Does anyone here have experience with Nickel Silicon Carbide Coatings used in cylinders instead of cast iron liners? Shed some light on this. I was reading that it has been in widespread use by many companies including Porsche. Is this true?

 

it is true that porsche has used this for many years because it is not as subject to heat and as you know up until just a few years ago all 911 porsches were air cooled and subject to high heat. i dont know of anyone using them on motorcycles although it would seem to be a good idea.

 

Actually there are members of this forum that use them. There is also a forum sponsor that manufactures them, Rev Performance. The 98" kits they sell are Nickasil coated.

 

RevPerf's Jugs are absolutely flawless and the Nikisel (sp) stands up to some serious torture....

They even stood up and replaced a jug that the coating was discolored from the sleeve...

We have used their products on our HiPo builds with great success, and our drag bikes with even better success (Race on Sunday, sell it on Monday)....

And their 124 jugs are the ultimate in "Sleeperwear".....

 

THATS GOOD TO KNOW. ESPECIALLY FOR A CUSTOM BUILD.

 

Hey Guys,

I posted this on another forum. I think it might help a bit. Also, check out the video on the front page of our site at www.revperf.com

Hey guys,

I will basically bring some facts to light and then you guys can give us a call to discuss it further if you would like.

1. The RP cylinders are a high silicon content, aerospace grade cast aluminum alloy with nickel-silicon-carbide plated bores. Feel free to go to revperf.com and download the video on the front page for the process. Contrary to the competition’s argument they are in fact torque plate honed as is evident in the video. This equates to a cylinder that is very stable and allows piston to sidewall tolerances in the neighborhood of .0012-.0015 even on the 4.250" bore motors. The MoCo is just about the last major manufacturer on the planet that is still holding on to the cast iron lined cylinder. Victory, Yamaha, Honda, Suzuki and Kawasaki cruisers, all 4 stroke single dirt bikes, and inline fours all have aluminum cylinders with plated bores. Every other manufacturer on the planet of substance can't have it wrong. Some are air cooled and some are water cooled but the premise of compatibility and long life remains the same.


2. The cylinders do shed a tremendous amount of heat comparable to a cast iron sleeved cylinders. It's pretty much physics 101. All aluminum construction cools quicker that cast iron. Now, with that said, cast iron does have it's place in high stress situations and should not be discounted. Does every application run 40 degrees cooler? That would be a stretch to say because every combination is different. The physics of the material don't change though and I assure you that all aluminum will shed more heat.

3. The question was raised about boring. You never have to bore the cylinder again. Let's take the RP warranty out of the equation and concentrate only on, say, a Victory cylinder. If that cylinder ever wears out (not likely by the way) you simply strip the old plating, re-plate it, hone it and you are ready to go again. Every cylinder that is constructed in this manner is subject to the same re-conditioning practices. Another advantage is that in the event of a some kind of catastrophic failure which damages the bore (i.e. valve breaks) then the process remains the same except that once the bore is stripped you just weld up the damage, bore it, re-plate and carry on as normal.

4. Let's talk about the construction of the plating itself. Nickel-Silicon-Carbide is composed of just that. Now the percentages can be, and in many cases are, a "witch's brew". These percentages are essentially recipes in the industry and are very closely guarded. Too much silicon carbide and it's bad. Too little and it's bad. Regardless, the silicon carbide requires diamond stones to hone it. Now that's hard gentlemen. With that said, you always have a cylinder wall that is harder than the ring. Just to clarify, the ring actually doesn't ride on the cylinder wall continuously but rather a film of oil. Anyway, if this is the case then the ring doesn't wear the cylinder out of round. If the cylinder material and geometric structure is appropriate then the bore doesn't distort and go out of round. Bottom line, better ring seal. It should be of note as well that nickel-silicon-carbide bore also have a lower coefficient of drag on the ring than a standard liner which also equates to less heat and longer ring life.

3. A comment was made about it being expensive for 3 extra inches. Boy could that go a LOT of wrong directions. Anyway, back on point, you are buying the extra displacement but moreso the durability and dynamics of design than anything else. The plating itself is 10 times more durable than OEM cast iron. That, in and of itself is key. If you continue to ride and eliminate even one tear down and re-build from cylinder wear and warpage then you have MORE than paid

 

KTM uses Nicasil sleeves on their dirt bikes and they are awesome. I went through 2 sets of rings and never even had to hone the cylinder.

 

It sounds like it may be the way to go. They are similair in price to the HD big bore jugs (not as inexpensive as boring your existing cylinders) and it sounds like they will outlast them.