wankelhead

well,i was wondering if anybody had some pics of the port area,looking at it with the lower intake manifold removed,and inspecting the ports looki'n throug the intake ports....thing is,i got a new motor here recently from someone[a somewhat well known shop],i paid them to do a street port on the rebuild,and i'm not really sure i got one...not jumping to any conclusion or anything,of course.first off-is it even possible to see a streetport from "outside"?i would think so,as i can see the rotor face quite well.unfortunately,i never got a chanche to look at my old core for comparison.the "edge" of all the ports are defined by a machined area,that is probably about 3/16-1/4"wide,a circle,if you will,around the ports,at,ohh,somwhere close to a 90 degree angle in relation to the rotor[sideface].from the edge of this machined area,it progresses into the intake runners,wich are,of course,rougher cast aluminium.i dont know if that is making any sense.i guess the thing is,that "machined area",is very consistent,and looks very much oem,and i doubt that the intake would just taper right to a point at the place where the sideseal would cover it[its a bit hard to explain].yet,that machined area,is where i would have expected to see some evidence of enlarging/smothing/etc.so,i'm hoping for some input,maybe some pics of ported vs oem side and center housings.like i sayd,not getting worked up about anything yet,but i wanna check this out!thanks very much,guys!
david

HWO

take the lower intake manifold off and poke ya fingers up the runners on the primary ports, the tops of the ports should feel like this \ / but not soo much angle, if it hasn't been ported, they will feel like this _ _

hope that makes sense

wankelhead

hmmm....not completely...when you are refering to the different angle,are you saying,that,lets say the rotor is in the position where it completely covers the port,and[for the purpose of comunicating the picture] you where somehow able to stick a angle gauge on the [side]face of the rotor,then the angle of the intake port "sidewalls" would be like,say,60-70 degrees on a ported motor,and like 90 degrees on a non-ported motor?is this correct?



ported? vs. non-ported?

_____________\............ /________ ______|..............|______
sidehousing
port oppening>.........

Blake

Let me guess...Hayes or Atkins? Regardless, porting is evident by the originally rough casting being smoothed to a nearly mirror finish. In stock form, the rough casting is evident all the way to the port aperture. I suppose someone could "port" an engine as you describe (assuming I understand what you're saying), but it doesn't sound like a good job. Porting starts at redefining the opening and closing timing (the port aperture shape), but to be effective, it needs to address the transition between the runner and port. Here are before and after shots of a primary port (center housing):




While this is a rather large streetport, it's similar to what you should expect. Hell, this was my first try. A pro should do even better. Unfortunately, most do not. I've seen porting from most of the major builders and 90% are crap.

wankelhead

blake-thanks very much for the reply.no,it was actually neither of those 2 shops.i got the motor from rx7 specialities.to get some clarification on the pic of the housing before the portjob[the red paint makes it a bit hard to see],do i see/understand corectly,that on a stock housing,the rough casting goes all the way to the inside edge of the housing?if this is the case,they did indeed do some very minimal "polishing",as that ring of "polished " area is sort of like if someone had taken a grinder to the port in pretty much the area where,in your pic,the red paint extends into the inside of the port[meaning,about that far],and polished that edge.is this correct?i will call them up and talk to'em,it would just be really good to know if they did anything at all,or not.hmm.i dunno about this.everything else looks good so far.

nice looki'n port job,by the way

wankelhead

^

Blake

Thanks. The roughness is from the casting process and it should go pretty much right up to the port edge, though there might be a lip. Regardless, anything appearing "machined" or feeling really smooth is a sign of porting, but as I said, a good port job would address the entire bowl of the port. Keep in mind, however, that you can't port 'in' toward the oil rings. Porting goes 'up' to extend the duration and 'out' (toward the rotor housing) to advance the port opening. Try running your finger along the top of the port bowl and feel if it's really smooth, indicating it was ported.