Scalliwag

6 months back before I even knew about this forum I started a project to try to salvage worn rotor housings. Those freaking corner seals had made my life miserable a few too many times. That feeling you get right when you are about to split a motor only to find problems. Then just have let the "mourning" process run it's course.

I knew that going into this that the first hurdle would be to be able to have a controlled milling process that would not compromise the shape of the seal surface of the housing. I came up with an idea that required many trips to the local machine shop, bearing shop, etc. and built a machine to do it.
Since then I heard that there were some people talking about some people that already do this and ceramic coat the housings. I have yet to hear who they are or how much.
Anyway after kicking a couple of K into this project and tons of headache working bugs out already it is not like I am ready to throw in the towel on this adventure.

I have talked with people who do plating that tell me that they are concerned if metals are used that do not have the same expansion rate as the base metal that I will have trouble. There is also a problem with the thickness of the plating because most processes would not go down even with a few passes.
I just heard about Cerafuse that uses a process that fuses the ceramic to the base metal but I have to find out what they charge.
I have also thought about using a plasma spray process using material equal to the base metal of the housings and then truing the housing on the miller and micropolishing it back to spec.
Then sending them off to a cryogenics facility to let them harden them.

Here is the problem I am having. It seems like the platers don't know anything about cryogenics and the cryogenics people really don't know much about plating and there seems to no one source that can give first hand advice with knowledge from all processes.

I am sure there are at least a few hardcore guys out there that have dealt with all of these processes and how they apply to engines.. any of you guys out there? I have a set of ground housings ready to go somewhere.

rxtasy3

iTrader: (2)

I don't know of anyone that has had that surface of the rotor housings replated. Even if u could find a way to get it done, I think u'd find out that it'd be alot cheaper just to buy new ones.

Scalliwag

For what I got into the equipment now I could have bought more new housings than I would ever use. But I am hoping in the end to be able to make housings that are better than new for much less than the $450 each that new ones cost.
When you factor in the time and money people put in to making peripheral ports, or hours and hours polishing them for show only to have them become scrap metal it is easy to tell there would be a market to repair them.

Just in my rotary head friends alone I have about 15 sets lined up to do. Let's say we all go out and buy new sets at the $900 per pair, that's $13,500.
Hell, I would be happy if I could at least make a better housing for that price. I have even bigger asperations that I can get them out the door for less though.

Fortunately I love a challenge because I definately have my work cut out for me. It's a damn good thing that I have a good day job too to pay for this **** too!

Here's a pic of mine, but I want to build a rotary T-bucket once I get this project out of the way.

duchi

sounds like a great idea. i'm sorry that i don't know of any resources that would help ya but good luck with your project.

MSpeedRX

we had a few sets re-chromed by an electroplater - first few didnt seal that well - compressions down and the hard chrome never bedded to the apex seals. Then tried some which we honed by hand with a stone and they worked ok after a decent running in period. I don`t think the work and end cost was worth it unfortunately - would need someone to get a better finish on the housing surface to consider using in a boosted engine.

Scalliwag

I don't have any trouble with the finishing. My polish process works great. It is a long way from Australia to Texas though. Hell, the water don't even spin the same direction going down the drain!
Did any of the housing have corner seal wear before you got started? Did the plating take care of it? I am very interested in details if you have time to cover your experience as far as what you started out with and how thick they plated it.

fdracer

i think your biggest problem is clearances. you're gonna need clearance exacted to the mm to get good sealing. to get it replated and ceramic coated you have calculate for the exact thickness of the chrome and the layer of ceramic on top of it and mill the housing to accomodate them. imo, it would be very difficult to get such exacting standards. lastly, whatever you do, do not get the housings cryogenically treated!

Scalliwag

Getting the housing to an exact original spec is not a problem. The controlled machine process is brings the wall surface to spec even if a coating is inconsistant. As long as the coating is not below spec on any part of the surface. Why would you not have the housings cryo treated?

fdracer

cryo treating makes the parts stronger but very ******* brittle. cryo treated parts will crack eventually, more often sooner than later. my engine builder learned that the hard way, he lost $40k worth of cryo treated parts.

Scalliwag

I wonder if they were not done correctly. There sure is a lot of hoopla going around about all the really hardcore race teams running cryo'd parts.

