TehMonkay

iTrader: (-1)

Felix Wankel: I want to build a more simple efficient engine that runs on triangles

Everyone: **** that piston engines work fine

That would've been great right?

Totally dont do it, just buy new housings, dont waste your time, nothing will ever come of it.

Why in the hell is everyone on this damn board such a pessimistic *******?

Black91n/a

Effort >> Reward.

Seriously, it'd be a better use of your time to get a part time job and just buy a new housing, and it'll probably be better. I'm all for experimenting, designing and building cool stuff and all, but this just seems like a recipe for disaster as there's so many things that can go wrong. What are you going to do about the exhaust ports and the spart plug holes that are 90 degrees to the housing? What about the exhaust sleeves? What about creating the necessary draft in order to be able to remove the housing from the mould? How are you going to compensate for shrinkage?

Juiceh

iTrader: (4)

Do it! If you have the tools and some PHD's to help you out I say get moving. You may not ever be able to try this again.


RB does not make rotor housings. They make a couple side housings.

I agree with Blue TII, cast some side housings and reinforce the dowel areas. Everyone will want some of those!

If you can find a damaged 20b thick intermediate plate, I'd say try to cast some of those! Thats a gold mine.

phoenix7

i'm subscribed so just keep on posting.

Kenku

I just have to agree; do a bit more research on the housings. Cut one of your dead ones up. The interior isn't TiN'd.

If you look at the stock ones, the wear surface is a piece of sheetmetal, which is actually serrated on the outside part to bond to the aluminum. This piece of sheetmetal is put around a mandrel, welded into a continuous loop, and the interior part is surface ground prior to hard chroming.

Leaving that aside, if you are inexperienced to the point of trying to figure out sand recipies and not being able to figure out some of the undercut features in the stock housings... I'm sorta skeptical of your ability to produce defect-free castings.

Feel free to try and all, but...

DarkKnightFC

This is the most rediculous idea I've ever heard of. I'm going to make new housings, spend countless hours on this and that and still not have anything close to usable. YOU DONT HAVE TO REUSE YOUR HOUSINGS. If you honestly have the access to the thermally sprayed coatings as you say then why would you not spend a couple hundred bucks MAX on some worn out but not gouged out housings and recoat them. You're going to make your own housings because you don't have the money to buy a JSPEC ENGINE??? Did you even read what you wrote. I can't believe you've gotten this many replies and even more surprised that half of them are positive. You could use that equipment for something far more productive that wasting a bunch of aluminum for the final product to be completely non functional. How were you going to line up the water passages? And machine them to fit the correct coolant seals and dowels? I can't even believe I actually told you what I thought. Because its obvious that you're going to give it a go anyway. Make new housings.....WOW

Box_Man

That was the dumbest thing I have ever read. Did YOU read the thread? The trashed housings have 1mm+ deep gouges in them, and he doesn't want to coat them for fear of the coating becoming too brittle, and beyond a certain point you go past the stainless steel insert and into the aluminum.

Also, the part about the coolant passages, coolant seal grooves, and dowel pins, what the **** man? What do you not understand about CNC fabrication? You can take 13B housings and mill them down to fit 12As, and re-cut the grooves into the housings. It can, and has been done, but even then it doesn't matter for oblio, because on 13Bs, the coolant seals are located in the Irons.

nitronatefc

iTrader: (2)

I'm definitely with BLUE TII on this one. Redo the plates in aluminum with a stock or street port. Have you seen the price of the RB ones? You could buy a damn 20B for that much, not to mention the additional cost of custom parts for a p-port setup. Unfortunately this would require making three different molds. You actually should just make that thick 20B center plate. You would be the most popular guy on the forum for sure.

At least make an aluminum version of a non-aluminum oem part. Think about it...... You make a few to sell. Your cost is nothing beyond the loss of sleep (and you shouldn't be sleeping during the college years anyway). Then you can offer something different to yourself and the rotary community, not to mention you will make some money. Now you can buy some BRAND NEW MAZDA OEM ALUMINUM ROTOR HOUSINGS. Wouldn't that feel more rewarding???

DarkKnightFC

Perhaps I should have highlighted and underlined the part where I said YOU DON'T HAVE TO REUSE YOUR HOUSINGS, PICK UP A CHEAP SET OF USED ONES THAT ARE NOT GOUGED OUT

rotaryinspired

iTrader: (3)

Sounds like tuning or builder error. Might try a stand alone instead of a rteck. Good luck. HOpe it works out.

