Can a machine shop port irons?
 

I forgot that i have some real nice 12a irons laying around and i want to bridge port them. If i have the templates, can a machine shop grind them for me? I found some sites that show where the grinding takes place, but i am still wondering what to go with. Some say the bridge port has to cut into the water jackets and some say no. Is it the half bridge that clears it and the full that dose not. These 12a irons are in great shape.:scratch: Oh, by the way i have a 13b 4 port with a fresh rebuild and street port.:icon_tup:

http://www.rebuildingrotaryengines.c...ting_templates

This will help, you CAN do it yourself!
its real easy just start on a bad housing then when you think you got it do your good housing!

sorry forgot to mention that all the actual "cutting" is done with a dremal!
You can buy all the bits needed from racing beat or your local industrial supply store.
I cant state enough how really easy it is but just remeber your first one may not be right so dont put new parts in it i suggest buying a used motor that runs and buy the gasket kit once you get the first motor done and your comfident in your work you can then do a "good" motor with new apex seals and all.

Your takeing the next step in engine building so tread lightly do your research and be prepared to fail.

if you dont feel like this is right just send your parts to a shop to be done and rest easy.

http://www.mazdatrix.com/videos.htm
another great resource

Machine shops aren't set up to port rotaries unless you find one that has someone with rotary porting experience. Porting is hand work using a die grinder and possibly a drill press for the pilot holes at the start of cutting the eyebrow for a bridgeport. A 1/2 bridge is when only the primary or secondary ports are bridged, usually the secondary ports. A full bridge is both primary and secondary ports, a J-bridge or monster port is the one that gets into the water jacket.

My first question is why a bridgeport, what do you plan on using the car for? Some say a 1/2-full bridgeport is streetable, I have to strongly disagree with that. I have a 1/2sp-1/2bp 12A in the widebody and it was a major pita to drive on the street until I installed the dual Weber DCD carbs. A full bridge I wouldn't even consider trying to drive on the street with any regularity. If you go with a 1/2 bridge or more, you should port the exhaust too.

NoPistons . com has excellent info on porting in the Engine Building and Porting section.

Just port it yourself.

My plans for the car is just to drive it around once in a while. Take it out on weekends. I only live 4 miles from work, so 50 miles a week or so. I want a fast,fun car to drive. I may take it to the track to see what it will run, thats about it.I see alot of videos of people with bridge ports and it dose not seem all that hard to drive. If i lived in the city, maybe.

maybe a nice big streetport?

yeah go streetport for dd.

I went over to Nopistons and they have great info on porting. I am still confused about bridge porting. Some people say that you have to cut into the housings, and some say you do not. I am able to use the tools needed to port, but they say you have to worry about the angles so you dont have seals hitting the port. Also they say the size of the port changes the timing. So how do you know what to do?

After more searching and a few phone calls, i should go with a Half-bridge. I really like that brap. With the hp gains that should work right?

Notching the housings is optional in some cases. The notch improves air flow by opening up a larger cross section. I notch my housings and it's very effective. What should you do, keep reading, learning, then buy a template from a reputable shop. There are different sizes of templates, the Racing Beat one for example is supposedly a small bp. If you want a good street port template, find the one Judge Ito sells.

I personally would like to find a set irons or the templates used by Rotary Engineering back when they were still in business. Their 'Turbo Alternative' and 'Super Off-Roadary' 13B engines produced 225 and 240 hp respectively. Their catalog doesn't say if their engines are street or bridge ported.

To do a REAL bridgeport, the RIGHT WAY, as GOD HIMSELF intended -
you do notch the housings.

Personally, my belief is that you should notch the housings on a naturally aspirated engine, and not on a turbo setup.

In what cases would you have to notch the housings? Does it deapend on the condition of the plates? Really to be honest, i want the brap. I cant get over how great that sounds. From a Street Port to a Bridge or half bridge port is there really that much of a H/P difference? 20-25 h/p is what it is.

