Well, I've finally started working on my carb and intake manifold because they are apparently the biggest problem with the Rex right now. I think the carb is causing the majority of my problems. Anyway, I've modified just about everything else under the hood so I figured I'd pull off the carb and intake manifold as well.

So far I'm in the process of switching to an E-fan, I've taken out rats nest, ACV, added a strut bar, put on a new water pump, took off air pump, put on the yoohoo belt, taken out hot start assist, done a couple of MMO baths, flushed the coolant, changed the fuel filter, rb header & presilencer, and new centerpipe w/ muffler.

Anyway, I'm hoping to have this baby hit the street by next summer. The way i can see it the only thing left standing in my way is carb, and brakes. I've got a bad wheel cylinder, and I think the carb could use a rebuild.

STERLING OR RX7CARL IF YOU'RE READING THIS I'M PRETTY SURE I'M GOING TO BE GETTINNG YOUR LEVEL 3 OR "STERLING CARB." HOW LONG CAN I EXPECT IT TO TAKE?

I've got all the intake off and basically I want to know what I should do to this thing while I have it off. Emissions are not a problem, and I'm obviously looking for horsepower here. My goal is to have about 150hp with the nikki carb.

First question. What is the little plate in the top left hole of the manifold? Are these the "ports" that everyone is always talking about? If so, this would make mine a four port right? The plate is apparently controlled by some other emissions devices that I have already removed. To me it looks like this thing is ruining the air flow. Can it be removed or modified somehow? (Sorry about the crappy pics, I think you guys know your way around the car good enough though...)



Secondly, where can I get all the gaskets for this stuff when I'm ready to put it back together? I don't have a local Mazda dealer anymore. Can I buy what I need online?

Third, the holes where the coolant flows through the manifold. I know many of you have mentioned blocking them off, and I think Rx7Carl has mentioned it as well. How does one go about doing this? Would doing this be beneficial to me, or should I stay with stock? If I do stay with stock, where can i find the little rubber gaskets/washers that seal the holes? The old ones were extremely nasty and can't be reused. I think this thing was using original coolant still... Also, how can I clean out the carbon that is built up in the manifold?



Here is a bonus shot that I thought I'd throw in. I plan on cleaning this up very well.



Final pic, I've been working on the air cleaner, so It will work a little better for the time being. Eventually I'm probably going to be getting one of the Racing beat ones though.



I appreciate any and all suggestions of what I should do to these intake components. I want to maximize the performance of this little 12A, using the stock carb. I enjoy seeing how much you can possibly wring out of the engine by improving little things on the car.

Also, RX7Carl or Sterling, if you guys happen to catch this thread, do you have any pictures of a finished Sterling carb? How hard is it to tune one of your carbs? Is it something you could conceivably talk me through if I have trouble with it?

Thanks in advance everyone!!!!

 

IANCOS*, but here goes

- you can safely remove the butterfly formerly controlled by the now-removed shutter valve.

- look at mazdatrix.com and victoriabritish.com for gaskets, o-rings, etc. Your local parts stores may have some of what you need. Mazdatrix sells blockoff plates too.

- I hear Amsoil PowerFoam will work well for the carbon buildup.

- I think I heard Carl talk about using freeze plugs to block coolant flow to the intake manifold. A cold air intake would help cool intake too.

HTH

*I Am Not Carl Or Sterling, just a disciple

 

I work at NAPA and have both things that you need. Go there and order the intake gasket that mounts the the engine and intake. They also have a carb kit that comes up with a blow up diagram. Kit is about $24 and gasket is $12. If you want a really good rebuild kit, get the one from mazdatrix.com. Also the gasket has those o rings you need too.

 

Glazedham, click on a link in my sig and email either Carl or myself. Everything you've asked about has been posted a buch of times. We'll be happy to dialogue one on one with you.

 

So how do I go about removing the butterfly on the shutter valve? I've read a couple of places that I'm supposed to take it completely out, while other say to just wire it open.

I saw somewhere that Rx7Carl mentioned the port is made bigger to compensate. So do I just take the shutter valve off the outside and then wire or zip-tie the butterfly open permanently? Also, when I take the shutter valve off the outside, is that going to leave me any unfilled holes that will make a vacuum leak? If so what can I plug these with? Thanks again guys!

 

Sensible questions...

The valve pot can be removed, and the valve wired in the open position, or the valve plate itself can be removed, but the shaft left in place, ensuring no leak.

In the past, I have had success removing the whole thing, shaft & all, and plugging the shaft hole with a piece of soft aluminum dowel.
I have a lathe at my disposal, though.

I do not trust JB Weld to fill such a large hole, though people have used it with great success as well.
I recommend using a bolt in which the head will not fit through the hole but the shaft of the bolt fits loosley through, along with JB Weld as a sealant/epoxy glue to keep the bolt in place.
You'll be able to reast assured that it can't vibrate into your intake.


These things are done most easily with the manifold out of the car.
I suggest you simply wire the valve open until you are ready to remove the manifold for gasket or carb replacement.
...Nothing's more frustrating when doing manny work than dropping something down into it while it's still attached to the engine!

 

you could always replace the intake with a 79

fixed my prob

 

This car's not my daily driver, so everything is already off! :-) I thought I'd get it all out of there yesterday while we had some reasonably warm weather. I didn't want to be out there banging my knuckles in the below zero weather trying to get the carb and manifold off. :-D

Sterling, I had read a few other posts and Carl mentioned that you will want to leave the butterfly in place but just wire it open. He said that if you completely remove it, the manifold will suffer because it was designed to have the butterfly in there. Should I take his advice or just go ahead and rip her outta there? What would happen in worst case scenario if this was taken out? Rough idle? Thanks again for all the help.

Jamie

 

Late chime in. Id leave the butterfly in, just wire it open. You can see how big the runner is in that section, thats to compensate for the butterfly. The control valve can be removed and the opening blocked with epoxy.For street use, especially in Indiana, you should probably keep the coolant passages in the manifold if you plan on winter driving. If you do decide to block it, you can use 20mm freeze plugs in the rotor housings.

Good work on the airbox. But remove that little heatstove pipe. Looks like you already have a K&N element. Maybe you should consider my airbox mod instead of a RB unit, its cheaper.

 

THanks carl. Yes, i do have the K&N but I'm not sure ive seen your airbox mod? Do you have any pics of it? I'm always willing to look at alternative options.

When you say epoxy, would Jb Weld fit the bill? I'm not sure how big the hole for the control valve is after you remove it as i obviously haven't removed it yet. I'm guessing it's fairly small?? Do you have to put anything behind the hole to get the epoxy to stay in it?

Also, do you have any pics of how to wire the butterfly open? What do you wire it to if you take off the control valve?

THanks again.

 

Look for the "Arr box improvement mod" thread (yes I mispelled air, sue me).

Yes AFAIK, JB weld is fine for that. I used the epoxy that comes in a stick, that you slice with a razor/knife then knead like a clay. It can be stuffed into the hole and doesnt ooze like liquid epoxy. It's sold under various brand names.

You could put one of the bolts back in, that would give you something to wire it to as I recall. Been a while since I done this sorry.