Letter 1671

Where is the Nikasil supplier?

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I am searching for a supplier of "Nikasil" plating chemistry, specifically interested in finding a solution operable in a "brush" or selective plating environment.

The coating is being widely used in the manufacture of motorcycle engine components (i.e, cylinder bores, pistons, piston rings) and the restoration of engine cylinder bores.

Robin M
- Sears, MI

Nikisil® is a proprietary product of Mahle. If you desire information you should contact Mahle.

Dennis McCallister
Morristown TN

Although Nikisil® is a trademark of Mahle Corporation, our company has engaged in nickel silicon-carbide plating and diamond honing in the United States since the mid 1960s. We are presently one of the largest such companies in the world. We have found that by far the greatest demand for nickel silicon-carbide has been for aluminum cylinder bores, and the market still appears to be growing. We have no method of "brush plating" this coating.

Scott Z. Reath
U.S. Chrome Corporation of Wisconsin - Fond du Lac, WI

My company has been offering a Nickel/Silicon Carbide coating service on aluminum cylinders for many years both here in Alabama and at our original facility in England, and have a throughput of several thousand cylinders each year. Like them too, we are not aware of any brush plating technique that offers good results and a quick survey of our associated companies around the world yields the same response, but I suspect that one could be developed given sufficient demand.

Geoff Slater
Auburn, AL

My electroless nickel reference indicates that Elnisil is a galvanically deposited dispersion coating of carbide, presumably carbide in nickel. Brush plating of this process may be less problematic than Kanisil or Nikasil, although the abrasion resistance is less for Elnisil.

See Metzger, W. et al. galvanotechnik 61 (1970) 12, 998

Tom Pullizzi
finishing.com - Brick, NJ

We need to put up a plant for Ni Sic plating for plating the bore of our new engine. As the Volumes are not very big (around 30,000 engines per year) we are looking for a cost effective solution.

Can we modify an existing electroplating plant for Ni & Cr for this process. Can I set up a pilot plant before mass production. Would be grateful for replies

Kumar R
Jakarta Indonesia

I would like to know whether any one has any experience in coating Nikasil or similar composition on Graphite rods.

Venky C
- Illinois

I am rebuilding a Porsche 911 engine which uses removable cast iron cylinders. Can anyone recommend the most cost effective method for plating the cylinders to restore them to their original dimensions?

Ben M

I am a student in Istanbul Technical University. I am interested in Nikasil and Alusil. Which one of these gives better performance on pistons (especially cars).I study Metallurgical and Materials Engineering and this subject is my final work. Could you please send me any documents about this subject or offer books, magazines etc...

Thank you.

Ozgur O
- Istanbul,TURKEY

Ed. note: letters 551, 2723, and 2858 address a similar topic.

I have a few questions. Can nikisil® cylinders be honed once or twice to clean them up? I've got a very low mileage 4-cycle engine in which the pistons dry-seized to the cylinder wall during long, improper storage. With steel sleeves I'd simply have a machinist perform a very light hone to clean up the cylinders.

How critical is the matching of pistons, rings, and cylinders in nikisil® set-ups? I've got a feeling it is a good thing, but necessarily critical. The question developed because I've seen suppliers selling piston, ring, and nikisil® cylinder sets. Two rings on one of the aforementioned engine are stuck in the grooves and must be replaced for engine reassembly. I would like to clean all parts, hone the cylinders, replace all rings, and reassemble the engine.

Thank you.

Bill S
- Concord, CA

The first thing to be aware of is that the Nikasil layer will probably be very thin, and so you should be prepared for that when considering any machining operation.

Typically, engine manufacturers using Nikasil and similar processes 20 years ago would have deposited a finish-machined thickness of about 0.10 mm (0.004"). More recently, we have noted that cylinders from several Japanese manufacturers have thinner coatings, sometimes as thin as 0.05 mm (0.002"), almost certainly as a result of improvements in the plating technology enabling a reduction in materials and processing times.

In normal use, it should be unnecessary to hone nikasil-type engine cylinders since the wear resistance and oil retention derives almost as much from the presence of the silicon carbide particles in the nickel matrix as from the original underlying honed surface finish. In Bill S's situation, it appears that there are marks on the bore which will need to be removed to avoid damaging new components during a re-build, and so honing will almost certainly be required. It is important that this be carried out using diamond honing tools of an appropriate grade, since the original surface finish can easily be "polished" by using conventional honing stones, and that may lead to a lack of adequate lubrication during the initial running of the engine.

One of the big performance advantages of nikasil-type bore over traditional cast iron sleeves (other than a major weight saving) is the ability to operate an engine with smaller piston to bore clearances since the piston and the cylinder will tend to expand a similar amount when heated. For that reason, it will be important for Bill S to accurately measure the bores after honing, then select pistons which will give him a clearance which satisfies the engine manufacturers specifications. Most normal piston ring materials work well with nikasil-type bores, but chrome faced rings (at least the compression rings) are by far the most commonly supplied by engine manufacturers. Close attention should be paid to the ring-end gap to ensure compliance with manufacturers specs.

