Honing Nikasil Liners
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Honing Nikasil Liners
I have been offered a Dodge R5 block with Nikasil liners for my drag project. The block is finish machined ready to go. When it's time to rebuild, what special processes are involved in re-honing the bores. The workshops I use have Sunnen Hones, i cannot recall what type. What stones should be used? What do they cost approximately?
Just wanting to work out whether I should take it, or go with a cast iron bore block(i have the option of either)
Thanks
AL....
Just wanting to work out whether I should take it, or go with a cast iron bore block(i have the option of either)
Thanks
AL....
Alan Jones
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Re: Honing Nikasil Liners
Sunnen make stones for use with Nikasil surfaces. The abrasive material is boron carbide.
They are labeled CBN/Borazon and carry prefixes of NM, NR or NV.
Diamond can be used for metal removal but does not produce the proper finish on Nikasil.
Use the CBN stones and hone to a plateau finish.
They are labeled CBN/Borazon and carry prefixes of NM, NR or NV.
Diamond can be used for metal removal but does not produce the proper finish on Nikasil.
Use the CBN stones and hone to a plateau finish.
Re: Honing Nikasil Liners
If the block is ready to assemble now.
And the question is how to hone on a rebuild.
What I have done on Porsche, BMW, and Mercedese blocks on rebuild is use a ball hone and just scuff the cylinders.
Kind of a de-glazing.
It must of worked because there were no complaintes.
And the question is how to hone on a rebuild.
What I have done on Porsche, BMW, and Mercedese blocks on rebuild is use a ball hone and just scuff the cylinders.
Kind of a de-glazing.
It must of worked because there were no complaintes.
Re: Honing Nikasil Liners
What are the wear characteristics for Nikasil bores? How much longer will they last before needing a re-hone?
Thanks
Thanks
Alan Jones
It's Ok to disagree, just don't be disagreeable!
It's Ok to disagree, just don't be disagreeable!
Re: Honing Nikasil Liners
How do they go with Methanol?
Thanks
AL....
Thanks
AL....
Alan Jones
It's Ok to disagree, just don't be disagreeable!
It's Ok to disagree, just don't be disagreeable!
Re: Honing Nikasil Liners
Nikasil is much harder that steel/iron. You will wear out rings long before Nikasil.
It works just fine with ethanol and methanol (and nitromethane mixes). But with aluminum bores, the cooling effects of alcohols tend to want different tolerances, but you need to watch your bore growth, distortion, and piston cam grind closely. Cold scuffing can be an issue if you don't pay attention when using tight tolerances.
It works just fine with ethanol and methanol (and nitromethane mixes). But with aluminum bores, the cooling effects of alcohols tend to want different tolerances, but you need to watch your bore growth, distortion, and piston cam grind closely. Cold scuffing can be an issue if you don't pay attention when using tight tolerances.
Re: Honing Nikasil Liners
How much additional clearance would be required for Gasoline and for an alcohol based fuel?W. Tripp wrote:Nikasil is much harder that steel/iron. You will wear out rings long before Nikasil.
It works just fine with ethanol and methanol (and nitromethane mixes). But with aluminum bores, the cooling effects of alcohols tend to want different tolerances, but you need to watch your bore growth, distortion, and piston cam grind closely. Cold scuffing can be an issue if you don't pay attention when using tight tolerances.
Thanks
Alan Jones
It's Ok to disagree, just don't be disagreeable!
It's Ok to disagree, just don't be disagreeable!
Re: Honing Nikasil Liners
Does one ever have to do anything to Nikasil plated cylinders? I am no expert, but I vaguely remember that when I was a kid the two-stroke small bike engines that we played with would have to be totally destroyed beyond repair before there would be anything wrong with the Nikasil wall.
Based on hearsay, the only common problem with Nikasil is problems with very high sulfur fuel. http://www.google.com/search?hl=en&sour ... =&gs_rfai=
I think the reason why Nikasil is not used more commonly is the initial plating cost tends to be pretty high.
