengineering.com/nickies.html

best,

Dave

[Kebowers]

the aluminum alloy block for a MBZ engine is an alloy developed by Reynolds Aluminum. During manufacture, the 'casting' process is carefully controlled so the material closest to the surface of the cylinder bore is richer in silicon--an extremely hard and wear resistant material. The final step is etching away some of the aluminum to leave a 'porus' surface on a microscopic scale. This provides a near perfect surface for a piston ring to work against. It holds oil well and essentially doesn't wear. For a 'field repair' , what one does is use a felt honeing pad with the special silicon honing fluid (from MBZ pereferable) to clean up the surface IF REQUIRED.
Unless there has been actual piston metal transfer to the bore--nothing is need. A dull matt grey finish is 'new' , Carbon or varnish depositc can and should be removed with liquid solvents and a soft cloth. Any scuffing that you can feel with a fingernail calls for reboring to oversize. If the roughness is metal deposit ON the bore, it can be honed away and re-etched. Use only OEM pistons as they have a thin cast iron surface to provide much improved anti-scuff performance over plain aluminum