Well, basically, I'm just wondering why people haven't started porting irons with CNC to get more accurite and consistent porting jobs done. Additionally, why take the risk of ruining an iron by a little slip-up of the bit popping out of the port or cutting too deep?



Just morbid curiosity!



https://www.nopistons.com/forums/pub...1047683329.gif

because every housing is different you can't port them all the exact same way

JHB in Canada here is setting up a program to do porting with a CNC machine.

That is really interesting https://www.nopistons.com/forums/pub...DIR#>/wink.png Would that bring porting prices down ? mm....

Good luck.



B

JHB actually already does CNC porting, the ports look decent too.



kevin.

To the people on here who know how to do it. There really isn't much guess work. To those who don't have enough to pay those who know, their price is guesswork.

A shop with a CNC mill around here said they could do it, but the cost and time of the setup just isnt worth it, unless you are an engine builder by trade (or blow up engines on a regular basis https://www.nopistons.com/forums/pub...IR)

[quote name='BDC' date='May 15 2005, 10:29 AM']Good luck.



B


[/quote]



Oh come on lol!!

[quote name='R.P.M.' date='May 16 2005, 12:55 AM']Oh come on lol!!


[/quote]





What? I still agree with BDC. CNC porting for boinger heads is an economical way to get a good port job. But it still has to be smoothed by hand to remove the CNC marks(because its faster than having the CNC machine take out its maching marks). But all the top port jobs are still done by hand. The CNC ports excel in their repeatability, but they are only as good as the person programming them. Ever notice all the race heads for piston engines are hand ported? Even with the prominence of CNC ported heads?

[quote name='falcoms' date='May 15 2005, 08:32 AM']Well, basically, I'm just wondering why people haven't started porting irons with CNC to get more accurite and consistent porting jobs done. Additionally, why take the risk of ruining an iron by a little slip-up of the bit popping out of the port or cutting too deep?



Just morbid curiosity!



https://www.nopistons.com/forums/pub...1047683329.gif


[/quote]





There are some ports being cut with CNC machines.



There are some problems. To gain any benifit you must be feeding that machine around the clock. An auto loading machining center has an overhead that is more than you make. The loan payment, insurance, maintainance, building and floor space rent and so on is the overhead. To do any number of plates you must do a setup and jig construction for each face of the 4 plates.



So you would run all of the front irons, then the front side of the center iron then the rear side of the center iron and last (or any order that makes more sense) the front of the rear iron.



Then you need long production runs (large numbers of parts) in order to keep costs low enough for anyone to afford to buy the service.



So say the shop owner needs 20 pieces of any iron to break even on the overhead before he makes any money. Where will he get that kind of business?



Two nut case motor heads in your office with 2 sets of iron to be one bridgeported and the other street ported is not going to get anything but a smile. This guy needs $4,000.00 a month out of his Milicron to keep it in the building.



But if you can find an old guy with some early paid off machines, he might do it just for laughs. But nothing on a commercial basis.



How many irons will be ported start to finish in the US this month? 100? 200?



If one shop was doing all of them, the overhead deal would be paid for those months, but then what? One reason that machine tool leasing has become more popular, is that overhead deal. You end up doing jobs that make little profit just to make the payments on purchased machines.



It is entirely doable.



Lynn E. Hanover

[quote name='mazdaspeed7' date='May 15 2005, 10:10 PM']What? I still agree with BDC. CNC porting for boinger heads is an economical way to get a good port job. But it still has to be smoothed by hand to remove the CNC marks(because its faster than having the CNC machine take out its maching marks). But all the top port jobs are still done by hand. The CNC ports excel in their repeatability, but they are only as good as the person programming them. Ever notice all the race heads for piston engines are hand ported? Even with the prominence of CNC ported heads?


[/quote]

Bingo.

People need to do their research before making assumptions.

The BEST piston heads are hand finished.

CNC allows for better repeatability, but it's next to impossible to get a "smooth" finish from the mill head tools.





-Ted

[quote name='RETed' date='May 16 2005, 09:31 AM']Bingo.

People need to do their research before making assumptions.

