Anybody Port Their Own Engine?
12-12-01, 08:01 AM
#1
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Anybody Port Their Own Engine?
Hey Everybody,
I'm thinking of getting a 1990 Turbo II for a project car for autocross racing and to learn how to drift at the track. I basically want to keep the whole thing as cheap as possible. I'm taking a semester off from college, so I have several months of wrench time at my disposal.
If I were to read the appropriate books and learn to take apart the rotary in the aforementioned Turbo II, would I be able to port it myself? It doesn't seem to be more than just removing some of the metal with a grinder or something.
If this is just a ridiculous and terrible idea, please try to keep the ridicule to a minimum, I'm new to the working on cars thing
.
I'm thinking of getting a 1990 Turbo II for a project car for autocross racing and to learn how to drift at the track. I basically want to keep the whole thing as cheap as possible. I'm taking a semester off from college, so I have several months of wrench time at my disposal.
If I were to read the appropriate books and learn to take apart the rotary in the aforementioned Turbo II, would I be able to port it myself? It doesn't seem to be more than just removing some of the metal with a grinder or something.
If this is just a ridiculous and terrible idea, please try to keep the ridicule to a minimum, I'm new to the working on cars thing
.
12-19-01, 11:04 PM
#2
Are you Nucking Futs?
Join Date: May 2001
Location: Abilene, TEXAS
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FWIW there seems to be two schools of thought on this.
One says for optimum performance send the housings out to a well reputed technition for porting as you will never ever do as good a job as they will.
The other is more like "shoot, I got htis thing apart and I got an air grinder/dremel so why the hell do I not port this puppy!"
These are of course extremes and most rotorites seem to fall in the middle.
IMNSHO porting is best left to the experts if you can afford it. It will be done right and your housings will be safe and not butchered.
BUT...
I am broke and I have 6 12a's sitting around so while I have the sucker apart I am going to port it! (besides wich I desperletely feel the need to give integras and Civic Si's an old fashioned rotary spanking)
Hope my babbling helps
One says for optimum performance send the housings out to a well reputed technition for porting as you will never ever do as good a job as they will.
The other is more like "shoot, I got htis thing apart and I got an air grinder/dremel so why the hell do I not port this puppy!"
These are of course extremes and most rotorites seem to fall in the middle.
IMNSHO porting is best left to the experts if you can afford it. It will be done right and your housings will be safe and not butchered.
BUT...
I am broke and I have 6 12a's sitting around so while I have the sucker apart I am going to port it! (besides wich I desperletely feel the need to give integras and Civic Si's an old fashioned rotary spanking)
Hope my babbling helps
12-20-01, 12:11 PM
#3
Old [Sch|F]ool
Yes, I ported my own engine. Lots of people do it. (Although most of 'em also do it for money )
Basically the engine sat disassembled in my basement for about a year while I thought about it and looked at it and planned. It's not as easy as "just open 'er up!" because you have to understand what you're doing. There are three sides of an intake port and four on an exhaust port and they're all important and they all have different effects. Like on the intake port, the side on top will change your port closing time, the vertical side will change your port opening time, the hypotenuse doesn't do much of anything but you can't move it, the same with port opening - you can't move it much because a seal needs that area. Exhaust ports are simpler but IMO they're more important... get into issues like earlier blowdown vs. longer power stroke, port area, overlap...
So that's why I went with a real mild port. Concentrating more on making the intake port a smoother transition when it changes direction when it enters the chamber (Port runners not touched except to remove gross amounts of casting flash, and only port closing timing was changed, by only 10deg or so) and the exhaust port was enlarged to eliminate the "wall". Most peoples' street ports are much larger than my ports... a stock FD probably has larger ports than my ports. There was too much I didn't know at the time because you can easily change timing in a way you don't want, and unlike a boinger, when yoy change port timing you can't just put the stock camshaft back in, you are stuck with it. (OTOH you don't have to buy camshafts so it's a fair tradeoff )
)Basically the engine sat disassembled in my basement for about a year while I thought about it and looked at it and planned. It's not as easy as "just open 'er up!" because you have to understand what you're doing. There are three sides of an intake port and four on an exhaust port and they're all important and they all have different effects. Like on the intake port, the side on top will change your port closing time, the vertical side will change your port opening time, the hypotenuse doesn't do much of anything but you can't move it, the same with port opening - you can't move it much because a seal needs that area. Exhaust ports are simpler but IMO they're more important... get into issues like earlier blowdown vs. longer power stroke, port area, overlap...
So that's why I went with a real mild port.
Concentrating more on making the intake port a smoother transition when it changes direction when it enters the chamber (Port runners not touched except to remove gross amounts of casting flash, and only port closing timing was changed, by only 10deg or so) and the exhaust port was enlarged to eliminate the "wall". Most peoples' street ports are much larger than my ports... a stock FD probably has larger ports than my ports. There was too much I didn't know at the time because you can easily change timing in a way you don't want, and unlike a boinger, when yoy change port timing you can't just put the stock camshaft back in, you are stuck with it. (OTOH you don't have to buy camshafts so it's a fair tradeoff )