I may be buying my friend's motor, which is going to be rebuilt. The rear housing will be replaced with a new piece and the front has less than 5000 miles on it. Dave at KD looked at the port work and said it's very good, but there is a small amount of oil seal path overlap. I wasn't sure what he was talking about at the time. He said it's nothing to worry about so I took his word for it. I've been doing some reading and now I'm not so sure I believe that.

What are the pros and cons to enlarging the port in this way? I use the car as a daily driver. I think I would benefit from longer motor life more than a slight power increase. Am I jepordizing reliability by going this route?

Dave mentioned that it will smoke a little if it sits idling for awhile, but won't when the car is moving. Does anybody have any personal experience with regard to this?

 

btw-The intake street ports were done by Hayes. I'd love to talk to someone with the same setup.

 

doodoo

 

I've got a spare set of side plates sitting here that had been ported the same way as you described(little bit passed the oil seal track) but few people told me they're not useable??
I will see if I could get a hold of a camara and take some photos of the ports.

 

This is from Gmonsen

"It should not be a problem and it will sound great... Ed Kim's was like that."

Sinful7, I've love to see a pic of your ports. I will try to get one of the motor in question some time this month.

Like many other things this may be a matter of degrees.

 

?? I upload a photo with a reply post, but I can't see my reply message?
I might try to upload to imagestation and then attach a link or something, just a minute.......

 

OK, another attempt. Hope it wokrs this time.
Primary port

 

Doh' I see red x, guess it didn't work this time either
How can I attach pics on here??

 

Right, after few tries in test area 51
Here is a Secondary port from a motor had water seal failed and 1 cracked apex seal.

 

You just messing around w/ that housing? Or are you planning to use it w/ the burns and all?

 

Another shot of seconday port

 

Very nice port-work... I'm just not so sure about those burns. If it were me, I'd actually pay the money to have the housings lapped, or hit them 600-800grit wet/dry.

 

I've been told that they are no good?? I bought another useable set which has smaller porting done than the above set. At this moment it will be used as a dummy block to make an exhaust manifold for a single turbo.

Here is shot of the primary

 

The porting was a friend's handy work, I would like to hear some opinions on if they are usable.

a shot of port runners

 

I think the inlet runners are too big for a street port, it's going to slower your intake velocity.

 

What does all this have to do with porting into the oil seal track? =)

I spoke to Gordon Monsen about this last night. He said Ed Kim has a motor like this and it has held up fine. Does anybody know his email? I've tried searching but I can't search for "ed kim" because "ed" is 2 letters. I get nothing by searching for "edward kim" and way too much when searching for "kim."

 

Not very symetrical but they could do the job. I wouldn't feel comfortable handing out porting if it looked like that.

 

Yea they looked quite bad might need some tidy up.
In one of the secondary port pic you can see clearly it's ported passed the oil seal track, are they ok to use for rebuild??
I know it's gonna smoke alot.

 

I've done some more research on this subject. My conclusion is that porting into the outer oil seal track will accelerate wear on the oil seal AND the port may catch and break a compression seal. The performance gain from this style port when compared to a normal street port is minimal because the extra area of the port is covered by the rotor for a large portion of each revolution.

Below is a list of the people I spoke to about this and what they said. Enjoy!

Racing Beat (Chris Engine tech): "Uh Oh" (after I told him the housing I was planning on using had this characteristic) He went on to say it will shorten the life of the oil seals and can break the side(or maybe it was corner) seals.

Mazdatrix: (Jeff) It can catch and break the side seals. It should not be done under any circumstances. "It is not a grey area, if the housings have been ported in this far THROW THEM AWAY."

Mazdacomp (Tim): "Bad idea....It will increase wear on the oil seals and can catch and break the side seals."

Rice Racing (thread listed below): “For the very marginal gain in port opening area (less than 5%) That porting is VERY bad practice! It will result in excessive outer oil control ring wear due to excessive exposure to raw air fuel mixture. It will not provide any gain in flow due to port timing improvement as for a large majority of the time the extra area ported is covered by the rotor side...”

Judge Ito (thread listed below): The very first lesson a Rotary Engine builder learns about porting is: never port into the center of the side housings(no gain in power or anything else and exposure to the oil seal ring is no good.

https://www.rx7club.com/forum/showth...l&pagenumber=3

 

Hi, i have motor bridge port with this trouble.
All morning i start is burn oil ( a lot of smoke 3 minute about ) same trouble if i stop the motor for 2 hour or more ( but less smoke one minute ).
One morning i remove the lower intake and i notice oil in this section oil from rotor seal.
Never put this hausing plate in your motor.
Thanks

 

ed kim sold his junk engine that was ported into the oil seal. he now has a pineapple racing engine. FYI

 

Hey CCarlisi thanks for th info
I was hoping it would be ok to use them, luckily I didn't use this set.
Thanks again everyone