Scalliwag

would think they would have always used the pattern with the least amount of seal travel.
I would think that the only worry would be using matched sets of housings on a motor.
Since none of the other components matter if I read all of these remarks correctly?

nimrodTT

I think what they did was minimize the travel for each width (6mm, 3mm, 2mm) by changing the shape. The problems would arise when putting 2mm rotors (maybe even if they are cut for 3mm) into a housing that was designed for 3mm seals. The very tips of the rotor is the part that is supposed hit the housing wall; makes sense that if you don't have a moving seal there on that extra .5mm of metal, and you spin it up fast enough there will be a small amount of play that can cause the rotor to be that fraction off from where it should be, and cause it to collide will the housing surface. But that's just my hypothesis. Also, I've never heard of any problems backdating the 3mm into the 6mm housing, so maybe the spec is looser.

drago86

we should figure this out, anyone got a pre 86 new 13b housing and a new 86+ 13b housing they can stack with dowels and run a mictometer across?

Buger

Hi Scalliwag,

I have been following this thread for awhile and I want to wish you the best of luck in your venture. Do you know how chrome-molybdenum alloy plated housings would compare with the liquidmetal that you have chosen?

I read that the renesis is supposed to be coated with chrome-molybdenum which is also made for very high heat, high wear resistance and low friction. Perhaps Mazda hasn't gone with other options because of the cost factor but they have said that two of the only materials that have resisted having "chatter marks" are chrome and molybdenum.

Brian

Scalliwag

I am not familiar with that material. I will have to read up on it.
The chroming process they have used in the past is a VERY thin plating. Since these are new sheet metal inserts when they are working with them it is in their best interest to use a thin electroplating type process.
It is much cheaper because there is almost no tooling wear since it is electricity and chemicals and much less time consuming for that stage of the process.
Thermal sprays require machining (at least in this application) which takes more time and tool wear.
Having said that, my advantage is that I do not have to make the castings and I am only concerned with the one area of the housing when I am done.
Mazda has at least some housings that will not pass QA because of casting or machining problems will increases their cost per unit.
So they are going to go with the least expensive plating that will work. I need a high build coating that will work and by the nature of the type of materials that can be sprayed I can use a material with incredible strength.
As much as this process cost and the type of machinery that it is generally used on because of the cost factor we are good there.
The chatter marks you mention are due to anti-galling properties in the material. I am not sure about the rating on the newest material that Mazda is using, but the older material has a much lower anti-galling resistance (compared to Armacor) which I have found out for myself during the machining process. It is much harder to grind.
But if Mazda makes any claims that this is the only material they have used that will withstand the application it is because it is the only material with can be applied in their current type of process, chroming.

drago86

chrome molybdenum is a term usually applied to chrom - moly steel, but in high performance piston engines, a chrome copression ring with moly oil rings is used because of chromes hardness /heat and wear properties, and molys lubricative properties,.,. do you know if its chromoly steel? or just straight chrom and moly? ( i mix i havnt seen yet whic in no way means it doesnt exist)

Buger

I got the information from the Swiss Mazda Media site. It is also the place where we got the Rx-8 torque curve information.

http://media.mazda.ch/dossiers/Wankel/Wankel%20E.pdf

Some excerpts from the paper:

"The inner surface of the rotor housing consists of a chrome-molybdenum alloy plating".

"Trochoid Surface - the surface against which the rotor moves. It consist of a chrome-molybdenum alloy. Molybdenum is one of the only materials that does not suffer from chatter marks in engine applications".

"Port Liner - Port liners "line" the side exhaust ducts of the new Renesis engine. The basic material of the port liners are made of aluminum titinate, the stoichiometric compound made of aluminum oxide and titanium dioxide. This material is characterized by its low thermal conductivity, extremely low thermal expansion coefficient which makes it very temperature resistant, and it is highly porous. The porosity makes this material very useful in engine construction. Its porosity is a result of the cooling process, during which critical interior tension brings about the creation of microscopic cracks, which partially close again when the material is heated".

