do I need to hone this?

[Henry Schmidt]

If by "grape" hone you mean "bottle brush" hone, don't do it. Although the hone will not penetrate the Nikasil plating it will make ridges in the Nikasil that will cause premature ware on the rings. If you use Geotze rings ( OEM) you will be lucky to get 20k miles before the ring gap is out of spec.. Hastings rings tend to last a little longer but not much. Ask any of the people who recommend a bottle brush hone "if they have taken their engine apart and checked the ring gap lately". We built a fair number of race engines and in doing our development we had a chance to try this obvious option for cylinder prep and at this point have decided that for street use ( an engine that will be together for more than a few thousand miles) this is a bad option. Don't do it.

[Rot 911]

Well I guess I am F*cked then cause I did it. I'll just keep my fingers crossed and hope for the best.

[nreed]

In the end I just used a little bit of scotchbrite on mine...I was afraid to do anything more.

[Henry Schmidt]

Hi Kurt
It was not my intention to bum your day. Perhaps the use of a synthetic oil will add to your ring longevity. There are also some oil additives that can aid in cylinder repair.
Formula 3 sold by Lubrication Specialist Inc. has a product that was developed for rifle barrels that can do miracles in the treament of metal surfaces.
858-565-2700

[dhoward]

Your day is not ruined Kurt. I got my information from the folks at US Chrome. They have done many Nikasil 2-stroke cyls for me and a hundred or so of my closest friends. (www.dirtrider.net)(welding, replating, etc.). These things get abused. Cold seize, broken pistons, etc..
Unless the plating flakes, and sometimes it does, if there's been damage, it'll be fine. Nickasil is harder than Silicon-carbide. The grape hone is faster than scotch-brite for removing the glaze.

[Henry Schmidt]

Originally posted by dhoward
I got my information from the folks at US Chrome. They have done many Nikasil 2-stroke cyls for me and a hundred or so of my closest friends. .

Hey I didn't think of that. A two cycle with an oil ring. For that matter a two cycle that has a bore that lasts for 100K miles.

When properly installed and maintained there is no reason why a new set of Mahle Nicasil Ps & Cs shouldn't go 200k miles. If your engine had 100K on it when rebuilt the Ps & Cs still have a good 100k left. Why not give yourself every chance to get it?

[dhoward]

I think you missed the point.
But hey, you're the new expert on Nikasil.
Everyone do what Henry says, I'll just listen.

[Henry Schmidt]

Expert is an interesting term. Do I detect some.... lets not go there. This bulletin board is for enthusiasts to communicate personal experiences to one another in an attempt to guide each other around pitfalls. I related my personal experiences. If you were offended by something I said, I apologize.

[afterburn 549]

could you post the pic after it has been in service for awhile the rest of want to know if it really can be done.......................

[dhoward]

As was I. Not offended .
And no, you didn't detect any....

[Doug Zielke]

Henry,
I for one appreciate your arrival on this forum. You are obviously in the business, and that gives some weight to what you say. Thanks for posting here.

[KobaltBlau]

What Doug said. I appreciate your expertise also, Henry.

[jgparker]

This would be a very boring board if we didn't get new and dissenting ideas. Henry is not a full fledged Plelican pod person yet, so he is walking on some of the sacred cows we have already beaten to death. Thank goodness we have him, and John Walker, and CamGrinder, and Steve@rennsport, and yes Snowman too to bring their experience and to stir the pot. Please keep the opionions flowing, and I'll keep my common-sense filter on.

Thanks,

JP

[Alan Cottrill]

Originally posted by jgparker
yes Snowman too to bring their experience and to stir the pot.

Where has Snowman been? I haven't seen him post for a while.

[Rot 911]

Well I have been doing research on this issue and here are some of my results:

http://www.hiperf.com/acatalog/Online_Catalog_Shop_Tools_45.html Flex Hone(Reference #FLEXHONE)
Fast, efficient cylinder deglazing and cross hatching insures immediate ring seating - without appreciable stock removal. These unique flexible hones consist of globules of silicon carbide laminated to the ends of high density nylon. Ideal for port deburring of two-stroke engines, and essential for obtaining a plateaued finish. Powered by a portable electric drill. NOTE: 320 grit is recommended for Nikasil plated cylinders.


From Wayne on a BMW board:
The Nikasil cylinders can be honed and reused. They typically have a ‘MAHLE’ stamp on the lower side of the cylinder. The nickel-carbide surface needs to be lightly honed with a special silica impregnated tool, or what is commonly known as a grape or flex hone. The surface properties are too hard for normal tool steel honing machines. You should only have an expert familiar with the Nikasil cylinders perform the honing process.

