My ports, My ports
 

So what do you think about my ports?

More pictures.

The last pic in the first row almost looks like you cut into a water jacket

and you should take a polishing tip. and go over them i can still see every mark where your tool traveled..

Looking good!

From the pictures of the primary port it looks like you could put a bit more gradual radius on the short radius side (opening side opposite the oil seal side) and make sure to cut back the top of this short radius some where the port has been extended upward.

Can't see that radius in the 2ndary ports at that angle.

And I could seed doing a tiny bit of tidying up all around- but I fidget things to death.

The last pic in the first row almost looks like you cut into a water jacket

Nah, that is rough cast area left over from stock ports. It is best to do as he did and NOT cut down all the material around that deep spot to get rid of it as that area will gain too much volume and too much bowl shape.

and you should take a polishing tip. and go over them i can still see every mark where your tool traveled..

That may actually have an advantage on the short radius sections to keep airflow attached and all over on the primaries to keep the boundry layer thicker so fuel doesn't condense on the port walls. For the 2ndaries I could see flapping the bowl area smooth (long radius leading up to sideseal track) to thin out the boundry layer so the port flows like a larger one.

There are lots of ways to port and most of them have their own advantages/drawbacks.

This porting looks good to me for running on a stock ECU or stock ECU with piggyback you wouldn't have to tune around driveability issues.

I did not do them, and I don't want to say who did them just yet.

Are you sure? I'd like to see another pic of the port in question, from the anle of that pic it really looks like small intrusions ino the water jacket

I could be wrong (like thats ever happened - haha) but maybe another pic or two of the same port would clear it up.

Are you sure? I'd like to see another pic of the port in question, from the anle of that pic it really looks like small intrusions ino the water jacket

Hmm, I guess it could be an intrusion. As you say, can't tell everything from pics.

Just so we're all on the same page Im talking about these.....(need to click the thumbnail to see what I circled)

that isn't the water jacket, the rotor sealing surface is a flat piece of iron that is cast to the rest of the iron, if you look at a stock port iron you can see what i mean as the flat piece of treated iron is about 8mm thick and where it meets the rest of the iron there is some variations where the sheet meets the casting.

the porting needs work as that pic it looks to have gone into the oil seal track not the water jacket. did this engine smoke? i tend not to touch that upper inner port wall since even stock it is very close to the oil seal track, there is not much room to work with there so i just smooth it out as much as possible for the air flow path.

lastly, yes the porting should be gone over with a flapper or wire wheel to smooth out the grinding, the porting is very rough and airflow will be hindered by the roughness, though primaries there should be a little turbulence that is a little too drastic.

the ports are rather wide as well, corner seal sticking and or rotor corner seal groove wear could result as the corner seals will only have a few mm to travel on as they pass over the port, this will load the corner seal at an angle.

Just so we're all on the same page Im talking about these

Ah, those.

Those marks are left when Mazda uses a mill to cut the proper port ouline into the iron on a side housing where the casting cores have shifted away from the center of the housing.

This particular core shift trait is highly desirable (only if present on both sides of the int. housing) as it allows more port blending of the long radius up to the oil seal track.

I think that may be why it looks like this housing is ported too far into the oil seal track; though I did not try to discern whether the basics of safe porting were present such as not porting into oil seal track, not porting too far into cornerseal track without proper adjustments (a real judgement call there.)

The opposite core shift (toward the center of housing) is terrible as it leaves a lip at the oil seal track that cannot be corrected and the housing will flow less.

These ports look similar to some Pineapple ports I had once.

slightly different interpretation but it is basically the same explanation, most of the time there is a lip where the port flows into the iron as the casting is usually below the surface and i have never seen a cut housing that you could cut much into the actual face of the port where the oil seal runs since that port is relatively uniform through all irons though the castings are always different.

this is a good example as you can clearly see the port running beyond the oil seal track:

https://www.rx7club.com/attachment.p...hmentid=182378

Looks like a good first effort, but I'd like to reiterate that the oil seal track must NEVER be violated.

You can do a lot more back cutting under the corner seal track inside the port, as well as the corner where the opening edge meets the closing edge of the port.

Keep the runners small and smooth unless you have an aftermarket intake manifold, or big port job on the stock one.

Have fun while it lasts. :)

I've been able in the past to cut into the oil track slightly without any noticeable oil consumption. However not as far as those ports. Defineatly a different porting style than what I'm used to doing in the shop. Let us know how it works out for you, and who did them.

i will tell you a little hint about porting. it isn't so much about the shape of the bowl or how big it is it is about the path of airflow, back cut under the port as it enters the iron and you will get much more airflow than spending a ton of time blending the bowl and polishing the hell out of the ports. ;)

"the porting needs work as that pic it looks to have gone into the oil seal track not the water jacket. did this engine smoke? i tend not to touch that upper inner port wall since even stock it is very close to the oil seal track, there is not much room to work with there so i just smooth it out as much as possible for the air flow path."

"the ports are rather wide as well, corner seal sticking and or rotor corner seal groove wear could result as the corner seals will only have a few mm to travel on as they pass over the port, this will load the corner seal at an angle."

This engine had about 6 thousand miles on it. I took it apart because of coolant seal problems. I noticed the corner seals when I took it apart but was not totaly sure. The enging was built with 3mm apex seals and solid corner seals. Like I said before I did not port any of it. These are just a few pictures I took after I disassembled it.

This was not this guys first time porting. He is a fairly reputable engine builder and rather well known here.

OK..............so are you going to make us play the guessing game on who for another two pages of critiquing on the ports?

No, Im not going to tell because I dont want to get into it with him. I am not trying to start shit with him! I would like a few more pointers that I could do to fix them from a few more people.

well no offence to you or whoever did these ports but if you're going to do any work on anything and you get all up in arms because of some crituqing/pointers/advice from other experts then you may as well pack your bags and head out the door....

Im a body man and if another experienced bodyman gives me advice or tips on something I may be doing incorrectly or something that could be done better - Im always open to it and wouldn't consider it to be "starting shit". I prefer to do things the best way possible......and sometimes thats not my way......Its all a learning process and once you stop learning, you stop the process.


Anyways, I have obviously been corrected on my observation and it seems apparent that there are other more vital issues with the ports that Karack covered so I guess my knowledge has reached its end for this thread.

your port job brings all the boys to the yard....
and their like....it's better than yours
damn right it's better than yours
I could teach you but I'd have to charge.

haha I dont know why that popped into my head.

Very interesting read, I will soon be porting my engine too for the bnr stage 4 turbo. There are lots of theories on porting but I will just be using templates. If it doesnt make the power I want I will just up the boost.

You took it wrong I am looking for pointers. I want to talk to the person who did the work first, like I said the engine was burning coolant. This is my second engine from this person, LONG story that I dont want to get into. I will post more pics of the one port later.

.......

my final comment is:

i hope the port job at least wasn't very pricey. i could do a similar port job, even better in about 45 mins on all 3 irons.(not that i would choose to though, i like to take my time and do things meticulously)

I wouldn't worry about it. It's just a rotary, not like it is some high dollar piston engine that is going to throw a rod if you didn't build it right. The worst that can happen is the ports will eat a side seal, and it looks like all the lines look right to prevent that from happening.