Brian

Scalliwag

That document was very interesting and covered a lot of stuff. Thanks for posting that.
I figured out a way to do main and rotor bearings with the armacor. We are going to try a set in Ken's car of I can get all my tooling finished in time.
Ken has a high failure rate mainly on the rear main and rotor bearing.
At the highest polished state the coeffecient of friction will be low enough and it may exceed the babbit material. I had never thought about it but those of you that remember me trying to describe the "feel" of the material after I got the test housing back and polished, the feel of the babbit surface of a new bearing would be pretty close.
I have to make a boring jig that will allow me to bore and hone the bearing back to spec with my mill.
I have a cutter to restore the oil recess as well.
So we are going to be testing this as well as long as I can get the jig ready in time. So there is something else to look forward to.

krwright

I just got finished reading the entire thread. Got the link from the SA22C list.
Very exciting stuff! The best part is that I'm located in D/FW (Euless) myself, so Scalliwag is local! Just so happens that I have a 12A that ate an apex seal...
RE: mixing of early and late rotors and housings, I found the following at Mazdatrix's site, regarding GSL-SE engines:
"Note: The 89-92 higher compression / lighter rotors can easily be installed in the 84-85 "C" level (and above) engines. Extra cost is the price differential between the two pairs of rotors, + cost differential of the 2mm vs. 3mm rotor kits, + front and rear counterweights"
(http://www.mazdatrix.com/engnumse.htm)
So I would imagine that you shouldn't have to change your setup for at least all 6-port 13Bs.
Also, at http://www.mazdatrix.com/eng13bsp.htm , which talks about 13B 4-ports to fit 12A RX-7s, they state that the 13B 4-port is "...street ported 79-85 12A cast iron side housings, street ported 76-78 13B rotor housings, and either 84-85 GSLSE or 89-92 Non-turbo rotors. "
So, you should be OK with early 13B housings as well!
Good luck, and I look forward to hearing the results of testing!

Scalliwag

A lot of the racers are using the early 13b rotor housings because the later 4 port side housings are harder to find. It sucks that they changed the grooves over to the side plates on the later motors.
It would be nice if there was a practical way to machine the o-ring grooves onto the later housings.
Yep, you are only 10 miles or so away. So you could come see this first hand and could get in early on for testing purposes after I am comfortable with the first phase of testing if you wanted to.
I don't want anyone that is not local enough to where I would not be able to monitor the build and progress or someone that is not ready to put the motor together soon after the housings are ready.
I have had PM's from two people wanting to test a set but they are too far away.
Ken makes for a perfect first run I think and my my stock motor will be right on it's heels. I still have to get a gasket set, apex seals, springs, corner seals, bearings, etc. for mine though. Plus I have to pay to get Ken's housings sprayed. So I have to line up a lot of duck$ in a row to do all of this.
Ken has had the flu for a week and I talked to him yesterday and he is supposed to try to get an answer on the factory p ports mention in the earlier posts. If he can't use those he is going to take a old set of housings a p port them the same as his current motor.
I am really wanting the factory pports though!

banzaitoyota

Sounds good so har, I have a set of housings waiting as soon as you figure out pricing John

drago86

the coating wont help the bearing failers, its cus the shaft is flexing, making contact with the bearings and spinning hem, he should get a guru shaft, more oil pressure, run looser bearing clearences (taper e-shaft) screw lock bearings, / and or lighter rotors all of thoose will help, soem are just more expencive then others

drago86

I cant wait to see this work,.. no more new housings EVER!, we could all buy junkyard and turn em into brand new ones,..

Scalliwag

I found some pictures from SevenStock5 of some really trick *** looking rotor housings. I did some cropping to keep the pics small.