From a motorcycle rebuilding page: http://www.eric-gorr.com/techarticles/twotopweb.html
Honing the Cylinder Bore

Many people have emailed me with questions regarding honing cylinder bores. If you want to buy a hone to deglaze bores or polish off small scratches, then a ball-hone is the best choice. Ball hones are manufactured by Brush Research in Los Angeles, under the brand name Flex-Hone. These hones are available under different labels and they are most easily available from auto parts stores. Buy a size that is 10% smaller than the actual bore size. These hones are available in several different materials and grits but the profile that bests suits both steel and plated cylinders is aluminum oxide 240 grit. A ball hone cannot remove material from the cylinder bore, especially on the hard nickel plated bores. However a ball hone can polish down the peaks of the original hone scratches and increase the bearing ratio. In other words the piston will be touching a greater percentage of the bore. Sometimes that makes the piston wear quicker but if you have to ball hone the bore to remove scratches, it's a compromise. The one type of hone that you should never use on a two-stroke cylinder is a spring-loaded finger hone. The sharp edges of the stone will snag the port edges and most likely damage the hone and the cylinder.

As DHoward has stated previously, apparently it is common practice in the motorcycle industry to use a flex hone on nikasil cylinders. Only time will tell if it leads to accellerated ring wear in a 911 engine.

[Doug Zielke]

Originally posted by Alan Cottrill
Where has Snowman been? I haven't seen him post for a while.

Well, it is summer, doncha know?
He just melted.
At last report, all that was left was a pool of brownish water,
and a grape hone.

[dhoward]

Kurt, Eric Gorr is a personal friend of mine and well respected in high-performance motorcycle circles...

[Rot 911]

I think I have finally found some good information. It appears that the Nascar race cars are starting to use Nikasil cylinders. It appears the Porsche, as usual, was way ahead of its time. Anyway here is the link and part of the post. It is quite long.
http://www.babcox.com/editorial/ar/eb110242.htm

The Smooth Science of Cylinder Honing
By Larry Carley
Technical Editor
lcarley@babcox.com

Honing Hard Materials
In recent years, Nikasil coatings have provided a challenge for engine builders. Nikasil is a hard coating of nickel and silicon carbide about .0025½ to .003½ thick that is applied to cylinder bores to improve wear resistance. Invented by the German firm Mahle, Nikasil was originally developed for the Mercedes Wankel rotary engine. It has been used by BMW and Porsche in some of their engines, and is also used in many chain saw engines, some motorcycle and marine engines, and even many NASCAR Winston Cup engines.

Goodson’s Jensen says PERs have had success honing Nikasil treated cylinders with diamond. But for smaller shops that have only portable honing equipment, you can’t exert enough pressure with diamond to hone Nikasil. The best advice here is to use #220 silicone carbine and just do a couple of strokes to deglaze the cylinder. If a cylinder has to be bored to oversize, cut it out with a boring bar and then hone in the usual manner to achieve the desired dimensions and finish.

Ed Kiebler of Winona Van Norman in Wichita, KS, says new harder coatings on cylinder walls are forcing shops to change to diamond honing and to upgrade their equipment.

"I see a lot of shops who are interested in diamond but who don’t fully realize what’s involved in the diamond honing process. Diamond takes a lot of pressure to cut. Some people use diamond on portable hones, but realistically you can’t get enough pressure to make the diamonds perform well. Having said that, I truly believe the new harder cylinder coating materials are going to force people to go to diamonds," says Kiebler.

"The two-cycle stuff is all Nikasil. Now the outboard engines are going to Nikasil, too. All the NASCAR Winston Cup shops are using Nikasil cylinders. If it’s good for NASCAR, it’s not going to be long before you start seeing it in OEM engines," Kiebler explains. "The time is coming when you’re going to have to use diamonds if you’re going to hone Nikasil cylinders."

Kiebler says all most shops do is slightly roughen Nikasil cylinders. "You don’t really remove much material. The Winston Cup shops are running some of these motors five races before they redo the cylinders. The Nikasil coating really extends ring life and cuts down on ring wear."

[Rot 911]

Quick follow up on the Nascar:
http://www.ramaircraft.com/nascar-nickel-cylinders/nascar-using-nickel-cylinders.htm

NASCAR Winston Cup, BMW, and Porsche!