Bevel the rotors while your at it too.

this will mean new fuel delivery and your going to need to beef up your drivetrain or you will be replacing things every time you drive it.
$$$$$$$$$$$$

You just want the brap, then just port the exhaust ports up a 1/2 inch and forget the rest of this crap.

I am still new to all of this Rotary tech so i dont understand the whole porting thing. I know its like putting a mild to hot cam in a v8.If i knew how to share links i would. There was one diagram i was looking at that should the timing degrees, i guess when porting.If it is that finicky than i can understand being hard to drive at low rpms. When i lived in NJ, there was a couple of 7s and one was ported. The only hard thing about driving that was the "bronze clutch" I dont want to waste your guys time with this but ithought you had to port the irons to get that lope and not the exhaust. The Wankle is a simple engine in one hand but hard to understand on the other.

Porting is similar to exchanging cams... except there's no going back if you take it too far.

Just like swapping cams, you're changing the opening/closing timing, and the "lift" of the "valves" that controls F/A mix entry and exit from the working chamber, for purposes of increasing flow.

the brap is due to more overlap from exhaust to intake. so correct me if im wrong but if you move the exhaust port up you will increase overlap with the intake and get the brap brap brap.... however it will probably have less low end, and if nothing is done to the intake ports it will have less power than a nice streetport...

Exactly. You win a cookie.

The condition of the plates does not determine if a notch is necessary. The condition of the plates determines if they are usable at all, and how much they need to be lapped straight/smooth in order to be used.

The wider the bridgeport is, the earlier your bridgeport opens, the more it necessitates notching the rotor housing. Most people here just bevel the rotor housing and do not cut deeply into it.

You're on the right track, keep learning. If it were me I'd send the block out to get ported professionally as I don't have the time to practice to get it right. Plus all of your drill, grinding, sanding bits, and practice motors are consumables and cost you $$$...........

can i have my cookie now im getting hungry

No cookie for you!

Question, when you say bevel the rotors you mean only one side our both sides of the rotor. Also wouldn't that make the corner seal seat a little weaker and does it affect the balance of the rotors drastically if at all?

Generally the housings are notched to match the eyebrow on the bp. Notching rotors is a whole 'nother game best left to the real pros that can also balance the rotors after notching. Rotor notching is getting into the extreme finer details of porting.

So there is more to it than just porting the irons?I have searched for hours and can not get a straight answer on what is really involved in doing this.The short videos i have watched just show using the templates.So safe to say its best to find someone that knows what they are doing. I just dont want to get raped in the process.

The way I started was by gathering as much info as I could and placing it in my HD. Bought a set of junk plates, die grinder and double cut carbide bits and went to town. After that I posted the finished product on nopistons and asked for advice. 3 years later Im porting my own engines. Be patient and always have your ears open there is alot of good advice floating around here.

$$$$$$$$
its all big money remeber that your going to drop AT LEAST 3,000 into this upwards to 5,000

the seal and spring alone is around 1,200 if i remeber right
add 1600 for new housings
and another 1,400 to have it ported by racing beat

then add however much you want for what kind of fuel delivery your going with carb my reach to 1,000+
Fuel injection is big money 2000 or more with aftermarket ECU wich is a must

VJ I am debating what to do with my SA's power plant at the moment as well. The power hungry side of me says there is no room for the 12A and it most be replaced with 13BT. The part of me that has to fund the project thinks maybe blow thru ported 12A is the way to go. More reading to come. Anyway i meet a guy off the forum about a front air dam a week or two ago and he had one bad ass drag car... bridge ported, NOS, ford 9" full cage very neat car. He had a banner on the front windshield..."Roman's Rotary Engine Performance 678-358-0242". It seams this guy has a local following for porting in the drag community around here. Like i say i have never talked to him but maybe worth a call. Let me know if you talk to him and how it goes.

