nicralised

[arielscott]

Does anyone know what the Scott nicralised reg mark on a cylinder means? The cylinder is alloy and the bore looks like chrome plating. It is from a cyc-auto.

[BRIAN MARSHALL]

In the 1930s wear-resistant cylinder coatings were usually chromium carbide, but the trade name you mention seems to be more modern, which is a bit odd. The name is a contraction of Nickel-Chromium-Aluminium-Yttrium, the chemical symbols for those elements being Ni Cr Al Y, so you can see how the name was constructed….
Brian

[Stan Thomas]

It refers to nickasil – a process used to apply a hard chrome deposit on aluminium cylinder bores – much favoured and developed by Moto Guzzi – and which provides for closer running clearances given the pistons and cylinder are similar material.

[James]

@Stan Thomas wrote:

It refers to nickasil – a process used to apply a hard chrome deposit on aluminium cylinder bores – much favoured and developed by Moto Guzzi – and which provides for closer running clearances given the pistons and cylinder are similar material.

Not chrome…. it has among other things nickel

[BRIAN MARSHALL]

Nikasil is a nickel-silicon-carbide coating, and much later than the stuff used on the Scott CycAuto in the 1930s ! From memory Nikasil first appeared in bike engines in the 1960s, notably in the NSU Quickly moped engine, and adopted by many engine makers in later years. It has now been rejected by most firms because it is badly affected by fuels with a high sulphur content. It was officially introduced ‘big-time’ by the German company Mahle in 1967.
Brian

[charlie weeks]

Back in the Nineties I was a buyer for Ford and had to buy a Nikasil facility on behalf of Jaguar for Ford’s Bridgend engine plant. Mahle own the patent and so we had to buy the plant, chemicals and know-how from them. Also, Ford/ Jaguar had to pay a royalty on each cylinder plated. That, plus the cost of the chemicals turned out to be a nice little earner for Mahle who also sold their pistons to Jaguar.

Ford also looked around at other types of engine including the Wankel and I got prototypes Nikasiled at Bristol Aero Jigs who, I believe, also did them for Norton.

Happy days

Charlie

[gammakeith]

My 2001 Ducati has Nikasil coated bores and I’m pretty sure the modern ones still use it. Despite using huge (massively over square) pistons with minimal skirts, bore wear is not common and the big twins can rack up 50k + miles without needing a rebuild. I’ve no idea if that is due to the Nikasil or just good design/materials….

Keith

[arielscott]

Thnk you for the replies. The logo is stamped on the exhaust flange of a Scott cyc-auto cylinder. Scott nicralised reg- in a diamond. The bike is 1938 but I think the cylinder is later but cannot be later than early 1950s. Another first for Scott? I will post a photo when I have worked out how.

[BRIAN MARSHALL]

Following an interesting conversation today with Dave Brierley I have done some internet surfing, and found info about cylinder bore treatments carried out by Laystall Engineering, which used to be run by Scott enthusiast the late Jack Tanner.

They still offer two different processes:- CROMARD, which as the name suggests, is a traditional hard chrome plating.

LAYCARB, which is a silicon carbide impregnation technique, and not an electroplated process.

There isn’t a lot of technical information on their website, but it is worth a look.
Brian

[djcb]

I had a couple of sets of barrels done gratis by Jack back in the 80s and am still running them.

My understanding of the process is that the honing blocks are made in hard leather or similar and the honing fluid has silicone nitride particles in it and the action of the leather blocks forces the SN particles into the cast iron bore and creates a non wearing surface. some suggest that this is at the expense of ring wear but that has not been my experience.

[Author]

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