Based on hearsay, the only common problem with Nikasil is problems with very high sulfur fuel. http://www.google.com/search?hl=en&sour ... =&gs_rfai=
I think the reason why Nikasil is not used more commonly is the initial plating cost tends to be pretty high.
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Re: Honing Nikasil Liners
I would not consider changing from steel to aluminum bores an improvement for most applications. Maintaining bore roundness and ring seal in high specific output engines will always be a concern. Nikasil does make for a long lived bore, that is considerably lighter than a steel sleeve (up to a pound+ lighter per bore), and it is regularly used in motorcycle and outboard marine engines by OEMs where high rpm and engine weight is a concern.
I have run motorcycle and outboard marine engines with steel sleeves, and then converted to Nikasil sleeves. However, many other things were changed at the same time, so a direct comparison is not possible. But I actually tighten clearances (from the OEM clearances) changing from steel to aluminum/nikasil sleeves. The biggest issue to bore clearance and piston alloy/cam grind is in two-strokes - always an issue when you tighten clearances. I have not had these same issues in four-stroke engines with Nikasil bores.
I have had no issues running ethanol or methanol in Nikasil bores running slightly tighter than stock clearances, but I have paid close attention to coolant temps in these engines. I have seen methanol engines (two-stroke and four-stroke) cold scuff when run hard with cooler engine temps (drag use). Running up to 50% nitro mixes, I use a slightly looser bore.
Nikasil is fairly maintainence free, and the cross hatch from honing tends to last much longer than in steel/iron bores, even though it starts out much finer (from the stones used) than in steel/iron bores. It tends to provide a long life with a much finer and slicker finish that can free up a few hp compared to the same engine running steel sleeves. Due to it being used in aluminum bores, it does transfer heat more readily, and bore roundness and distortion tends to be more of an issue. In some engines I have had the Nikasil plating thickness doubled to improve bore roundness at operating temps.
[I may be over-inflating the bore roundness/ring seal issue with aluminum bores. It is common practice to bore many stock cylinder motorcycle engines 3mm (0.118 in.), for drag use, and many do not consider maintaining bore roundness an issue. But I am a bit particular about ring seal.]
If Nikasil had problems with the higher sulfur fuels we used for decades in the USA, it would have shown up in all of the motorcycles and outboard marine engines that have used it since the 1990's. Some of the MMC cylinder liners have shown larger issues with higher sulfur fuels. But the pump fuels available in the US the past few years, and in most of the world for decades, are much lower in sulfur content. Racing fuels are another matter, but I have not seen any issues from fuels. In fact, oxygenated race fuels and alcohols tend to have issues in steel bores more than in Nikasil plated ones when not purged well (or at all in Nikasil bores).
For more detailed information, I would suggest contacting US Chrome, Millenium Plating, and Langcourt LTD. I have used all three of these companies for plating over the years.
The biggest downside is cost to install aluminum sleeves and have them bored, plated and honed. Boring, plating, and honing can cost USD $100-$150 per bore. Cost can vary by the number of bores, and the bore diameter. Depending on the company, some will charge a fixture fee for new engines that they do not see much of a market for plating. Langcourt LTD cannot plate engines larger than inline fours. But US Chrome and Millenium can handle V6 and V8 engines.
I have seen times when the Nikasil plating did not adhere well to the aluminum bores, and later flakes off - damaging the engine. It is RARE, but it does happen when the bores are not preped well by the plater.
I hope this helps.
I have run motorcycle and outboard marine engines with steel sleeves, and then converted to Nikasil sleeves. However, many other things were changed at the same time, so a direct comparison is not possible. But I actually tighten clearances (from the OEM clearances) changing from steel to aluminum/nikasil sleeves. The biggest issue to bore clearance and piston alloy/cam grind is in two-strokes - always an issue when you tighten clearances. I have not had these same issues in four-stroke engines with Nikasil bores.
I have had no issues running ethanol or methanol in Nikasil bores running slightly tighter than stock clearances, but I have paid close attention to coolant temps in these engines. I have seen methanol engines (two-stroke and four-stroke) cold scuff when run hard with cooler engine temps (drag use). Running up to 50% nitro mixes, I use a slightly looser bore.
