Scalliwag

I have an opportunity now to by a used setup for 25% of the cost of a new one. The unit is in almost new condition. That does not include a lot of other things I have to buy as well to be setup to use it. A really serious air compressor and a grit blaster will be needed and enough smaller items to make up a good piece of pocket change. Also the rolls of wire for spraying have to be bought.
It really came down to this though: If there is a failure it will be due to application and/or material choice. Every person I talked to was a specialist at some level in the field and agreed that if I was spraying any type of metal surface being used for any type of use that there would be many different products that would exceed any type of plated or non-plated surface.
Anything such as hard chrome is so inferior to the spray wire process that it will be up to doing it right.

The one question that came up from one of the specialist was that he was very sure that it would work, but was I sure that there would be a market for the housings. All of his doubts were that I would have to do a pretty good shitload of these just to make up for my setup cost.
I think that part is just the risk of business. If I can get setup I can ride out whatever time it takes to make my money back. Like I said early on that it is good thing I got a good day job (especially with this economy, and I work in the defense industry) There are enough local rotary guys around Dallas/Fort Worth if I cut them a good enough deal to help me out being guinea pigs too.

If you actually felt the surface of the first housing you would be blown away by it. When you run a screwdriver blade across it and a stock housing like you are trying to gouge the surface there is a huge difference.
I will be able to do side housings and with the lower coefficient of drag there the side seals "should" last at least 4 times as long.

So my risk lies in how long before my R&D is done with and I can make the loan payments if I never sell one set. Of course my wife better never hear me say that!

steell

I subscribed to this thread at the beginning, and have been following your posts with great interest. If I recall correctly, I read recently that Mazda was going to increase the price of the housings by 50% or so. That would make it about $600 each. If you can repair and coat damaged/worn out housings for $300 or less, I think you will have more work than you can handle.
You need some way to test and document the durability of coated housings, something like 100k miles/2000 hours, with no issues. I really hope you succeed in this project.

Steve

Rx7carl

Scalliwag, I've used aluminum brightener from napa on aluminum wheels, it works wonderful. Spray on, count to 10, hose off. Dirt, brake dust, grease, all gone and the wheels are nice and shiny. I can spray dpwn an old rotor housing today and post b4 and after pics for ya.

Scalliwag

Staying under $300.00 is not a problem. The really cool thing is that if someone breaks an Apex seal on one that has already been coated it will be even less to repair it. I base that on the fact that touch up does not require as much time or material and because of the metallic structure the touch up is as good as a full rework. So if you did have the bad luck of breaking an apex seal later on you would not be in the bad of shape for getting the housing fixed.

While testing an engine for 100,000 miles would be great it is not practical for the short term. At some point during the testing I have to flip a coin. But I don't flip coins on other peoples dimes so I would have to warranty the work. If there are going to be any problems I will find out early on. Because of the bonding strength, hardness, coefficient of friction, and temperature ratings exceed the stock surface I am really confident. Most of the people I spoke with had no reason not to give me an honest answer since they did not have any stake in the project. All of them are eager to see the results too, or at least they said they wanted me to get back with them and keep them posted on my progress. None of them know **** about a rotary though.
The reason I included temperature in the rating is because hard chrome will not withstand the temperature for boiler tubes that the Armacor is on. The reality of the temperature rating came down more to that. Basically the rotor has hard chrome on the side plates and I forgot what is on the sheet metal insert, but neither would hold up in a boiler tube. I know that may not be a scientific way of determining, but it is a process of elimination. (hehe!)

Scalliwag

That would be pretty cool. It would be nice to know what chemicals are in it. If it works I will pick some up.
Thanks!

Scalliwag

Oh, and because the substrate is supposed to be kept as cool as possible warping is not a problem. That is an advantage to arc spray as opposed to flame spray and other processes.
There are a few other things I came across but I really cannot remember everything that has already been covered. I think we are just wanting to get a motor fired up, ran a while an ripped apart. I plan on some video as well so I hope most of you have high-speed access.

Rx7carl

Sorry Scalliwag, it didnt work well at all on the housing . Seems to work well only on soft aluminum alloys, and pure aluminum. It didnt do anything to the housing. BTW it has sulfuric acid, hydoflouric acid, and Glycol ether. It's nasty stuff.