These industry icons of engine performance are using Nickel/Silicon Carbide cylinder bores to achieve durability, referred to as Nikasil.™ From experience, they know that cylinder bore quality plays a huge role in reducing friction and blow-by for improved engine performance and durability, and they are not in a position to be wrong about cylinder performance.

RAM has achieved durability too! No premature wear or corrosion
from 9,600 cylinders delivered during the past five years. Engine Components, Inc. ( ECi ) offers us a proprietary nickel and silicon carbide composite applied to the bores of their PMA new cylinders.
We use either their PMA new cylinders, or we have them apply their composite to the new OEM cylinders we use.

Following are quotes from Engine Builder Magazine, Nov. ‘02, Vol. 39, No.1. The Smooth Science of Cylinder Honing, by Technical Editor, Larry Carley. He notes:


“In recent years, Nikasil™ cylinder bore coatings have provided a [honing] challenge for engine builders. Nikasil™ is a hard coating of nickel and silicon carbide about .0025” to .003” thick, applied to cylinder bores to improve wear resistance.”

“Invented by the German firm Mahle, Nikasil was originally developed for the Mercedes Wankel rotary engine. It has been used by BMW and Porsche in some of their engines, and is also used in some motorcycle and marine engines, and even many NASCAR Winston Cup engines.”

Kiebler explains,“NASCAR Winston Cup shops are using Nikasil™ cylinders. If it’s good for NASCAR, it’s not going to be long before you start seeing it in OEM engines.”

[Henry Schmidt]

Some of the statements in this post got my interest peaked. The statements totally contradict what I’ve seen with my own eyes. Now what? I talked to a friend of mine, John Edwards, the owner of Costa Mesa R&D and the author of SUNNEN’S COMPLETE CYLINDER HEAD AND ENGINE REBUILDING HANDBOOK and we did some testing and here’s what we found.
We used a Mitutoyo SJ – 201 Profilometer to test the smoothness of our test cylinders.
We had one new Nikasil cylinder; one unmolested Nicasil cylinder w/ 104,000 miles and one used Nikasil cylinder sacrificed for this test.
The used cylinder was lightly honed with a 320-grit hone bottle bush hone specified for use with Nikasil.
Unmolested cylinder was cleaned, as was the new cylinder.
The test.
The unmolested cylinder measured 3.0 RA, the new cylinder measured 4.9 RA, and the lightly honed cylinder measured 10.5.
10.5 is way too rough!! Because the rings are soft they will ware out before the cylinder gets smooth. In other applications the crosshatch marks will smooth with ware, and the rings will seat.
Mahle says in their literature that the honed surface of their Nikasil cylinders should be 4.2 to 6.0. Our test proves that they start that smooth.
I have read in some literature that cast iron rings as used in Nicasil cylinder want an RA surface of 18-25.
I guess that works for Fords and Chevys but we’re talking about Porsches here and as much as I love Nascar I will not use Nascar specs to build my Porsche engines. It seems that short-lived engines in motor cycles might benefit from this information.
I read through this thread and one thing seems perfectly clear. People will believe what they want, as they should.
One thing that is true: “The truth is not dependent on your belief”. In other words “it’s true, weather you believe it or not”.
An ostrich can’t see the true because is head is buried in the sand, time to pull your head out. Porsches are not like other cars, and neither are their engines. Look at the pictures and see for yourself.

Here is some information about grit and RA specs.
http://www.babcox.com/editorial/ar/eb110242.htm
If you’re switching from conventional stones to diamond, you’ll generally have to use higher grit to achieve the same Ra (roughness average) when finishing a cylinder. For example, if you have been using #220 grit conventional stones to finish cylinders for chrome rings; the equivalent diamond stones might be a #325 grit. If you have been using #280 grit conventional stones to hone for moly rings; the diamond equivalent might be #550 grit stones. The actual numbers will vary somewhat depending on the brand and grade of the stones.

A cylinder bore must have a certain amount of cross hatch and valley depth to retain oil. However, it must also provide a relatively flat surface area to support the piston rings. Ring manufacturers typically specify a surface finish of at least 28 to 35 Ra for chrome rings, and 16 to 25 Ra for moly faced rings. These numbers can be easily obtained with diamond stones and brushing, say those who use this honing technique.

One rebuilder we spoke to says he uses #325 grit diamond stones to end up with an Ra finish in the 20 to 25 range, which he feels is about right for moly rings. For some applications, though, he uses a #500 grit diamond to achieve a smoother finish in the 15 to 20 Ra range.

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