The BEST piston heads are hand finished.

CNC allows for better repeatability, but it's next to impossible to get a "smooth" finish from the mill head tools.

-Ted


[/quote]



IDK, My dad is a machinist by trade and programs and builds precision (1/100 of a micron) grinders and has done mills accurite to 1/10,000 of an inch, so I don't get why it's termed so impossible to do it. You don't need any majorly fancy machines to do it, just a CNC kit bolted on to your basic vertical mill, zero it in, and away you go. You guys are talking like we are going to the extreme that we can't do it without multi-million dollar machinery. It's just not the case.



I bet you a program could be layed out in cad that knows where the seals pass by and you enter what port you want based on that, run one of 3 or 4 programs on each set of irons, with the mill set to zero in on the iron every run before cutting so you can have some error in placement in a vice or something, and do the irons for MAYBE $1k for a bridgeported set. So big deal, you have to place the irons in the mill twice so you can cut one plane (actual port) and then the other (side of iron), for the time saved, it's well worth it and you get a decent profit if you do it as a business. That and you can make your guarantees of power made much more accurite and to tighter tolerances because the port is so repeatable. I mean by hand you can see anywhere up to 50hp difference on a bridgeported engine with the same equipment all around from the same shop, same person, just because the ports are not as repeatable because of sheer human error.



To me CNC would be the best way to go, bar none. I think it's just because rotarys aren't popular enough to warrant using such equipment. Like one person said: How many irons are going to be ported this month? About 100-200 max. Not nearly enough to go super high-tech like some boinger shops are. It sucks IMO, but such is life I guess...

Youre missing the point though. Porting is as much art as science. Do you expect some of the master porters to give up the tricks that make their ports magic so you can try to put it into a CNC machine?



When it really comes down to it, a proficient porter can do a set of housings quicker than you could set it up to be done with a mill and hand finish it(because hand finishing is always required on cnc porting). I can do the rough porting for a streetport on the intake in about 20 minutes with carbide bits and an air die grinder. The time consuming part is the hand finishing.

[quote name='falcoms' date='May 16 2005, 05:32 PM']IDK, My dad is a machinist by trade and programs and builds precision (1/100 of a micron) grinders and has done mills accurite to 1/10,000 of an inch, so I don't get why it's termed so impossible to do it. You don't need any majorly fancy machines to do it, just a CNC kit bolted on to your basic vertical mill, zero it in, and away you go. You guys are talking like we are going to the extreme that we can't do it without multi-million dollar machinery. It's just not the case.





To me CNC would be the best way to go, bar none.


[/quote]





it doesn't matter if the machine is acurate to .00001".... it doesn't NEED to be that acurate. the housings are all different and there ARE casting flaws, varying wall thicknesses, etc... no way the cnc would work except for maybe the port oriface, or cutting bridges, but even then you'd have to zero the machine everytime.



plus, you'd need a 5 axis mill to get into all the spots you need to get into while porting...and even then it still wouldn't be as good as if you did it by hand.

Son, how much CNC Programming have YOU done? How long have YOU been a machinist (Chucking up parts in daddys CNC Machining center does not count). And most importantly, how many housings have you ported?

You guys are all soo mean to this poor guy sticking up for his father's profession.



...so the master porters aren't going to give up their porting secrets...unless you are the people doing this, you won't know either.



I have worked with CNC machines at school (i am an engineering student)and it wouldn't be extremely difficult to make this work effectivly. A buisness that does basic machining of the ports and then hands the irons back and says, now all you have to do is smooth out these machining marks like this..... would be more economical. Bottom line is that the major risk of ruining the side housings from an inexperenced hand piloting a dremel is reduced and there is a potential for the cost to come down on port jobs if a shop already had access to the machinery.



Does anybody know how many side housings are scrapped because a do-it-yourself porter slipped or wasn't sure how far to go etc... I don't know myself but I am sure that this occurs.



The ports might not be as significantly opened as a master porter and his guide of hand, the port job won't nesesarily be a complete purchace that is plug and play, but the potential to have more affordable and consistant port job is increased.



