ALUSIL vs NIKASIL CYLINDERS

There are several types of plating that have been used over the years. Plating was generally only a few thousands of an inch thick. In the early seventies Electrofusion became popular. Next came ceramic composites and Boron and then came the product Nikasil. Nikasil was the new plating formula of nickel-silicon-carbide for the eighties and later nineties. Today you can choose from companies around the world doing 'their own' version of Nikasil. In South Africa there is probably only one company that can assist with the process at more than twice the cost of any other other replacement piston sleeve processes on the market today.

Nikasil sleeve coatings have been lost within 5000 km use with the wrong viscosity oil. The drained oil looked like aluminum paint. Special rings are needed so the nikasil coating is not scraped off like thin ice on a window and more than ever you must have 100% faith in the underlying process of the Nikasil company that you are dealing with.  

Compared to the trusted and proven re-sleeving process, that now is backed by exciting and well proven products and honing techniques, a new product was developed by Kolbenschmidt and BMW and the alloy composite 'Alusil' was born. Alusil is hypereutectic aluminium-slicon alloy. Alusil is not a coating process but a treatment of the aluminium surface through a honing and lapping process and chemical etching that exposes an extremely hard silicon precipitate namely ‘silica’, thus rendering  the abundant silicon particles on the aluminum surface that act as a well suited wear layer for most engine types as used by BMW, Porsche and many other vehicle and motorcycle manufacturers and engineers today as a first choice of sleeve material. So how reliable is cylinder plating?

Re-Plated NIKASIL Cylinders

Pros

• Only small advantage in heat transfer
• Somewhat lower co-efficient of friction
• Weighs only a few ounces less

Cons

• Costs twice the price of any other process
• Cannot be bored when damaged
• Sulfur in fuel corodes Nikasil plating
• Can crack, flake and peel off
• More fragile than other sleeve materials
• No Guarantees

 Re-Sleeved Cylinders and ALUSIL

Pros

• Costs half the price of Nikasil plating
• Cast iron, Chrome Molly, Alusil can be used
• Alusil has excellent lubricating qualities
• Alusil is light weight and wears well
• All can be re-bored to next oversize
• Honing keep bores true and seals rings
• Can be worked with common tools
• Easily replaced as necessarry
• Guaranteed

 Cons

• Slightly slower heat transfer

Is Nikasil a dying process with the negatives outweighing the positives? By the year 2000 improved materials and new cylinder techniques had become readily available. These new age materials that have been developed and introduced into motor engineering circles have been been put to the test over the last decade or so through the ‘trial and error’ method of elimination over time and has shown Nikasil to be an inferior material for engine sleeves.

In 1997 BMW stopped all Nikasil engine block production and introduced the much desired new all-in-one sand cast Alusil engine blocks and sleeves that have been in production since. Nikasil was replaced for exactly the reasons as set out above.

For more information  CLICK HERE “Engine / Nikasil / Specialist Engineering”  or Call Centre : 0861 7777 22