Nikasil vs. chrome

[robfromaz1977]

New around here and was curious what makes a better cylinder coating, nikasil or crome? I see some replacement cylinders as having nikasil and wasn't sure if they would last as long as chrome. Thanks.

 

[7sleeper]

opcorn:

7

 

[CanadianCarGuy]

I have gotten some cylinders overbored and rechromed from Kustom Kraft in Colorado. They are nikisil and probably twice as hard factory chrome. But it will flake a little if you are too aggressive with your porting rasp if it is a little dull. A

PS: I have seized up the same overbored 394 cylinder twice, and both times pooched the piston, but didn't even mark up the chrome!! Also if you are planning on turning a closed transfer into an open transfer, wait till the rechrome is done, because the hone will snag on some kinds of open transfers and the guy won't take a chance on it.

 

[Arrowhead]

I have heard chrome was better, but not sure.

 

[demographic]

Its not nickel though is it, its nickel silicon carbide which is a totally different kettle of fish.

Used in motocrossers for years on end.

 

[tdi-rick]

Mahle originally developed Nikasil as a superior coating to the hard chrome available at the time.
IIRC it was originally used in the twin turbo Porsche 917 sports cars that dominated long distance racing in the late sixties/early seventies.
It's still used in racing engines worldwide.

A Stihl dealer on another board claimed that he'd been told by Stihl and Mahle that hard chrome was a superior process, but all I know is that most all aluminium race blocks are still Nikasil or derivatives, as are Porsche road engines, or at least were until the last ten years.

There used to be a history of the coatings on the Mahle site. I'll see if i can dig it up.

 

[WalterWhite]

Mahle originally developed Nikasil as a superior coating to the hard chrome available at the time.
IIRC it was originally used in the twin turbo Porsche 917 sports cars that dominated long distance racing in the late sixties/early seventies.
It's still used in racing engines worldwide.

Nikasil has also been used for years in BMW motorcycle air cooled engines. (I'm not sure if it was used in the water cooled ones too.) There is some information at this site: http://bmwmotorcycletech.info/cylinders.htm

 

[Cantdog]

Nikasil

Yup, as tdi said most race based engines are nikasil.

Ducati Supersports and Superbikes as well as Jonsereds.

Red and nikasil all the way!!!

 

[tdi-rick]

Done some more reading and Porsche still use Mahle Nikasil on their aluminium blocks.
All the F1 engine blocks coated by Mahle currently use Nikasil. This includes Ferrari, BMW, Mercedes-Illmor, Renault.
The Audi V12 TDI engines used in the Le Mans car uses Nikasil coated bores.

Nikasil is a lower friction surface than chrome or cast iron, with better oil retention. It's described as oleophilic.

"NIKASIL®-coated cylinder crankcase
MAHLE trademark for a protective surface coating for engine components, particularly cylinder liners. It improves the tribological properties of the cylinder bore and the interaction between cylinder liner and piston."

Apparently there used to be a problem with high sulphur fuels and Nikasil in four strokes, but with modern fuels this isn't an issue anymore.