Scalliwag

Yep, if it is acid based that is pretty nasty but very effective. It would probably have to be a stronger solution for our alloy.
Butyl based solvents work really well for degreasing I have found. There are some trade names like "Mean Green" and others out there. For some reason the chemical industry got off on the color green. The color is actually a dye though. It has kind of a soap smell to it and can be dilluted with water.
There are more powerful degreasers out there but all I have seen are solvent based.
The brightening is another story. I have not found a way other than polishing to get the results I want there. Acid based cleaners tend to make our alloy a dull gray color.
There are vat type machines called "tumblers" that use everything from walnut shells to crushed ceramics and other media. You put the part in and usually you hook a wire or something to keep the part from going all the way down to the bottom. It can be a bitch to pull the parts back up and I don't think the cleaning effect works as well either.
What happens is all this media is vibrated in a tumbling motion over the part.
The trick on that would be finding the best media to give a semi-polished effect. You also have to turn the part at least a couple of times. The equipment is expensive as hell and I could not justify it right now at least.
There may be other processes that may work better anyway.
Even blast cabinets work well for a semi-polished look. Unless you have several blast cabinets I would not go that route though.
You want to start with a more aggressive media sometimes to start with and work your way down to a finer media for finishing. I hate changing out my media in my blast cabinet and then you have to change the tip sometimes as well.

I need to find a place that makes metal stamps and get one that says "Scalliwag". I made a jig that lays over the 13b on the rotor housing that I use to grind off the "13b". I want to use my stamp on them for A: advertising and B: know a housing I did when I see it.
So if you get any ideas as to a place that may make custom metal stamps let me know.

Rx7carl

Are you going to be doing 12A housings as well? This thread has been goin on so long that I forget.

Scalliwag

I can do them just as easily. So it depends on what people want to send me. I am figuring on people sending their housings for me to do. They need to check for warpage, cracks, etc. before they send them. If I saw a problem I would let them know.
I will probably do some that I sell straight up and have a core charge that is refundable after I get a rebuidable core.

nimrodTT

How about acid dipping to clean the housings?

Keep in mind that Mazda slightly changed the eccentricity for some of the housings so you might need to tweak your machine to account for it when changing between say 13B and 12A.

You know that this recoating process is going to put you in a prime position to become an engine builder. Have you considered it?

How I envy you, you're on the ground floor to change the 'face' of the rotary and you get to do all the R&D yourself. What are you going to call your new business?

Scalliwag

I could change the shape if neccesary by laying out a stock pattern. I have not played with a 12a on it before to see what you are specifically reffering too, but I did account for changes just in case some weird **** ever came my way or somehing bizarre like someone wanting to oversize or undersize for whatever reason.

As far as being a builder I have no desire for that. Way too much headache and so many more variables. At least when I deliver some freshly finished housings they can be visually inspected as soon as the person receives them.
I have seen cases where builders took undue critisizm because they delivered a good motor but the person that had them build a ported motor did not know how to tune it and blamed them because it ran bad.
At least you can see what you have easier.

Not only that but I am afraid that trying to keep pace with it and my regular job would wear me out and take away much more time from my family.
I am hoping that the engine builders use me to resurface their housings though. The more I can get out the door the happier I will be and I am pretty sure that I could keep up with all the demand on that.
I see the builders, racers, and people that never plan on selling their cars coming to me on this.
Anyone just tossing a motor together and driving it a while and selling it or strapped on cash are going to used worn housings and just hope for the best.

As far as calling the business, it's "Scalliwag Performance". Once I start getting ready to do this for others I will have decals made up that will look pretty good and hopefully they will be stuck on some pretty tight cars. Of course if you pull the hood open and don't see "Scalliwag" stamped where the 13b used to be you know they only have the sticker.

I thought about spraying and polishing some metal strips that were kind of thin and maybe in some form of advertisement to mail for people to look at and feel the material. Once you feel this stuff you will really trip out.
The difference between it and polished steel or chrome is too obvious for anyone with any nerve endings at all not to tell the difference.

