The LN engineering guys have had a LOT of success with the aircooled jugs, Shad is the guy to talk to at LN or Jake at aircooledtechnology.com he's an engine builder and sells the LN stuff. He's beat the hell out of their stuff, 10's of thousands of miles and tons of dyno time.

As to putting up with low quality fuel, my Bunton mower has a Kohler engine with nikisil bores. 1600+ hours and the bores specs are dead on and still have the cross hatch. This thing gets run with the crappiest 87 (ron+mon/2) gas with whatever water condensates in the tank.

in other words DO IT!!!

 

Iv'e got 5 or 6 set brand new twin dizzy 12A housing and a few new rotors if anyone is interrested send pm.

About the Nikasil i was talking with a company here in sweden who work with Chrome and Nikasil plating and the only issue they could see were the the grinding process.

 

I can help. you can use Nikasil on the Rotor Housings,Its a plating process but the plates will last longer If you plasma spray them,with a surface coating ,it takes a lot of lapping to do a Plates surface especially the center plate If its cast you have to prep it with a pre- lap to remove the Factory,Nitride surface then plasma ,then Lap again It takes about a full days lapping to return the surface to stock dimensions,then it has to be finish lapped with another lapping System.for final finish prep.I know because I do It, and have been for about 10 years I like the Idea of the Aluminum castings I considered that Maybe we could work together and end up with an all alum RotaryBlock................HmmmmmmmmmmKeep In touch Fred

 

what do you charge for such a service ?

 

Patman I have done coatings for years What do you want to do

 

the process is mostly Labour related the plasma is cheap about 100 per plate but it takes 1.5 to 2 hrs to lap the plates per face , to remove the plate wear and surface nitride surface then media blast that surface,then, plasma spray about 3-5mil of surface coating on , then 7 to 8hrs of lapping, to lap it back to factory specs , then finish lap to surface specs for quick break in . as far as costs go your biggest concern would be shipping Heavy parts back and forth. The lapping on 1 engine can be 40 to 45 hrs alone and the last time I checked lapping was about $40 an Hr It seams like a lot but if you figure the end result will likely last through 4 -typical 100,000 mile rebuilds

 

^ What is done about the coolant seal grooves? Are they also built back up to factory spec with the nitride?

 

Yes they are but we are only talking about 3 to 5 thousands , which is, not an issue ,It can actually help with sealing of the o rings ,I have over the years seen a lot of damage under the rubbers from overheated engines.

 

you are plating nikasil over top of the factory chrome on the housings? I wouldn't think it would adhere very well?

My plan for this is to build machines to do the pre-grind and post-grind process, and have someone else do the actual coating, if you have a good supplier for this that would certainly be useful. All that labor time is what I am trying to cut down on, I can easily build a machine/jig to machine surfaces on both plates and rotor housings..

Pat

 

Only 3-5 thousandths though?

Here is what I am thinking, If you lap off the entirety of the nitrite coating (8 thousands I think?) then your are removing 8 thousands from the coolant seal grooves. Then when you build it back up you are building up everywhere. So even if you build up the coolant seals walls you are also building up the coolant seal grooves.

Thus you have still removed the 8 thousands and, in my opinion, out of a safe spec for the coolant seal grooves.

 

One of my customers uses Nikasil on their housings. It's a 35cc UAV engine running NRS ceramic seals. He reports 250 hrs running time with no measurable wear.

 

Patman For the rotor housings you do not plate on the Chrome surface, it is removed,by de chroming , then treated .The only one who has done this locally Is my friend Mark who owns JHB, he can do the rotor housings,as far as the plates are concerned the Nitride surface is removed by lapping its a very thin surface 1 to 1.5 thou ,however, the wear on most plates is usually ..................3 to 5 thou , which I remove with lapping,we tried grinding before and it works but you still have to lap to get the surface prepared properly,you can try to cut corners by other methods but, I have been there, and I learned from my mistakes, save yourself some time and research nitride surface treatments,as well as nikasil

 

I would imagine that the Nikasil surface isn't really tested all that much. From the sounds of things, every manufacturer went their own way when it came to surface coatings. Since Mazda is the only company that produced successful cars with a rotary, its the only one we know about it.
I have found some information on non Mazda rotaries though, there is one paragraph of information here.
http://books.google.com/books?id=Vvy...0engine&f=true
It reads
“Other Wankel builders have used various solutions, Mazda uses carbon and aluminum sealrls on a chrome-plated aluminum face, NSU uses iron-based Ferro-Tic seals against an Elnisil (silicon carbide) plating. Mercedes-Benz is experimenting with silicon nitride seals on a nickel-silicon surface. GM is going its own way. The Iron track will not be plated, but will have a light metallic coating sprayed on. The seals will be a low cost ceramic “
This is from Popular Science from the '70s, so probably should be taken with a grain of salt. Especially the part about how Wankels will completely eliminate pistons....
Another resource I am eying to purchase is here: http://books.google.com/books?id=IB2...page&q&f=false
It looks like it has some information on non-Mazda Wankels and might be another place to look if Nikasil was found to be unsuitable.________________
1988 RX7 GTU - Modded with stuff
2008 Subaru Legacy GT Spec B - Not modded with stuff
Buy your Haltech from CLudwig!!!