RX-Heven

iTrader: (1)

Forget about replicating your own rotor housings. No one would want them.
However, if you did all of the side housings with the recommendations made by Blue TII, you may actually have a market for those making it worth your time and effort.

You may even want to do the thick intermediate housing from the 20b. I know I'd be interested in something like that.

TonyD89

iTrader: (10)

I also work in manufacturing. The factory rotor housings are die-cast aluminum alloy. They insert a steel liner into the die before the die-casting process. The die cores the water passages. Other holes (like spark plug) are later finish machined. After machining they are then chrome plated (on the apex seal surface) using a proprietary process that exceeds that of standard chrome plating. If RETed is right and the liner is stainless then I am wrong in my assumption they were just a ferritic steel, possibly an alloy like 4140. They are magnetic which leads me to believe so. Look closely at your housings and you will see the serrations on the insert to help it grip into the aluminum.

I hope this helps but I will have to say you are probably better off buying them. Used if you're on a budget.

phoenix7

I really don't think they are stainless steel. I will have to side with you on this one. I recall reading something that said this was to reduce the time in the hardening bath but I can't recall the exact reason. I'll have to go find my books and see if I can find it.

Box_Man

CALM DOWN! Jesus Christ, I never said it was a bad idea. He wants to do it as a learning experience, and maybe get some usable parts out of it... Or maybe he should say "**** it" and learn nothing, then be an ignorant asshat to people on forums for the rest of his life because "he knows better than to waste his time."

DarkKnightFC

HAHA. I like the way you said that, "Learning experience", "Maybe get some usable parts out of it"

I suggested an idea to use his resources and learn how to do something that would benefit himself and us. And not have to devote COUNTLESS hours to his learning experience. Mind telling me what he would be learning, that he shouldn't be learning already? How to use the machines??? No one is wasting their time here but you bud. The problem doesn't lie in the housings. You have to look at the reason of the failure and things leading up to that. FAR FAR better of a learning experience than playing with some neat machines because you have them for free. Especially if you plan on owning a rotary for any amount of time, and obviously he's not rich to pay someone else to figure out his problems and work on his car for him.

FrankV702

iTrader: (14)

Last time I checked, Rotor housings were made, they werent sent down from heaven. Why wouldnt this guy be able to give it a shot in making them? Its people such as himself why new inventions are brought out, because they have the motivation to want to experiment with things. Im sure when the person that invented a plane told people, "Im trying to build something thats going to fly around in the sky and carry people around in it like a giant bird." he had a lot of people discouraging him and saying "it cant be done" "its a stupid idea" "dont waste your time". Guess what? We now have planes! Point is, if you want to give it a shot, give it a shot. Theres nothing to lose and everything to gain. Even if its new techniques on how to use the machinery. Good luck!

OOh and BTW, if you did the thicker 20b intermediate housing successfully, you can make a lil bit of $$

Kenku

Uh... y'know, all you people going on about the pioneering aspects of this kinda thing? Not so much. It's trying to duplicate something that's mass produced, and do it for cheaper. If you've studied economics, or the results of people trying to do so, it doesn't make sense on any basis but a desire to tinker with ****.

Mazda (or adapted, or borrowed) the specific developments used to make the housings last (the SIP layers) and they used modern die-casting techniques that have been developed on a large scale and subject to decades of trial and error. The OP not only doesn't have the experience of a major manufacturer at doing accurate castings, but from the sounds of it he doesn't have any experience *at all* of doing castings, nor does he have access to detailed information on what led to the designs being the way they are.

In theory, it's perfectly possible to come up with useable, good quality sandcastings, but there's a lot of potential things to go wrong with sandcastings that can only really be learned with experience... and the fact that it's a load-bearing casting is even worse. Work your way up to it, try doing some lost-foam castings for an intake manifold or something.

Oh, and for all the people talking about Wankel and the rest... do you think he just suddenly went "hey, I know, I'll make this revolutionary new engine!" without knowing how normal engines worked, how their sealing systems worked, and experience at how they went and solved various issues? Nope, and even then it didn't happen overnight. The Wright brothers didn't just suddenly make an airplane, they spent decades doing experiments on facets of it to figure out how it worked.