As far as acid dipping housings, I tried dilluted muriatic acid and it is very aggressive. The results were not that impressive as is turned the alloy kind of a dark gray.
There are so many different acids to try that there are probably several that would get a better result than what I got though.

Scalliwag

I am thinking about trying out an idea I had on the first set of housings. I have always thought it would really be neat to be able to keep an eye on compression all the time. This idea covers how I think it can be done.
Look at the picture to follow along. The drawing is exaggerated because I am to lazy and lack the talent to do it accurately
Set the housing up on a drill press because several drilling steps would be involved.
Drill a hole about 3/32" between the trailing spark plug and the side of the housing. The hole would be drilled all the way though.
A piece of stainless tube with about a 1/8" i.d. would need to be obtained for the next step. Stainless brake line would be perfect.
You would have to measure the o.d. of the tube to determine the next drill size.
Let's say it turns out 3/16".
You would drill a 3/16" hole though the 3/32" hole stopping 1/8" before going through the inner surface.
The next step would be to drill and tap the outer surface for a fitting to attach the line going to the gauge.
After the fitting is tapped you will be able to determine the length the tube should be cut to. The hole size should so that the tube is press fit snuggly and then epoxied around the water jacket area.
This would be done to both housing and have a separate gauge for each one.
Gauges with needles that are easy to see even when bouncing would be needed.
The idea is not so much to make it very easy to do a standard test as is is to be able to check hot/cold and throughout the Rpm range as well as monitoring changes in compression though the break in cycle.
Video could be made of gauge reading also so that it could be slowed down when viewed later for a better true reading.
I don't know about you guys but I get a damn headache when I am doing a compression test on a rotary. Most of you know that to do these correctly you have to use a compression gauge without a check valve in order to read all three sides of each rotor.
Am I the only one that every does it and get a little messed up as it the needle is bobbing to beat hell?

I know they make special gauges for this, but I don't have one and besides I think that setting it up this way gives a lot more range of use. Not to mention that you could see what goes on when the motor is actually running. To do a normal check you would just pull a fuse to keep the motor from firing.
How does this idea sound?

Rx7carl

I would be worried about keeping the integrity of the water system seal, and combustion chamber sealing due to the different co-efficients of expansion. I'm afaid in this case that would cause the epoxy to crack and seperate from the surface and cause massive leaks. Just my $0.02. I'm not a metalurgist or anything.

Scalliwag

It's not any different than when you make a peripheral port except that since the stainless tube will have such a thin wall that the expansion rate will not matter as long as it is press fit. The nice thing about using a stainless tube it that it could talke a lot of direct force applied to the end of the tube without bending.
I doubt that the epoxy would actually do anything more than make me feel better knowing it is there.
It is the same principle as a freeze plug. A heavy gause sheet metal freeze plug has a different rate of expension than either an aluminum or cast iron block but usually only fail due to freezing or rust.
As you know they seal fine even without the use of epoxy.
It is funny that I make this argument since I use rubber freeze plugsbut for other reasons. Mainly because they go in easy and if you ever have to replace one it it a lot easier than getting a metal one out. All it takes is a wrench and enough room to pop them in. But that's a whole different story.

Rx7carl

Good point. If it was a press fit then rock on!

setzep

I'm assuming you would have a low pressure gauge for compresson tests (200psi) and then switch it out to a higher gauge for when the engine is running (probably in the 1000's??).
Maybe a better thing to have in there than a gauge is a pressure transducer that can read up to 8000psi or so. This way you can see when your engine is knocking. You could also datalog the feedback of the transducer. Most pressure transducers have a 0-5 volt scale (0 volts=0psi and 5 volts would = 8000psi) so if you had a spare input on your Haltech/Electromotive/whatever you could really have some fun with this idea

Scalliwag

I will have to look into that. It is a very interesting idea.

stinkfist

Are you sure about this?

I know that you can use 12a side housings on pre-86, 6 port 13b to build a 4 port motor.

I also have a friend that has REPU rotors in a 13BT motor. (They are higher compression than T2 rotors, but lower compression than N/A rotors)

I know that you can use the REPU rotors in any pre-86 13b.