As for the actual machining and individual rotor housings...the irons may/will have defects, but they are created with tolerances and if they did not meet the required tolerances, then mazda would not have put them into the market. Im sure somwhere somebody has or can get the manufacturing tolerances on every part of these engines. And in the worst case senario, new irons can be a pre-requisite if used ones can show significant wear that would be detrimental to the engine's life expectancy.



Also to my knolege, all of the commercial "porters" (persons whom are expert in the art of rotary porting) are located in california or florida...or at least the majority are. A generic Jig could even be marketed on the internet for cheap with generic port specifications/tolerances so that one could go to a local machine shop and have it done there.



"Good" is a subjective word, so saying that it would not be as "good" is a basic opinion. I might go as far as to say that a CNC port job would be "better" than a hand port job because their tolerances are more consistant than a hand port job.



Im not saying that my word is final..but this is my 2 cents.

[quote name='laundryhamperman' date='May 17 2005, 12:22 PM']"Good" is a subjective word, so saying that it would not be as "good" is a basic opinion. I might go as far as to say that a CNC port job would be "better" than a hand port job because their tolerances are more consistant than a hand port job.



Im not saying that my word is final..but this is my 2 cents.


[/quote]



AGAIN: Laundryman PLEASE state your experience? HOw many engines? How much actual machining have you performed. Spouting off a bunch of college textbook crapola doent cut it here.

Machines dont have the human "touch." Porting is every bit as much art as science.



You still need to do the finish work by hand, CNC porting on cylinder heads is for consistent mass removal of material. Porting of rotaries doesnt involve mass removal of material, its more of a fine reworking of the ports. This is why CNC ic impractical for rotaries.

I would agree that machining does not have the human "touch"...and for that reason i give credit to the very skilled people who port these motors and give credit to a hand ported motor over a machine ported one.



Being stubborn and saying that it couldn't be done effectivly is closing doors b4 they can be opened for examination.....saying a rotary won't work b/c piston engines work well is a satire to this point. banzaitoyota...where is your R&D to prove that it won't work? I've backed most of my thoughts where you have simply slammed on the people pro-cnc....or not even pro-cnc, but ppl who simply give the idea credit that it could work under the right conditions.



Again subjectivly...I think that a hand port job would be "better" than a machine port [B]because[B/} a human can better smooth the edges and shape the port to a greater extent allowing greater overall flow and effectiveness of the port job to increase power.



and for your reference...i have well over 100 hours of CAD work (including custom designing for personal interests) and 5 hours or so CNC Mill/Lathe experience as well as a semester working with an automated assembly line. From experence, it doesn't take much to set up this equipment, just the know how to work proficiently. The majority of the time spend is behind the computer and waiting for the machines to complete their job.

[quote name='laundryhamperman' date='May 17 2005, 04:19 PM']I would agree that machining does not have the human "touch"...and for that reason i give credit to the very skilled people who port these motors and give credit to a hand ported motor over a machine ported one.



Being stubborn and saying that it couldn't be done effectivly is closing doors b4 they can be opened for examination.....saying a rotary won't work b/c piston engines work well is a satire to this point. banzaitoyota...where is your R&D to prove that it won't work? I've backed most of my thoughts where you have simply slammed on the people pro-cnc....or not even pro-cnc, but ppl who simply give the idea credit that it could work under the right conditions.



Again subjectivly...I think that a hand port job would be "better" than a machine port [B]because[B/} a human can better smooth the edges and shape the port to a greater extent allowing greater overall flow and effectiveness of the port job to increase power.



and for your reference...i have well over 100 hours of CAD work (including custom designing for personal interests) and 5 hours or so CNC Mill/Lathe experience as well as a semester working with an automated assembly line. From experence, it doesn't take much to set up this equipment, just the know how to work proficiently. The majority of the time spend is behind the computer and waiting for the machines to complete their job.


[/quote]





The vast majority of porting done is streetporting. There is very little material removal on a a streetport. Its almost all detail work and finishing. CNC maching has no place doing finishing work.