Black91n/a

I never said it couldn't be done, I'm just saying it's a waste of time. Mazda had a team of engineers and millions of dollars at their disposal when they develloped them over the span of years with many of hours of testing and tons of road miles. What makes anyone think that one person with limited resources could make anything even half as good in a few months. There's tons of issues to work out and it'll be easy to screw up on any one of them making it a piece of garbage and a total waste of time.

Even at minimum wage it makes more sense to spend that time working and just buy a new housing.

Innovation is good, but we're talking about re-inventing the wheel here, and that's just dumb.

monkhommey

dont take this personally(its directed towards every one who is so negative) but.. thats ******* retarded ^^^

i take it that your not an engineering student... where he is. i am also. and projects like these offer a profound amount of insight into solving complex engineering problems even if it is a failure.

lets see.. he could either learn how to flip burgers at $5.50 an hour.. OR.... gain more experience in creating a sand mold, designing a mold to produce fewer defects, understanding the effects of material shrinkage during the cooling process, understand the effects of material cooling rates and how to design a mold to take advantage of them, how to create a product from raw material to a machined finished product.. if you like i can continue with many,many more benifiets

seriously wtf??

when all you people started working on your cars... do you think that it would have been a better idea to "get a min. wage job" and pay someone to do it for you?? NOPE. you chose to do it yourself.. and by that you gain a very valuble amount of knowlege.

now i personally think that if you start this process you will most likely fail to create a quality usable part. but its not impossible. i really hope however that you do try. i have my own ambitous project im planning... but im going a different route then you... im not going to post it on the forum untill after i have a result..

CrackHeadMel

iTrader: (2)

haha no no, not right at all.

Black91n/a

Actually I'm a 4th year Mechanical Engineering student set to graduate in 5 months, but I see that there's little point in re-inventing the wheel. I see that it could be a great learning experience, but in the end there likely won't be a useable part, and even if there is it's not likely to last one tenth as long as the Mazda part. It'll probably have cost a lot more in the end as well since you're paying for all the R&D and there's no ecconomies of scale. One area that is being worked on commercially and that I see as having great potential is the repair and re-coating of old housings. That is where I think the future is, not in simply making more.

Your stretch of my comments to taking it to the mechanic doesn't really hold, they just bolt stuff on and off, they don't design and build the parts.

I've built parts for my car, but so far they've been much simpler. I've also done a lot of work on it myself, only taking it to a mechanic once in 5 years of ownership when a rear wheel bearing failed in the middle of winter (besides, I don't have a press). In the future I'm planning on building more parts and doing more costom mods, some of the ones I have in mind I've never seen documented on the forums and I plan on doing just that, but it stops short of casting my own engine parts. Some of that will be stuff that I haven't seen sold anywhere, other stuff is a cheaper/easier home made modification to solve a particular problem.

Bluem

if you have access to a vacuum casting facility-

A-356 t-6 alloy vacuum casted side/intermediate with a Nikasil face would be nice and Nikasil on rotor housings would be nice too.

maybe a press fit lining in the rotor housing so if it wears out or apex seal damage it you just replace the lining ,like you would replace a sleeve in a reciprocating engine.

texFCturboII

iTrader: (17)

Man.... I'm glad that Engineers have no imagination anymore.... leaves more work for us Architects!

Kenku

Speaking as an engineer... look, seriously, wtf? He's trying to save money by recreating a stock part, without a very indepth knowledge of how the stock part is made, and it's not going to happen. I full well support the idea of trying to gain knowledge in casting, but why not do something that has the slightest ******* possibility of turning out a usable part? He doesn't have the facilities to do anything more than a hackjob, even assuming everything works perfectly; the sheetmetal inserts, precision grinding, and hard chrome plating is beyond what a university setting can do. And it's awfully hard to gauge one's progress if, even a perfectly dimensioned part won't work.

And fine, if the OP wants to learn casting techniques, that's all well and good, but why not work on something that stands a chance of success? Intake manifold perhaps; the stock pieces are distinctly sub-optimal and it's complicated enough to learn problems and solutions without being impossible. No sheet metal inserts, no need for tolerating wear.

But the OP stated this was to try to save money instead of buying stock parts, and that's just not going to happen.

phoenix7

I lost track of the thread. DId he make progress?