Wow, thank you for the phone number.I am about 3 hours away from Atlanta. I will for sure give him a call Monday. Its is hard to find anyone close by me who works on Rotarys. Maybe he is friendly and will talk to me.Turbo would be real nice, i see alot of vids with 1st gen turbos and the look nasty.If i can acheive 225 or so hp out of a carb 13b i think that would be good enough for such a small car.That is about the same hp as an older stock 5.0 Mustang and they ran stock about high 13s low 14s. I dont want a race car but a lil pocket rocketI hear so much conflicting storys on the reliability of driving a Bridgeport and how long the motor last.I for sure do not have the money to keep pulling my motor apart every couple months.As i posted before i will drive my car maybe 10 miles a day and around town on the weekends. Gas money is not that much of a problem being i had a 96 Chevy with a 5.7 sitting on 35s. From what i have read a massive street port is good also, but when you bridge you start to get the lope" brap". That sounds so sweet.

Really?? They were more like high 14's or 15's

With all the jap turbo skylines etc running around a fast street car is now in the 13's.

Mine runs a 14.2 (be more like 13.4 at sea level) with 227 rwhp and there are so so many faster cars out there.

Aaaah found it!

Mustang Performance
1985 Ford Mustang GT
0-60 mph: 7.2 sec
Quarter Mile: 15.9 sec

Didn't take much to beat them back in the day....however those who hast them thought they were FAST

wow i was way off.LOL!! I just want a quick car.

Like Men in Black said.... you're going to be deep $$$$$ into this project before you ever here the *brap* the other thing you need to remember is that HP doesn't make your car fast. Torque is what makes your car accelerate quickly. What I'm getting at is, what good is making 225 hp if you have to rev to 10k RPM to see it? My recommendation... get over the *brap* and go turbo. I'm in the middle of a 12a blowthrough build and will be shooting for 250hp or so, at around 7-8k rpm. But more importantly i should have a nice solid torque curve of a little more then 200 lb/ft of torque through almost the whole rev range.

Also, if you've already got a sidedraft carb Robert@Rotary Shack will boost prep it for around $100. The way I figured, if I didn't tear my engine apart to streetport it, I could have turbo'd the car for a little more than $1000... compare that with bridgeporting and all the supporting mods to go with it and you're going to be at least triple that.

I paid 700.00 for my motor. I was told it was street ported. I have to buy a intake, header, carb, clutch and pressure plate. If i am lucky i can get all of that for about 600.00 if the guy still has the parts. If not i am going to spend a little more and get them piece by piece if im lucky.From what i was told and read with the set up that i will have would be good for about 210-225ish. That would be with a Racing Beat intake,Race Header and Holley 650. If i go with Bridgeporting i would have to spend money on gasket set, 130.00 or so and another couple hundred for someone to port it for me.From what i have read that would give 245 or so hp. I dont understand about the curve, but i know you dont start getting hp till 5 or 6 grand on the tach.I think that would be a good range to be fun on the street. Either way i have to spend money. LOL!

tell me you looked at the engine and it looks like it has been tore apart please tell me you got the recipe from the port job????

And if it is ported stock fuel system WILL NOT work it will need upgrading wich is more money.

I bought this motor off a forum member. I have been to his house while the motor was apart on the stand. I trust this man until i need not to. I had a 12a with Racing Beat intake and Holley 465 with a Holley Red fuel pump. I have the basics, just need the meat and potatoes. I had to sell the 12a stuff because it wouldnt fit. From what i was told you can use 12a irons with the early 13b. So if i can use them that is one less thing i need.

ok just checking to make sure.

Thanks for the concern, you really cant trust no one these days.:lol:

I dont think you'll be finding all those parts for $600.00 and if you do there going to need a rebuild or some tlc to get them back up to spec. Why not learn how to port yourself? It isn't hard. I saw a thread you made about keeping interest with you car. What better way to keep yourself interested than to lear how to port?! :) I hope I didnt sound like a dick, but everyday I log to see if any fun new topics are being covered and everyday I see the same topics from 2001. :( Either way goodluck. :icon_tup:


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