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topic 3605

Who can do Alusil coating process on aluminum engine blocks?

A discussion started in 1999 but continuing through 2018


RFQ: Certain European engine manufacturers use a coating known as "ALUSIL" for wear resistance in aluminum engine blocks. What is it? Who can perform this process? Thanks.

Greg V [last name deleted for privacy by Editor]
San Antonio, Texas


A. Hi Greg, Alusil is the trademark name of Kolbenschmidt AG in Europe for the process used in their aluminum engine blocks. Alusil basically consists of about 70% aluminum and 30% silicon. Alusil is used to replace Nikasil (a trademark of Mahle) that had corrosion problem with high sulfur content US fuel. Racing Dynamics has the information about Alusil. It is said that Alusil is a patented process. If you need more detailed information, you'd better get the patent.

Good luck.


Ling Hao
- Grand Rapids, Michigan

What is Silitec?

Q. I would like to know what is SILITEC, that some automotive engines producers use for cylinder liners. Where can I find information about this material. Thanks!

Daniel Lopez
- Stuttgart (Germany)

affil. link
"Characterization of Cylinder Liner Surfaces"
from Abe Books



A. This is the best I could find on the Web:

Cylinder sleeves, or liners, in the crankcases of newly designed V6 and V8 engines from Mercedes-Benz AG in Stuttgart, Germany, are made of a special aluminum-silicon alloy that enables piston-ring tension to be reduced by nearly 50 percent. The new low-friction alloy composition also improves heat transfer in the housing, and provides greater stiffness and lower weight for the aluminum blocks.

A new low-friction aluminum-silicon alloy in the cylinder sleeves of Mercedes-Benz production engines reduces piston-ring tension by half.

In addition, the reduction in cylinder distortion (higher dimensional stability) that is possible with this alloy results in less noise and friction; engine-oil consumption and exhaust emissions are thus reduced. Mercedes-Benz is the first automaker to use the innovative Silitec material in production.

Aluminum die-cast engine crankcases are normally fitted with gray cast-iron cylinder sleeves or cylinder barrels with a galvanized nickel coating to avoid high friction from surface pores that form on the cylinder walls produced in conventional die-casting operations. The new liners are manufactured from a hypereutectic aluminum-silicon-copper-magnesium alloy that is spray-compacted while it is cooled in a nitrogen-rich atmosphere, producing billets with an optimal microstructure. The billets are then formed into cylinder liner blanks in an extrusion press.

Finally, the blanks are specially treated in an environmentally friendly process, aqueous exposure. The resulting smooth surface structure improves friction characteristics and cuts the engine's oil consumption and hydrocarbon-emissions levels. The new cylinder-barrel finishing technology, which includes both the material composition and the surface treatment, was developed by Mercedes-Benz with a partner company.

I would try contacting Mercedes-Benz to get more information.

James Totter
James Totter, CEF
- Tallahassee, Florida

Need Alusil Coating and Machining Service


RFQ: I am looking for a shop capable of Alusil coating and machining services. I am in the process of rebuilding a BMW 750iL M70 engine, and will need boring, honing and Alusil services. Please reply with contact information and budgetary numbers for said services. (wide range is fine)

Andrew F [last name deleted for privacy by Editor]
- Atlanta, Georgia, USA
^- Sorry, this RFQ is outdated
     View Current RFQs


Q. Why is it that Nikasil engines in BMWs have a problem with the nickel reacting with the sulfur in fuel? The upper part of the cylinder wall deteriorates and fails leak down test. They have been replacing these engines with ones made from Alusil. Porsche engines use Nikasil in some of there engines and don't seem to have the same problem. Do you know why?

John Ranney
European Auto Tech - Tucson, Arizona


Q. How can one determine if his BMW is equipped with a Nikasil engine? What is the expected life of a Nikasil engine in miles or years? Does BMW stand behind these engines and if so how?

Harry Meister
Retired - Vancouver, Washington


A. The coatings on a Nikasil engine may last for weeks. It depends on what the car is used for. My uncle's '98 328 has done 50000 and apart from using a liter of oil every 50 miles or so its running fine and I don't think there is a problem with it. I asked BMW what can be done with an affected engine and they suggested bouncing it off the rev limiter for up to an hour starting from cold. Only problem this will totally screw the head. Big bills.

david groan, U.K.
monks - london

affil. link
"How to Rebuild & Modify Porsche 911 Engines"
from Abe Books



Q. I am looking for a piston coating solution that will allow me to run forged aluminum pistons in my Alusil block Porsche 928. Only cast aluminum pistons (iron/tin plated) are available. Cast piston strength does not meet my needs. I must have custom forged aluminum pistons manufactured for this application.

Solution must be durable (current cast aluminum pistons with iron/tin plating typically last several hundred thousand miles of service with proper engine maintenance).

Does anyone know of a ceramic coating solution, if so, where I can purchase it?

(I understand that the iron/tin plating process is not appropriate with forged aluminum pistons.)

Daniel P [last name deleted for privacy by Editor]
- Buckland, Surrey, UK
^- Sorry, this RFQ is outdated
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Q. I'm curious to see what ceramic options are available. But correct me if I'm wrong but doesn't the 944 turbo utilize forged pistons with the factory "Tin" coating?

Mark Whitesell
- Hillsboro, Oregon, USA

March 29, 2013

Q. I have a BMW 540 I 1996 M62 engine, Chassis BU80280. Can you tell me if I have the Alusil or the Nikasil engine block? Thanks.

Alfredo Jimenez
personal - San Jose, Costa Rica

March 24, 2015

Q. Can I use the titanium sleeve for my single cylinder two stroke engine block (yamaha rx 100) to restore my engine for better power and fuel economy, or suggest me for any other material

shaikh zakir hussain
personal user - vadodara,gujarat, india

March 2015

A. Hi Shaikh Zakir. I'm not familiar with the subject. I've only heard of aluminum and cast iron sleeves. But I believe sleeves are available for RX 100's. Good luck.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

March 26, 2015

Q. Thanks ted but at least can you suggest the aluminium grade or its metallurgy which I should use (local sleeves are available in my city but it's not too effective in performance). I heard about silicon aluminium sleeves

shaikh zakir hussain [returning]
personal user - vadodara,gujarat, india

sidebar2 April 22, 2018

Q. I need compositions of Alusil and Alcosta. I have doubt of these two material compositions. I need a brief explanation about the composition of these materials because we want to implement the Alusil instead of Alcosta for diesel tanks. Kindly give me answer please.

Kannan ramar
Madras radiators and pressings ltd. - Gummidipoondi, chennai, india

April 2018

A. Hi Kannan. Alcosta is an ASTM A463 [affil. link to spec at Techstreet] hot-dip aluminum coating typically used for exhaust systems. Posco seems to offer fairly detailed information about Alcosta at and


Alusil is not a coating; it is a solid aluminum & silicon material used for engine blocks and cylinder liners which can be machined to expose the silicon particles for low friction.

For your steel fuel tank coatings you may find this presentation interesting =>


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

December 23, 2018

Q. Wouldn't an electroless nickel coating, especially one that is combined with PTFE, achieve the same objective?

Chas King
DIY enthusiast and once upon a time Metallurgist. - Port Edward, KwaZulu Natal, South Africa.

December 2018

A. Hi Chas. Electroless nickel with silicon carbide (Nikisil) has been widely used in cylinder coatings but I don't think plain electroless nickel, or EN infused with teflon is workable ... but I too would be happy to disabused of my error :-)


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading


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