 

i thought JHB was no longer in business? If they are still around I assume they have the machines that I was planning to develop, so it wouldnt make much sense for me to do it.

Hand lapping is not necessary at all if the machining is done right. Grinding is a pretty loose term. I know about nitriding, but I have issues with this- the first being that it is obviously not sufficient, as stock plates are nitrided and generally are worn through the coating before 100k miles. The second is that I would like to provide a uniform coating on both the housings and plates, and nitriding obviously will not work on housings. Nitriding also does not enhance lubrication as does nikasil.

 

The trochoid would be an easy CNC program. There has to be a grinding wheel or drum that works in a spindle. Though I'm not familiar with them. 20k+ rpm CNC machines are pretty common now. I don't think a regular jig grinder would do the job.

I wonder how accurate the trochoid is? I thought I read on this forum from someone that checked them and they said there was big differences from one housing to the other. I don't know. I've CMM'd a lot of things, but not the trochoid.

 

Patman, check out Plasma sprayed coatings I use a chrome carbide plasma spray on my plates which when applied leave a slightly porous surface which is excellent for retaining oil, its hard as can be and will out perform, a Nitrided surface by miles, as far as Nikasil is concerned a lot of high performance Snow sleds use nitride cyl bores and they have been for some time ,one more thing, when using a plasma sprayed surface, if you damage it by blowing up your engine,(hardly likely) you can, respray the surface,once more and relap ,which you can not do with a nitrde surface. either way,all i can say is I have several engines which I have applied the coating to and sold to customers,and it has proven itself both in lowering the Friction as well as the Engine operating Temp .....................................

 

the proof will be in the pudding, get it done on a HI boost turbo mazda rotary!!

N/As last forever(almost),, and turbo engines dont last long on continuous boost!

gitter done, i been waitin for 20yrs.

 

Do you have anymore information about Plasma Spraying? Where do you have it done? I've never heard of it, but it sounds like it's used in aircraft engines. Very neat process.



http://www.zircotec.com/page/plasma-...g--general-/39

And a few random links...

http://brycoat.com/pvd-crn.html

http://www.purtech.com/spray.asp

http://www.benderus.com/ThermalSpray/thermalsprays.html

 

I believe the issues with nikasil coatings have been:

>poor adhesion due to improper surface preparation
>nikasil tends to "crack" or strip off with temperature changes, especially if not applied properly, even in aircooled cylinders.
> US CHROME is who I would be taling to about re-lining Mazda housings and plates, they have been at it longer than anyone else and will be able to provide input as to what will and will not work.
>CERMET housings and plates are still available froma couple of sources, but are fairly expensive.

I myself am going to have a set of rotor and "main" bearings coated with a DFL type coating from Embee, as well as having them coat the rotor faces with a ceramic thermal barrier coating. I have theories about using a Casidium type coating on rotor housings and plates, but am still trying to determine if the super-hard Casidium coating will survive the expansion cycles of the rotor housings. I am also going to have the intake ports thermal barrier coated, along with the intake runners themselves. All of this is more for friction/heat management/wear resistance more than to restore a damaged housing, but my understangin is that some coatings have developed to the point that they can certianly be used to repair damaged bits.

One thing to consider is that things that were not repairable or not worthwhile to repair even a short time ago is not too big a deal anymore. A good example is cracked rear S4/5 irons. Once upon a time a crack was the kiss of death, but with sprayed-plasma and other technologies these are now relatively easily and permenantly repairable at a reasonable cost, once you find someone with the equipment to do it. Irons can also be repaired using the same techniques and then re-nitrided. I also think heavily grooved or damaged irons can now be repaired using the hard chrome process which would be a permemant, if somewhat pricey repair, and the chromes slickness could lower friction, thus lowering generated heat and improving performance.

Just some random thoughts...

 

good luck with the info

 

Nick d T11.the plasma spraying is done by a local company National Coatings here in Winnipeg and yes the plasma coating is the same that they use to protect the JET Engine Titanium Intake Blades . I figure if its good enough for military as well as Domestic Aircraft engines. I t would be OK for my application too . Ps that was 10 years ago.....FP

 

So has anyone tried the plasma coating? What about the Cermet? Is this a good coating if I use the ceramic seals?

 

Cermet housings 80,000 miles on ceramic seals

https://www.rx7club.com/forum/showth...et#post8136915

 

the Plasma coating is a cermet( Ceramic metal) coating the biggest thing to be carefull how you finish it because any Swarf ,cermet removed by break in can harm your bearings ,so you have to almost finish the coating to the ,point nearly to the RA( rough average) that the Engine gets to with a fully broken in Engine, check out the GM and other internet articles on cermet engines. they came to the same conclusion..............FP

 

Are the application process the same (plasma, cermet)? Who does either?