Next you have bridgeporting. It could be used to cut the eyebrow, but theres another problem. A CNC machine couldnt make some of the cuts necessary for proper flow. So you would still be left with a great deal of work that has to be done by hand. doing the rough cutting on a bridgeport eyebrow doesnt take very long to do by hand. Bridgeports are still not very common either, so you have an extremely limited market.



With a peripheral port, a CNC mill would be good for doing the rough cut. But that is a very uncommon port, and its almost pointless to consider it for the sake or argument.



Ill agree it could work under the right conditions. Thats why its common on piston engine heads. But with the prevalence of streetports, and the fact that CNC cant hardly do anything with a streetport, rotary porting does not have the conditions that make CNC porting more efficient than doing it by hand, peripheral ports excluded.

[quote name='falcoms' date='May 16 2005, 05:32 PM']IDK, My dad is a machinist by trade and programs and builds precision (1/100 of a micron) grinders and has done mills accurite to 1/10,000 of an inch, so I don't get why it's termed so impossible to do it. You don't need any majorly fancy machines to do it, just a CNC kit bolted on to your basic vertical mill, zero it in, and away you go. You guys are talking like we are going to the extreme that we can't do it without multi-million dollar machinery. It's just not the case.


[/quote]

2D ultra smooth surface not a problem.

Have you ever seen an ultra smooth 3D surface from a CNC?

I haven't.

3D CNC still requires "stepped" machining which creates "terraces".

Apologies for the mangling of the nomenclature, since I've only dabbled with this stuff as a casual observer.





-Ted

[quote name='RETed' date='May 18 2005, 09:56 AM']2D ultra smooth surface not a problem.

Have you ever seen an ultra smooth 3D surface from a CNC?

I haven't.

3D CNC still requires "stepped" machining which creates "terraces".

Apologies for the mangling of the nomenclature, since I've only dabbled with this stuff as a casual observer.

-Ted


[/quote]





I alluded to that earlier, those stepped surfaces are why CNC ports still have to be hand finished.

"banzaitoyota...where is your R&D to prove that it won't work? I've backed most of my thoughts where you have simply slammed on the people pro-cnc....or not even pro-cnc, but ppl who simply give the idea credit that it could work under the right conditions."



No one said it wont work: IT IS NOT COST EFFECTIVE and it is not as good as Hand porting.



"and for your reference...i have well over 100 hours of CAD work (including custom designing for personal interests) and 5 hours or so CNC Mill/Lathe experience as well as a semester working with an automated assembly line"



Wow! 100 hours of CADD work, that is FREAKING IMPRESSIVE!. Come on down and apply for a job. Whats your specialty?. Yes I am being SARCASTIC, another big-eyed college kid who has been lightly exposed to the wonderful world of design.



Yes I have CADD experience, lots of it (more than 100 hours in a single month); seeing how I make more than the Engineers on the project I am on as THE 3D PDS Operator. Yes I have been trained as a machinist (US NAVY, Shipboard Machinist, It wasnt my primary job, that was a Nuke EWS).



Just because a program or a machine CAN do something doesnt mean that it is the right way to do something. For example: (A very expensive example) I was tired of inner coolant O-Rings that aren't quite the right size and not quite the right composition. So I called on some contacts in the sealing industry that I have worked with before and explained the problem. {side note: MAZDA R&D and talked with them in the early 70's also} We came up with a new seal design, I reached in my pocket and ponied up the R&D funds to produce a test batch. They produced a rather nice seal. Does it work? You bet. Is it cost effective? NO F'ING WAY!!! Design and technology can solve some problems, but the trick is : to solve the problem at a reasonable cost.



CNC Machining irons is not the answer to this dillema, as pointed out by the responders to this thread. CNC MACHINING does have its place in the rotary engine, ie Lightening rotors and production runs of parts. CNC is the wrong application of technology.

well im glad that you are soo willing to share your infinite wealth of knoledge with others. If you know something, then explain it reasonably in a WHY statement. don't just rock on other people putting in their best info, that isn't the best way to work in a group enviroment such as engineering/machining or a public forum.