Sorry the reply is so long, but I hope it answers Bill S's and some other questions at the same time.

Geoff Slater
Auburn, Alabama

I would like to thank Mr. Geoff Slater of Auburn, AL for the rapid and informative response to my engine rebuilding questions dated June .. In his response, George apologized for making a long reply. Apology accepted, however no apology was necessary. George provided a great bit of information in a very concise manner. Not only did I gain the confidence to rebuild the engine, but I was also provided with useful practical and factual information. Believe me, there are quite a few people claiming to be knowledgeable about engine coating and plating that make it up as they go.

One last item, Geoff. The subject engine has been reassembled and runs like a fine watch. The Italian motorcycle which this engine powers is a 1986 Moto Morini 350K2. This model was one of the last manufactured by Morini before they went out of business. The engine is a V-twin having 70 degree cylinder offset and Heron heads (flat head, combustion chambers in piston).

Thank you.

Bill S
- Concord, CA

I am in the process of building some racing V-6 engines. These engines have a metal matrix composite engine block with Reynolds 390 series alloy as the base metal. The bore is 93 mm.

Alternatively, has anyone ever done this to the pistons instead of the block? My problem on this is that I have had to make forged pistons due to the boost pressures involved with this project so the aluminum on aluminum, won't cut it. I have exhausted all efforts to find a company that can do an iron plating so I have had to go the Nikasil route.

John C
- L.A. CA USA

I've recently seized an engine on a 2000 YZ 125 dirt bike, and I realize this might not be the place to ask, but I only had a few quick questions :O). Since the 80's I believe the big four (Japanese) companies have used a thin Nikasil coating which is supposed to increase cylinder wear...etc...etc... I've been told that due to the thin layer provided, rehoning the cylinder is impossible (Or at least stupid) without having a new Nikasil coating added.

So my question is, if I only plan on having this bike for the next few months, and I've just installed a new piston, rings, crankshaft, and rod, will I be setting myself up for frequent engine failures and bad performance?

If anyone has any information on the costs involved in the process provided, I'd greatly appreciate it, Thanks.

Dean P
- Aurora, Colorado, USA

There seem to be alternatives to Nikasil for the wear resistance improvement of aluminum cylinder bores. I've found companies that specialize in the ceramic coating of engine components; even worn out ones. Their claims seem to imply tremendous advantages. Check out their sites and see what you think. There are also coatings for "lubricity" using graphite and Molybdenum disulfide that are deposited on cylinders and pistons to reduce friction & galling. These are very high temperature coatings which ceramics seem ideally suited to and various process for deposition seem to be well worked out and not expensive. They have been used in racing vehicles for many years. It's a real eye opener what ceramics can do for an engine.

Good luck.

Peter K
Freelance - Kelowna, BC, Canada

Hello

I was looking for information on Nikasil and was pleased to find this page with its useful information.

Although much is said of the benefits of coating cylinder bores with Nikasil, there seems to be very little information available as to what sort of piston ring is best for use with such Nikasil plated bores.

I have been surprised to find that noone can give me a straight answer! I have a 2-stroke engine with Nikasil coated aluminium cylinders. Original piston rings are plain cast iron. My question is, can one safely use chrome plated piston rings with Nikasil bores?

My first thought was that the 2 together should increase longevity however it's been suggested that the chrome rings will simply strip the thin Nikasil layer from the bores and destroy the cylinders.

Could someone who actually knows tell me the answer please?!

Many thanks,

Joe Conrad
engine rebuilding - Halifax, West Yorkshire, England

December 17, 2008 I also have a 2-stroke motorycle motor with nikasil coated cylinders.My problem is that my cylinder wall has a light score in it(just enough to hook your finger nail)where the piston/rings melted and broke apart.my questions are:1.is the nikasil coating scored all the way through so that it can't be repaired?2.can it be honed with a silicon carbine hone in order to repair it myself or should i get it bored and replated at a qualified company?3.what will happen if i remove the nikasil coating and reinstall a new set of piston and rings?4.what will occur if i leave the coating scored and replace the pistons/rings?please take into consideration that I am only young and have a limited amount of income.Thanks in advance to everyone who respond to my questions. Steven Turnip - Newfoundland,Canada December 26, 2008 right to answer Steve Turnip no dont hone it its too thin.if u remove the coating the bore will be oversize and not seal and u will be running on an aluminum base and it will last a very short time (seconds probably). if u leave the bore scored then u will get blow by, low compression, burnt piston/bore as the combustion gases rush by. wont last long! sorry but re plate is the only real answer. now here is a question for u platers can anyone machine and replate the epitroidal housing used in the norton rotary engines. it seems that some engineering processes become impossible. John Hall - Ripon, North Yorkshire, UK