Nicasil plating of (steel) cylinder bores...

[Mary or Stephen Burgess]

Nicasil was a product developed for the British Air-Force by a chemist that
it's my pleasure to know (he's a great friend, and is very good for free
info on all sorts of stuff).

The original use of nicasil plating was for the nosecones of rockets, it has
a very low co-efficient of friction (better than teflon), is very, very
hard, and does not transfer heat well. 

It's curing, and breaking in process is ideal for use in internal combustion
engines, where the hotter and harsher the breakin, the better it performs.

To my understanding, nicasil is used greatly in the cylinders of a lot of
modern motorcycles with aluminium cylinders. 

There are several other coatings, similar to nicasil, used in automotive
applications (steel cylinders), that are experiencing limited success (the
Dodge Neon uses a coating that comes off if the engine is loaded too heavily
while still cold).

I think I recall my friend mentioning that you could get this stuff in two
different states - a pure "A" state that requires a catalist and a cure
temperature of around 3000'C, or a "B" state that does'nt require a catalist
and cure's around 1200'C (guess which one is more expensive). I looked into
doing some steel cylinders with it, but look was as far as I got. I felt it
would insulate the cylinders too well from the water jackets, and the engine
would probably burn up. 







At 09:38 PM 2/4/00 +0100, you wrote:
>Hi
>
>With all this talk of the vega engines I came to think about the technology
>used on dirtbike engines. An aluminum bore plated with nicasil, whatever
>that is, it was many years since I played with bikes. Can that be done to a
>steel bore, I remember that is was supposed to make the heat transfer better
>or maybe that was because of the aluminum bore.
>
>I know that there was almost no wear on the bores, I think that I have the
>25th set of piston and rings or so in my old dirt bike and it has never had
>any work done to the cylinder bore. There is (was?) a place here in sweden
>that could apply a new plating if the bore had to be machined to an over
>dimension. I also remember that some place fitted steel bores in the
>cylinders and if you used that aproach different piston rings had to used
>and all of a sudden you also had cylinder wear.
>
>I had a KTM 4 stroke dirt bike that also had nicasil plating and that bike
>had no measured wear after 20000+ miles. That includes the piston!
>
>Jörgen Karlsson
>Gothenburg, Sweden.
>
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