"...IS NOT COST EFFECTIVE" again....please explain why. no amount of credentials is a substitute for relating the reasoning of a point. If you know, be a team player and give numbers and/or references to back up this otherwize unbacked claim. Im not saying your wrong either, if you know i want to hear you answer and be enlightned so this topic can be concluded. I'm looking for an intellegent answer from you so that all may learn from your experence exactly why this path should not be persued.



Speaking of the failure with the O-rings has nothing to do with this topic, but merely shows one ineffective solution (of many solutions) to a different problem. and where does your relative personal income have any relation to this?



JHB performance engineering wrote me a response to an email i sent them.



"We have set up our porting templates into a CNC Mill but we are still

"perfecting" this process."



if it were a total waste i think that they (professional engineers) would have given up on the idea instead of persuing it further. They are working on it and apparently have the basic idea and are refining it down to the final procedures. Hopefully we will be seeing CNC machined ports in rotaries in the near future.

[quote name='mazdaspeed7' date='May 18 2005, 09:02 AM']I alluded to that earlier, those stepped surfaces are why CNC ports still have to be hand finished.


[/quote]

Yeah, I saw that, but others don't seem to be listening to us. https://www.nopistons.com/forums/pub...IR#>/smile.png





-Ted

[quote name='RETed' date='May 19 2005, 05:00 AM']Yeah, I saw that, but others don't seem to be listening to us. https://www.nopistons.com/forums/pub...IR#>/smile.png

-Ted


[/quote]





Its only the ones with no porting experience not listening...

[quote name='mazdaspeed7' date='May 19 2005, 08:29 AM']Its only the ones with no porting experience not listening...


[/quote]



Yeah right... Those with no cnc experience are not listening... The hand finishing needed for cnc is not true, all of the cnc work I have had done for me came right off the machine with a near mirror finish, most of my parts came off of 6 axis machines, they leave it with a near mirror finish...While the grain of the metal will sometimes make it look it like there is a terrace, there really is none you cant even detect it with a feeler guage and straight edge, the only time there would be a terrace is if it was deliberate such as the cooling jacket mod on a rotor housing..

The best cylinder heads are not hand finished, they are cnc finished, the repeatability and balancing of the flows is so muc more precise with cnc, you cant even compare the to, even to the best and steadiest hand, all of the top head porters in the world, are now just feeding the know how into the cnc, rather than stabbing away with a die grinder..

And there is not alot of variance in rotor irons or housings, Ive been to shoos where they had one guy loading housings into a cnc machine all day long and pushing the start button , and the finished results are fantastic...

And what does that shop with the Multi Axis Machining center charge>?



What is their setup rate? What is there hourly rate?

In an earlier post I stated that a CNC machine *can* take out its own maching marks, but its quicker to just do it by hand.



I never said ports couldnt be CNC cut. I said its not a practical or economic solution to porting on a rotary.

If money were no object and the person programming the machine had enough patience to get everything loaded in exactly right, there is no way any human hand could repeat the consistency of a cnc. A machine could also do the finish work at the same time. Unfortunately just loading the program in would be a challenge in itself. You need a pretty creative way to get that machine's bit down the runners and at the right angles. Not saying that it is impossible, just not easy. How many housings will aperson go through trying to figure this out? I think with enough effort from a willing person that a cnc program can work out very nice. But they'll also have to load in many different porting configurations for many different styles of housing. That's alot of work to get that extra little tenth of a percent consistency maintained. It would also be alot of money. That's probably the single biggest issue. I know how cheap it is to go out in the garage and break out a die grinder. Can porting be done good with a cnc? Why not? Is it worth it? Each person will have to make their own judgement on that one. I wouldn't mind some cnc ported housings if I could get them for the same price that it costs me to port my own. For me it isn't a good deal. For a race team, maybe it is.

They were charging about the equivalent 250 a motor, and its done in less than an hour..

A friend of mine has been working on cnc for housings locally, hes almost ready to offer it up, it will be in the same price range.. There is no magic to accurate machining, the setup and the programming is not that difficult for someone that does it every day, my friend started as programmer for plastics injection molds that were quite complex, a port in a iron is a pretty simple task for someone with his back ground...That manifold adapter took him 2 hours from looking at the s6 and s5 gaskets to the finished product and cost 140.00.. It fit like a like glove...

