I repeat, there is NO BENIFIT in porting intowards the inner part of the center plate.

It is only detremental to the life of the components I mentioned, it should be cleaned up, but no material removed, for the reasons I stated.

Where the factory inner edge is on the std plate is the limit, this is in within .08mm to the inner sharp edge of the outer oil seal and basically should never be touched.

When you have an engine apart, partly assemble it and spin the rotor around and see how much of a gain you get from butchering the inner edge of the port, it is nothing! ALL it does is degrade your sealing of the outer oil control ring and allow the problems I stated before, there is only a very small time in the cycle that the "extra area" is exposed, the rest of the time it does nothing, and in the scheme of things it has no advantages at all.

For better flowing performance ports you need earlier openings and later closing time, this practice of moving the edge in towards the outer oil control ring area does neither !

These are the facts, extra area gain in the oil ring side is exposed to unhindered flow (by rotor side) for about 90 to 100 crank shaft degrees where as outer edge "opening" and closing edge "roof" are exposed to around 270 degrees of unhindered flow, also it is happening at a much more critical time in the cycle when the flow is being initiated and stoped, the simple engineering facts are that opening up the port in towards to oil control ring are will result in minimal gains-end of story.

 

are you saying only on the center plate (primary) and it is ok on the outer plates (secondary)
i went down and out on center plate and up down and in with bridge on outer plates.

 

I meant to say end plates, not "just" the center plate.

sorry.

 

That circle or "ring" is where Mazda do special heat treating to stop excessive wear and help the oil control rings over the life of the engine, when you tear down a worn engine there is a circle "perfect" where the outer oil control ring travels in an eliptical motion, this just happens to match up VERY close to where the standard inner edge of the secondary and primary ports are located.

Now there is no problem in moving the lower edge further down or upper edge higher, but moving the edge in towards the centre of the housing will only result in exposing the outer oil control ring running edge.

Your edges "seem" to go a fair way into this area, which would result in the outer oil control ring (sharp sealing edge) being exposed in the intake ports...something that is not meant to happen in my opinion. Oil contol rings have a hard enough job to do at the best of times, this modification to the intake ports would only reduce the effectivness of the sealing grid with a VERY small gain in port performance (if any).

Those Primary ports in your engine could come down another 10mm or 1/2" plus the back edge near the outer water o'ring could be further back, this plus other detail mods to the closing timing would yield far more flow potential due to a little more overlap and slightly later closing time.

Just my opinions, maybe I should keep them to myself

 

i like that you voice your "opinions" it will help other people when they look at there porting or if they attempt to do it them selves

 

i don't mind opinions but from the original posts it seemed those housings were now garbage but they are just opinions that they seem to be bad. i could have no problems with my engine.... when i stop by the shop friday if the engine isn't built already i will get pix with the rotor on top to see if this actually the case. thanks in advance for getting me worried half to death!!!

 

Amen. Not just porting either, every other post that RICE makes I read so I can learn more.

 

Vosko, did not mean to worry you.

I suppose it is just something I do not agree with and cannot see the benifit in doing it the way that your builder has done it.

I suppose if the outer oil control ring does end up being "exposed" so long as the inner one is doing it's job then all should be ok, How long for, is another question?

Yes and it is just an "opinion" (on oil ring performance) with the porting flow it's a bit more scientific (I have too much time on my hands!). There was another guy on this forum who had oil consumption problems, however his engine "porter" contacted me and assured me it was nothing to do with the fact that the outer oil control ring was exposed, it is something that needs to be investigated more though I feel, in terms of what long term affect it has on the outer oil control ring.

Mazda state very much, that too rich an idle/low load mixture has a drastic affect, in that it shortens oil ring life and that is with a std engine (with out the rings exposed, ie inner one protected by outer) I suppose a long term test would be the only way to find out the impications of such a modification.

 

You gotta look inside the intake ports and spin the rotor around and see if you can see the inner shinny edge (seal contact point) of the outer oil control ring. If you cannot then all is good, if you can see it, then this is not the ideal situation.

 

my engine is fully warrantied by the builder. generally speaking his engines last and take lots of abuse. i haven't seen one fail yet from builder flaws. i'm gonna try and have him post on here but his computer was down. i'm gonna call him tomorrow and ask him about it. i asked a few other people and they all said its fine. oh well guess we will find out soon

 

i will *try* and take pix i dunno if its possible though. for you guys to check out

 

Well, I just cut through a rear "old" housing (to see the intake port on it's face and see what seals run where) I had and here is what I saw.

Where the inner edge of the primary and secondary port run (near the cirlcle Vosko mentioned) there is no real room to open this edge up (less than 1mm as I mentioned earlier). If this edge is brought in closer to the middle of the housing the sealing edge of the oil control ring will "empty" into the intake port. It was not designed to do this, this will result in increased oil usage of the engine and will expose the outer and inner oil control ring to raw unbured air fuel mixture, which is not a good thing.

Think about how they work, the outer ring needs lubricant to seal and last for it's design life, it is basically getting this diluted and lost every time it goes past the intake port! if you lower this edge closer to the center of the side plate.

The amount of oil that gets traped between the inner and outer oil control ring plays a vital role in the life of these seals and allso in how much oil the engine will use in service, I find it very hard to believe that porting to expose the outer oil control ring would not have an effect on the above items mentioned.

My tip, make sure you do not cut into this area. I cannot see any reason why you would want to do this ?

 

aren't the different year housings different ? i have FD housings. it is also possible a photo could be deceiving. but from looking at the unported housing and ported housing pix there is only a slight porting of the side...... there is only one way to tell for sure, i will take pix and post them ASAP

 

Yeah the housings are different though Mazda has not changed the geometry of the oil control rings since the 10A !

You will find all the modern rotaries (Mazda ones) in all there side ports have the same edge relationship (for the outer oil control ring) from the center of the side housings. How low/high/& far back (towards the rotor housing) the port goes varies between some generations.

The plate I cut through was a 87 13B Turbo rear housing, chopped her up just near the thru bolts right into the intake runner !

 

And yes, photo's can be vary deceiving !

Ever met someone of the Internet ?

 

well. my car can't possible smoke as much as it did before.......

 

I think if it was ported in far enough to expose the inner oil control ring it would not smoke as much as that !

That looks like a sceen from a "Cheech and Chong" movie

 

that is bad coolant seals and NO OIL SEALS!!!!! yeah engine was toast..... anything will be better than what i had

 

You should have seen my car when I first started it with my 1600 cc secondaries accidentally running at 100% of the duty cycle of my primaries! I'm now the best neighbor in town.

 

Neighbour's reaction

My reaction

 

It was pretty cool. It looked like my yard was on fire.

 

i just talked to Ito. he is gonna try and post on here tonight. he said there is nothing wrong with the porting

 

Bout Fukeing time!

 

Vosko,
I had some porting done to my engine in which the inner edge of the ports was "sightly" moved inwards and my car smoked real bad. I'm not saying that the same will happen to you, but you're porting is alot more aggressive than what mine was. If you want to see some pics of the porting, they're here http://photos.yahoo.com/bc/tu6dolce/...riends&.view=t

Rice Racing,
Were you referring to me when you said the "porter" called you up? I sure hope that ******* didn't do something like that.

 

yeah i saw the pics already. its very hard to tell from pictures. ito told me spec'd out everything and it will be fine. not eyeballing like everyone else