Nikasil - when parked up

I am looking at buying (another!!!) bike that has Nikasil (or equivalent) bores.
The bike has very little mileage over about 8 years.
Should I be concerned about deterioration of the bore plating?
Cheers

robs ss said:

I am looking at buying (another!!!) bike that has Nikasil (or equivalent) bores.
The bike has very little mileage over about 8 years.
Should I be concerned about deterioration of the bore plating?
Cheers

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Not especially susceptible to rust, any more than iron.

Not like chrome.

concours said:

Not especially susceptible to rust, any more than iron.

Not like chrome.

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But... Nikasil is chrome.

robs ss said:

But... Nikasil is chrome.

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You're right.

I have nothing further.

robs ss said:

But... Nikasil is chrome.

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Say what? It's a nickel-silicon-carbide plating/coating. No chromium involved. More specifically, it's "a trademarked electrodeposited lipophilic nickel matrix silicon carbide coating for engine components, mainly piston engine cylinder liners". Whereas "Chrome plating is a technique of electroplating a thin layer of chromium onto a metal object. A chrome plated part is called chrome, or is said to have been chromed. The chromium layer can be decorative, provide corrosion resistance, facilitate cleaning, or increase surface hardness."

Ken

The ref to chrome is from the earlier generation plated bores which were chrome plated, nikasil has no chrome and is plated onto aluminium alloy anyway.


The BSA B44 Grand Prix was an early example of a hard chrome plated bore.

kommando said:

The ref to chrome is from the earlier generation plated bores which were chrome plated, nikasil has no chrome and is plated onto aluminium alloy anyway.

Norton Twins Aluminium Barrels

Norton Twins Aluminium Barrels for Commando Dominator Cafe Racer

www.tga.co.uk

The BSA B44 Grand Prix was an early example of a hard chrome plated bore.

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As were early 700/750/850 Moto Guzzi twins from the late 1960's to the mid ish 1970's .
Most likely moisture (perhaps from sitting for long periods) did not help and having no oil filter the chromium would cause all manner of havoc.



The line where the top ring reached TDC is actually a wear groove in the alloy of the cylinder casting.
Besides fitting Gilardoni 88 mm cylinders (948cc) which are modern Nikasil replacements that look externally the same as the originals, every component in the oiling system was replaced or refurbished due to damage, I also machined the engine case to use the later model oil filter pan.

Nikasil should be fine sitting, most likely it would be moisture that might compromise it long term if there was a problem being only as good at the bond to the alloy of the cylinder bore.

One of my TL's has sat in storage since October 2007,



I have spare new parts should the worst be found when it and the others are reinstated to running condition.
It will need the engine out, but a borescope inspection would most likely show obvious damage at the location where the pistons and rings have been sitting for coming up 17 years.

lcrken said:

Say what? It's a nickel-silicon-carbide plating/coating. No chromium involved. More specifically, it's "a trademarked electrodeposited lipophilic nickel matrix silicon carbide coating for engine components, mainly piston engine cylinder liners". Whereas "Chrome plating is a technique of electroplating a thin layer of chromium onto a metal object. A chrome plated part is called chrome, or is said to have been chromed. The chromium layer can be decorative, provide corrosion resistance, facilitate cleaning, or increase surface hardness."

Ken

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Theoretically you shold not be able to electroplate chromium on steel. Normally when you electroplate, the anode is sacrificed and the plating occurs on the cathode. With chromium, plating begins with reverse potential which causes an oxide anode slime to occur on the part to be plated. Then the current is suddenly reversed, and an over-potential situation occurs which enables the 'strike'. With chromium, if the current is interrupted, double-coating can occur and the second coat will not adhere.
Plating on unalloyed steel is no problem, but the formation of the anode slime to get the strike is important - alloy steel and aluminium present more risk
Nickel plating is the worst for double-coating.

Chromium is good as a wear surface where no impact occurs. One of the highlights of my career was firing a 5 inch naval gun out into Spencer's Gulf in South Australia. We had chromium plated it's bore. Some things really make me laugh. I know why men like playing at being soldiers. I had the best jobs anyone could ever want.

Nikasil coating might not be a plating process - but a metal spray. I did know something about it 30 years ago.

acotrel said:

Nikasil coating might not be a plating process - but a metal spray. I did know something about it 30 years ago.

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Nikasil is an electroplating process. Silicon carbide is dissolved in nickel, and the resulting solution is electroplated onto the aluminum bore, then finish honed. There are other similar proprietary electroplating processes that utilize dissolved ceramics in a metallic matrix.

More history and info here:


Ken

Regarding OP, is there a make/model/yr bike involved here? might narrow down the coating ..

74ok said:

Regarding OP, is there a make/model/yr bike involved here? might narrow down the coating ..

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No - I was looking at an older engine rebuilt with plated liner (Nikasil or similar) and was concerned about potential for the coating lifting away.
Spun liners aren't as good friction and wear wise but don't lift.
The comments have been helpful - thanks

For anyone interested in more info on NSC plating, Milleniium is a popular US provider of nickel siliicon carbide plating of aluminum cylinders. Their site has some good tech videos about the technology.


Ken

lcrken said:

Say what? It's a nickel-silicon-carbide plating/coating. No chromium involved. More specifically, it's "a trademarked electrodeposited lipophilic nickel matrix silicon carbide coating for engine components, mainly piston engine cylinder liners". Whereas "Chrome plating is a technique of electroplating a thin layer of chromium onto a metal object. A chrome plated part is called chrome, or is said to have been chromed. The chromium layer can be decorative, provide corrosion resistance, facilitate cleaning, or increase surface hardness."

Ken

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I have been aware of how this process is utilized but never could I explain it with that kind of clarity...thanks.
Yet another reason I enjoy this site and pay to play here.