SPOautos

Interestingly enough there is a post about 10-15 down from this one that has info in it about redoing a housing. If you go to this link and scroll down about 1/2 down the page you'll find the info........

https://www.rx7club.com/forum/showth...hreadid=102831

I'd really like it if you sent a set there and let us all know how it turn out

STEPHEN

Scalliwag

It sounds like these people are doing the same thing I am attempting. It is probably the same people that I heard rumored about after I was already pretty far into this.
Does anyone know the Rockwell hardness on a fresh housing? I took a set to a shop at lunch today that use plasma arc spray process. They quoted me for:
Kanthal- 23 Rc
420 stainless- 45 Rc
Armacor- 55 Rc
Chrome Oxide 55 RC

Chrome Oxide is ceramic and it was not cheap at all. The Armacor was about 3/4 the price. I went to the Armacor website and they claim, well read it for yourself
http://coatings.liquidmetal.com/inde...ion=technology
I am not sure about stainless or the Kanthal. When I went to a site to find out the specs on it I found that they have several variations of the material. They are at http://www.kanthal.com/
From what I can tell Stephen the only information on that thread that they gave you was a copy of an email with a name and PO box.
I would think that as many people that hit this forum that someone would know more about them.
Either way I am into this far enough that I need to make my own process at this point. I have a long way to go before I can do these for other people.
But I still want and appreciate input. I'm not spending money I can't afford to lose knowing their is a risk. But I knew going into it that it would take some perserverance or everybody would already be doing it.

That shop wants some "guinea pig" rotors so I am taking some 12a's over the weekend and prepping them. That way they can get a feel for the material. They want the nitrite off and they said that the more scored the surface the better. That is great because I can rip through it faster and not worry about smoothing. I will take pictures at the different stages for you guys to check out.

fdracer

scalliwag, how much is this **** gonna be per housing?

Scalliwag

I have to find a way that works and see how much goes into it. Right now with the numbers I just got from one shop it would not be nearly as low as I am wanting them to be. If I cannot make a BETTER than stock housing available for less than $400.00 it will not be worth it. If I can do a ceramic that will take some punishment for $500 I would be happy. I would have to have cores as well or process housings that people send me.
It is kind of hard to put a price on a yet to be finished
product though. I would love to know what the "other" guys are charging. Maybe they will see this and chime in.

Felix Wankel

You need some housings like mine then

<---------------

Scalliwag

Haha!!! I have some nasty little 12a's that will be great for the testing. But those look pretty nasty for sure!

turbostreetfighter

scalli, i am in houston and have instant acces to a full facility of CNC mills and lathes and even know of some wire EDM shops too! and i can use Virtual Gibbs and Edge cam software. i also have some intersting ideas on the subject but it would take quantities to get the price down. you are right about not wanting to redo housings ....i CNC ported my exhaust ports and had them ceramic coated it would be a BITCH if i had to redo them!email me at wwm1@wt.net

Scalliwag

That wire EDM is some cool ****. I think you would probably be shocked at how well I can do the milling and polishing process though. I would love to have access to the equipment you mention but that is one of the reasons a big shop has to charge so much. The only thing the machines I built will do is mill and polish housings. It is the coating that has me more worried right now... at least the cost of getting it done.

I would love to have access to a tool and die shop to make a mold for aluminum side housings. Then a foundry to make them. Do you have any hookups for that project?

turbostreetfighter

yes i do, but i am sure you already know ....that **** aint cheap!!


MWW

Scalliwag

Yep I know. Hopefully I can get this housing project wrapped up and take the proceeds from it and cutting rotor slots to 3mm and put the extra toward that later on. Fortunately the 3mm project was straight forward and the only hurdle there was getting the horizontal mill. At least the mill will do more than cut rotors. I just haven't found anything else to do with it yet. My garage looks like a freaking machine shop because all these machines are TOO damn big! At least that is the way my wife sees it!

rxtasy3

iTrader: (2)

I used to work in tool and die repair. Did repair and maintenance in house for an aluminum and zinc diecasting company. They don't have a machine big enough to make something that size.

Scalliwag

Boy it would sure be nice to have access (and the knowledge it takes to run) all the equipment for all the big dreams!
Hopefully after I deliver the 12a housings I can get some answers quickly. Once I get something that looks promising I will take some really tight pics.

So does anyone know the rockwell hardness of the seal surface on a new housing?

javrosario

iTrader: (5)

Hrm, i thought Racing beat sold Aluminum side housings already? Just a thought. Also another thing is about reusing old housings, is the shape of them. On old high of mileage housings, the aluminum part of the rotor housing , the water passages are not really in good shape. Also have to worry about checking the housing to make sure they are not warped.

machinehead

What about cracks... you know, where the spark plug holes are? Is that something that would also be repaired with a new surface? If so I will have 2 in a few days because I just found out mine are cracked right there! If you ever get this going I am going to have a whole stack of damaged housings for you.

Scalliwag

Yep, RB does sell aluminum side housings, for $1250 each. I think they need a little competition to get that price a little better.
All that has to be considered. Not every housing is going to be a good candadate for resufacing... they'll just make a good clock Anyone who sends housings to me will need to check some things out before they send them.

By the way, I got a set ready to be plated today. I am crossing my fingers that the shop decides they can do them cheaper than the original quote once they run a pair and see how easy/hard they are to work with.
Keep your fingers crossed guys.