So.....would you pay extra for Nikasil cylinders?

I'm in the process of having some cylinders reworked and have the option of having my cylinders brought back to standard dimensions.....and can either have Channel Chrome or a Nikasil coating.

For about what amounts to a $400 total cost.....to have a Nikasil coating applied to all the cylinders.

Is it worth it?......I'm thinking not.

Performance-wise the Nikasil's are easier to break in and perform more like conventional steel cylinders. Chrome takes longer to break in and can use more oil.....which can be a negative for some who don't understand "where" the oil is going.

Also, CermiNil is the ECi brand name for a similar coating. Nikasil coatings are very common in the racing world and the air-cooled aluminum Porsche engines love em.

 

Chrome is history! Is the $400 worth the risk when you are spending $7K or more. What engine/airplane do you have. Chrome works better on some installations than others. Charlie Melot

 

$400 maybe a low cost investment....if they hold up more than a few hundred hours and has good resale sparkle should I need to sell.

This is going into my Bo...TSIO-520D. I see where a guy on the Beechtalk board had some issues....but everyone seemed to think it was detonation and not the materials.

I'm not spending $7K....since this is a DIY job, But, bout half that.

 

Is it worth it to replace the cylinders with "reworked" rather than new? the admittedly limited experience I had with reworked convinced me to buy new the next go around.

 

Lessee.....$450 per cylinder to replate cylinder walls, port polish, new piston & rings, and redo valves....vs....$2,000 for new?

depends.....I'm an A&P/IA...so, yes it's very worth it to me.

 

So you're doing all the machine work yourself and just subbing out the plating? Seems like a pretty low cost to rework each cylinder or there really wasn't much wrong with them to begin with. Most of the cylinders I've sent in are so far gone and new cylinder kits are so cheap it doesn't make a cylinder repair economically viable.

Back to the original question. As far as I know, the motorcycle/ATV industry shifted away from chrome plating back in the '70s or early '80s toward nikasil. The claim I always heard there was that the chrome really wouldn't hold oil and the nikasil was better at keeping the oil where it needed to be. That tracks with what the aviation industry seems to have observed with the old chrome cylinders (oil consumption, blowby, etc.) vs. the newer cylinder finishes. If it were me I'd go for the nikasil, hoping that it cuts down on the problems normally associated with chrome bores.

As a side note, if you go this direction you might consider doing some investigation into proper cylinder and ring prep to promote good break in. I know that what Suzuki recommends for preparation and break in for my current motorcycle is quite different than the generally accepted practices used in the aviation industry. I'm not advocating a deviation from the aviation practices but it is something worth noting, investigating, and making an educated decision on.

 

All I've gathered on the Nikasil break in is .....it's very easy and fast. The last process of the plating involves a special "hone" which is a diamond cross hatch cut. This cut assures a fast ring break in.

It all sounds positive so far....

 

I put nikasil ECI cylinders in my O-320 and break in time was really fast. On the first or second time around the pattern I'd see the cyl head temp climbing, plateau and then drop down to what I'm used to seeing in my plane. Oil consumption was much lower than I'd ever seen in chrome cylinders and compared to the cylinders I replaced (chromed) the consumption dropped to about what I'd expect of a broken in engine. This occurred in the first hour of running compared to 15-30 hours with chrome. I think the nikasil is worth it though in real life I think you'll have more issues with guides, valves, seats and heads then you will wearing out the cylinder bore so nitrided may not be a bad thing either.

Frank

 

I've seen Chrome cylinders take 3 sets of iron rings to break in and stop using oil.
YMMV

 

These days when motorcycles can get 100K miles on a set of cylinders/pistons/rings with nikasil, I see no reason why anyone would use chrome.

 

that does it.....I'm goin with the Nikasil.

 

I have an aversion to the name because of Jaguars failure with it in the late 90s, but I think that was down to high sulphur level in the fuel. Curious to know how it goes.

 

well....I'm just gonna call em....Nickel coated.

not CermiNil, not Nikasil, or not any of the other trade names associated with the similar Nickel coating.

 

Don't be fooled by the inferior coatings NiC3, CermiNil, or Nikasil, instead use VAGasil!

 

now....that sounds like one of those LOP....lean forward solutions.

 

Well, call 'em silicon carbide. The nickel is gone after break-in.

 

Good choice!

 

so Tom....how would you log this?

 

I replaced all six of the original TCM cylinders on my O-300 with ECi Titan CermiNil cylinders, and have been very pleased with them for over 700 hours. The decision was made after two stuck exhaust valves in two different cylinders causing some loss of power and teeth rattling vibration while in cruise, and because the airplane (a 1963 127D) sat for weeks at a time when I was traveling internationally for work. The CermiNil provides superior protection against wear and rusty cylinder walls, and unlike the TCM O-300 cylinders the ECi cylinders rotate the exhaust valve stems a few degrees every time the valve opens and closes, preventing the carbon buildup in the valve guides that causes the valve sticking.