The only reason that you cannot use the 12a side housings on a 86+ 6 port is because the water jackets do not line up.

I don't think there is any differance in the shape of the rotor housing.

Do you know something I don't?

Not flaming, just curious.

Mike

Scalliwag

That does not sound right to me as far as I understand an trochoid pattern can get bigger or smaller but due to the components (mainly the rotors) maintaining a triangular shape that the suface (of the apex seals)must maintain contact at all three sides at all times.
This should limit changes to the trochoid shape since any change would have an effect on the seal.
Maybe I am wrong but I really do not think so.
I do know though rhat even if it were the case I would be able to maintain the integrity of the original shape of an original housing regardless if their was a change to the overall trochoid shape. That would be the main reason I was not worried about the point being brought up earlier.
As long as I can compensate for size and shape I know all will be good.

Scalliwag

This is cool news here guys. I talked to Ken Scheepers at length today. If you are not familiar with Ken, here is a link. http://www.nhraimport.com/2002/drivers/k_scheepers.html
He bought a Turbo II parts car from me last year but we had not talked since. I had been in contact with a mutual friend that is a crew member of his about talking to him about this. I basically had sent him all of the research we have discussed here and let him know that this was in the testing phase and wanted to know if he was willing to help test.

He wants to do this. He has "a friend" with some Mazda factory peripheral port housings with flaking problems. They can't be used like they are so if the guy will let him we are going to use these. Another cool development is this MAY also lead to access to an engine dyno. Of course I am going to owe some favors on this.
For starters I have to provide the rotors and the e shaft. That is no big deal at all. But the people with the engine dyno and the Mazda digital compression gauge are going to be getting some free resurfacing work done for this favor.
As you would expect though the people with the equipment will have a great amount of interest in this project as well.
This is definately a good deal and Ken wants to have one up and running so it can be ran in March.
He knows that that this is an untested project and he is willing to give it a shot. This is going to put the first motor on hold because he wants to get it done as soon as possible.
One thing for sure is that it puts a lot on the line. He is doing me a bigger favor than I am him. When this works I think the word will get out pretty quickly. I don't want to hear any "what if's" guys!!!
So the stock housings are going to the backshelf until after we get a race motor built.
I will still be taking pictures but I may have to take them from select angles if Ken does not want shots of the port work. People get a little tense about that so you have to make sure you respect that. Hopefully we will have pics on a dyno and scans of the compression readings too.

We will probably know by the end of the week if those factory peripreral ports are going to be the "beta's".

nimrodTT

I've heard it time and time again from places like RB and Mazdatrix. It usually has something to do with the later 13B's (generally 2mm) mixing housings and rotors with earlier 13B's (generally 3mm). From what I gather they changed the peritrochoid shape enough that if you put the later rotors into the earlier housings and spin it high enough the rotor can hit the housing wall. But it's just something I've read about, no first-hand knowledge here. I think Mazda changed the trochoid shape every time they changed the apex seal width. It makes perfect sense to do this, as the seal will travel differently depending on its width.

Scalliwag

I could understand not mixing rotors because of compression factors. But the way the stationary gears and the e shaft control the position of the rotor of the rotor you would have to match e shafts and stationary gears too. At least that is the way it would draw out on paper. The only thing I know about using matched rotating components other than rotors, is the flywheel and counterweight.

nimrodTT

They didn't change the shafts or gears, its just spossed to be the rotor housings. Think about how the seal slides along the surface of the housing, then imagine that seal being twice as thick. Now, as the assembly rotates, different relative parts of the thicker seal would be touching different relative parts on the housing at the same places in the cycle. So to compensate, the shape is changed so that the seals touch the same part of the housing at the same time. Maybe Mazda tried to minimize vertical travel of the seal in order to minimize wear on the spring. Does that make any sense?

drago86

ive heard that too, the shape is *sligtly* differnt, you have to remember that the rotor isnt sized exactly to the size of the housings, theirs play in their for the seals, so you can modify the housings shape and still have the right travel, this would , however mean youd have to modify the rotors too. I think the differance is in the "bump" where the 2 circles of the trochoid meet, not exactly sure though,..