Maxthe7man

I've a set of housings for you as well when you get it figured out...No one will touch that kinda of coating/machining here with a ten foot pole, so I hope you make headway on this...Max

Scalliwag

What part of "Uranus" do you live?

Maxthe7man

Right near the top of the crack......
Check your Pm's..Max

Scalliwag

Damn, that put's me right around the hole then! That really stinks! (You're in Canada and I'm in Texas for those scratching their heads on that comment)

Manolis_D

iTrader: (2)

Common, updates!!

Heheh, we're all excited about this!

-Manolis

Scalliwag

I wish I had an update. It looks like I am going to have to call Ken and see where were are at with the housings we will be using. I am ready at my end.
If he cannot get the Mazda factory pports soon I am going to press him on going ahead with a fabbed set.
If I go it alone on the first set I will be out more money, but even more of a loss is that I won't have an engine dyno and the instant credibility that Ken and his "friends" will have.
I am chompin' at the bit here because I am ready to roll with this.

Manolis_D

iTrader: (2)

Ah, ok, didn't mean to bug you

Let us know when he comes through with that, very cool

Thanks,
Manolis

Scalliwag

Well good news and bad news, The bad news is that Ken could not get the factory peripheral ports. I did not get the specific reason as to why but I did find out it is Pineapple racing that owns them.
So we decided that we are going to build a set just like the ones he runs in his race car. I went to his house today and got measurements off one of the motors he has torn down.
So I will be cutting a test housing to put pport sleeves in. I may as well post pics of that since it has been some time since we have had any pics on the thread.
So at least I know what has to be done now so I will be busy at it.

Scalliwag

I had put another thread hoping to get ideas on boring the 2" (actually they need to be 2 1/4") holes to make pports. Of course nobody responded to help a brutha out and my impatience forced me to try to figure it out on my own.
Anyone that has been around any mills knows that the tooling is expensive as hell and I know just enough to be dangerous. I did not want to waste money on some fancy *** indexable cutter only to find out it would not work.
Somebody posted to use a drill bit. I'm thinking this guy did not read what I was doing or he would not have been aluding to trying a 2" drill bit surely.
But it did get me to thinking that a bi-metal hole saw just may work. So I gave it a shot. I posted the results on the other thread which is a little weird. I ended up answering my own question on that thread but I figure that there may be some lurkers looking for the answer themselves. The next post is a duplicate of the one on the other thread.

Scalliwag

Actually a hole saw seems to work pretty well. The only bi-metal one I could find in my garage was just 7/8" but I was looking more for how the teeth cut the material more than the size since it is all relative.
Just in case any of you want to try this. I will not go into setting up the lathe jig so this is after the housing is mounted in position to bore.
Since the hole saw used a 1/4" pilot bit I used a bare bit and drilled a 1/4" hole the entire way through.
Most of you can figure out that if you get a hole saw on an uneven surface that it is going to try to "walk" on you and leave a pretty rough looking hole. Since the surface where the bit enters the housing is awkward this is how I kept it from walking.
I took the 1/4" drill bit out of the hole saw and put a smooth piece of 1/4" round stainless rod in its place.
This forced the saw to stay true to the pilot hole. If I would have left the drillbit in it would have had a tendency to side cut the hole. Since the side of the rod was smooth it could not cut change the shape of the original pilot hole.
I know that is a long explanation but it is real important that anyone who tries this method adhere to that step. Otherwise you might end up with a oval hole.

I am milling a set for Ken Sheepers. This port is based on what he currently uses which is very similar to factory peripheral ports as opposed to the Racing Beat that comes in at a different angle than what he is wanting. He has ran both types and prefers this from experience.
Just in case you have not looked at a housing in a while remember where I drilled this is a little below center of an existing hole. The second picture from the bottom would appear to be screwed up if you don't keep that in mind.
I will post a pic after I do an actual pport ready housing and if I run into any surprises. So far this is a pretty inexpensive way to tool up for a job

Scalliwag

Success! (at least getting the bore ready for the port tube)