Nikasil is fairly maintainence free, and the cross hatch from honing tends to last much longer than in steel/iron bores, even though it starts out much finer (from the stones used) than in steel/iron bores. It tends to provide a long life with a much finer and slicker finish that can free up a few hp compared to the same engine running steel sleeves. Due to it being used in aluminum bores, it does transfer heat more readily, and bore roundness and distortion tends to be more of an issue. In some engines I have had the Nikasil plating thickness doubled to improve bore roundness at operating temps.
[I may be over-inflating the bore roundness/ring seal issue with aluminum bores. It is common practice to bore many stock cylinder motorcycle engines 3mm (0.118 in.), for drag use, and many do not consider maintaining bore roundness an issue. But I am a bit particular about ring seal.]
If Nikasil had problems with the higher sulfur fuels we used for decades in the USA, it would have shown up in all of the motorcycles and outboard marine engines that have used it since the 1990's. Some of the MMC cylinder liners have shown larger issues with higher sulfur fuels. But the pump fuels available in the US the past few years, and in most of the world for decades, are much lower in sulfur content. Racing fuels are another matter, but I have not seen any issues from fuels. In fact, oxygenated race fuels and alcohols tend to have issues in steel bores more than in Nikasil plated ones when not purged well (or at all in Nikasil bores).
For more detailed information, I would suggest contacting US Chrome, Millenium Plating, and Langcourt LTD. I have used all three of these companies for plating over the years.
The biggest downside is cost to install aluminum sleeves and have them bored, plated and honed. Boring, plating, and honing can cost USD $100-$150 per bore. Cost can vary by the number of bores, and the bore diameter. Depending on the company, some will charge a fixture fee for new engines that they do not see much of a market for plating. Langcourt LTD cannot plate engines larger than inline fours. But US Chrome and Millenium can handle V6 and V8 engines.
I have seen times when the Nikasil plating did not adhere well to the aluminum bores, and later flakes off - damaging the engine. It is RARE, but it does happen when the bores are not preped well by the plater.
I hope this helps.
Re: Honing Nikasil Liners
Hi, I have a block Nikasil liners that show a sharp angle at the bottom where the liners end and the piston is at BDC:
what kind/type of tool would you use to deburr there?
I know Nikasil is quite annoying and operation could be risky
what kind/type of tool would you use to deburr there?
I know Nikasil is quite annoying and operation could be risky
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Re: Honing Nikasil Liners
Re: Honing Nikasil Liners
One of my very good friends recently use to build a LOT of higher end 2 stroke engines for MX racing. He would have his parts plated at Millenium coatings... and it was TOUGH. At the time (5-10 years ago) he said the quality of coatings varied quite a bit among providers.ptuomov wrote: ↑Sat May 08, 2010 8:00 pm I am no expert, but I vaguely remember that when I was a kid the two-stroke small bike engines that we played with would have to be totally destroyed beyond repair before there would be anything wrong with the Nikasil wall.
I think the reason why Nikasil is not used more commonly is the initial plating cost tends to be pretty high.
What amazed me, is that there were multiple occurrences where a bike would seize a piston... and all he had to do was use a hand held drill hone to clean out all the metal, and install new piston/ring! Blew my mind...
Anyway, that stuff is TOUGH! Hard to justify the cost with a V8, especially with shipping... but it is the Shiz-Nit when it comes to dirt bikes!
Re: Honing Nikasil Liners
Any particular grinding stone or carbide burr would you use? I'm a bit afraid of a Nikasil flake come off as soon as I touch the linersmt-engines wrote: ↑Thu Sep 24, 2020 11:38 ama grinding stone or carbide burr
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Re: Honing Nikasil Liners
Matt80 wrote: ↑Thu Sep 24, 2020 1:46 pmAny particular grinding stone or carbide burr would you use? I'm a bit afraid of a Nikasil flake come off as soon as I touch the liners
I would try and use the appropriate curved rat tail file and see if you can't knock the edge off that way.
run the file around the bore not up and down.
should have been chamfered before nikasil.