I've seen tons of buggered irons from porting mistakes, search this forum for some prime examples... If I was blowing the money on new irons, they would only see a cnc machine for porting..Maxt

My money would still be spent on a skilled artisan doing the porting by hand. I just still dont think it would be the same. Show me a CNC port that looks like the one BDC posted in the "porting efficiency" thread without hand finishing.

My guess is that it has more to do with who owns the knowledge rather than whether one method is better than the other.



I suspect that most top porters come from years of building and developing engines.



Their experiance comes from engine building not machining. They have probably specialised over the year to doing ports as a major part of their business but building engines is basically what they do. They aren't machinists. If they do a great job with what they have why would they invest in CNC and learning it?



On the other hand if you know CNC you would need to learn how to make a great ports which I suspect would take time to learn and is therefore not cost efficient for a machinst to just go into the porting business.



Yes - CNC is high precision (probably higher than that needed) and CNC machine don't make slips but then top porters don't either.

[quote name='chalmers888' date='May 22 2005, 04:51 AM']Yes - CNC is high precision (probably higher than that needed) and CNC machine don't make slips but then top porters don't either.


[/quote]

Even the top porters make slips... Precisely why the alot of the top porters are using CNC...One can never be to accurate, remember the porting on our engines is also our "cam" timing, having everything phased properly is one of the keys to power...

Considering the fact that I have difficulty finding a shop willing to do small parts runs (90-100 units) due to the loss of set up time on their bigger contracts. I fail to see how you can afford to do 3 setups and 3 programs at a reasonable cost in order to port 1 engine. This does not even count the different styles of porting.





MAXT: I fail to see the cost effectiveness of what you are quoting. I want a name and a number of someone to talk to. Are you saying $250 for all 4 ports (ie 3 different setups, or is your price $250 PER Housing. BE SPECIFIC

Unless some high end CNC shop is doing stuff for charity, I don't see how it adds up.



Hell, I'll pay $500 for CNC ports!

I got cash on hand.

You guys wanna make good on your offer or you just spouting BS?



Sure, a high-end CNC can make mirror smooth finishes, but who the (*^#(*@$( wastes their time making rotary engine ports?



Sure, once the CNC coding is done, everything is repeatable - again, who the hell would waste their time with rotary engine ports?





-Ted

Im with ted. I have a bunch of engines under my belt now and I would never waste my ******* time going to a machine shop and try to explain to them what I want.



I just had an engine pinned and let me tell you it was not an easy thing to comunicate. I could not imagine dealing with the ports. It would actually be more setup time becuse you would need to change bits as well as use a zillion axis mill.



We got the charity rate of $175/hr. Clearly those of you who think it would be better to CNC ports have no clue.



Also, what would the benifits be over doing them by hand. I can think of none! It would cost thousands just to get tooled to do it. Baahhh, Im done here.



Those of you that thin cnc is the way to go, have you EVER ported an engine???

If you want to get your intake runners polished check out Extrude Hone; they do abrasive flow machining. I don't know if they will/can port the runners but they can polish the entire intake for under $600.



I might try it when i get a new engine.

Sometime I wonder why I even bother...



Who spends their time doing ports like that, hmm... People that are serious, thats who...

They guy I know, is working from from irons I gave him with with radius corrections plotted in, its not going to be mainstay work for his CNC machines, but shop filler in between large jobs, its better to have a machine making 250.oo then nothing...In between molds sometimes the cnc can sit for a week with nothing going in or out of it..

The problem with this kinda of stuff as someone mentioned you cant go to a machine shop and expect them to know you want or expect, and if its an hourly based shop,you are going to pay primetime money for every minute thats spent on it, be it machining , plotting or talking, but its not like that for places that have CNC machines that are in a niche market, but have down time to fill once the bread and butter is done, and thats the difference, anything they do over above their standard fare is gravy...

I am going there saturday for an update..Maxt