Ok, after 2 days of removing rusted and stuck bolts, finally I have my racing beat exhaust on!! wohoo it looks great, I can't drive it yet tho cause I have a few problems, first off i'm waiting for my new intake manifold gasket to arrive because the old one was brittle and broke into about 3 pieces. I put papertowel in the middle holes in the gasket I believe that those are the intake holes, the other 2 looked like coolent lines, correct me if im wrong so i can make some changes Also, on top of the carb, there are 2 fuel lines, one im guessing is in the other is a return line right? well there are also 2 bolts up there, I removed them and around each bolt there is a small screen looking like thing that got all torn up, umm what is it and do i need a new one now? also, the exhause came with 2 block off plates, could someone show me a diagram of where they go because racing beats sheet didn't help me, I found 2 places where it seems that they go but it doesnt seem right... I still have 3 extra screws from racing beat. So. to make it easier for you to help me:

1. intake holes

2. screens around bolts on fuel lines

3. the 3 screws and 2 blockoff plates from racing beat

(edit)oh sorry this is a 1980 12a

 

Yeah, the two holes that look like coolant, are coolant passages. People like to plug the passages in the engine to keep hot coolant from getting in the manifold as well as to prevent a potential leak... living where it gets cold, I elected to leave them alone. Just be sure you get the O-rings on right (get new ones, might not come with gasket) no matter if you plug 'em or leave them alone. Some people even just stuff a quarter (or whatever fits) in there as a non-permanent block off.

The screens like to go bad, it's a good idea to have them as they are the last line of defense in preveting crud from clogging the needle and seat assemblies inside the carb. In an emergency I eliminated them (completely full of rust) but better safe than sorry. That carb BTW was so crudded up that it's basically garbage. Makes a nice paperweight though!

I dunno about the screws, but the blockoff plate goes on the ACV. It's the chunky looking thing on the side of the intake manifold. Here's what a manifold looks like without the ACV (or carb, or rat's nest, for that matter)

 

I circled where I think the 2 plates go, am I correct? Oh and where do I get those screens at?

[img]manifold_0043.jpg[/img]

 

Well, I should have first warned you that that is NOT an '80 manifold, it's a later style that's been, ah, altered (part of how I get away with running with no ACV blockoff)

OK the small 2-bolt blockoff plate goes on the heat exchanger, which is the catalytic converter looking thing underneath the car. (It preheats the air coming from the air pump before it gets injected into the thermal reactor) The RB header will physically bolt on to the heat exchanger - so will a Pacesetter header, which is what I've got on there. If you also bought the mini-presilencer, the presilencer replaces the heat exchanger and you don't have to worry about the blockoff plate.

Oh I forgot about the screens... a rebuild kit might come with them, I'm not certain. My NAPA kit didn't. Mazdatrix does sell them, look in the intake section of their website.

 

umm I took off theonly thing that looked like a cat and I thought it was a cat? either way, the thermal is gone all the way to the presilencer, then the midpipe , and at the very end is the muffler so what is the thing on the left i have circled? but the thing thats circled on the center is correct, correct? (oh, btw my intake manifold looks exactly like yours for some reason..)

 

You gonna like this a lot better dude, no more back firing, no more tinny sounding exhaust!

 

I sure hope so! And if I can do it (a 110lb 18 year old computer nerd) anyone can do it

 

I dunno what the thing on the left is, actually. I never bothered to care because I bought the engine hanging from a hoist and when I scraped all of the accessories off they went into a couple big boxes, and stayed there. Where they belong

If you eliminated the heat exchanger... hmm. See if the small blockoff plate (you're right on the large one BTW) goes on the doodad on the left, if it fits, great, if it doesn't, leave it alone and see if anything bad happens when you start the engine, like a vaccum leak. (Hey, honestly I don't know, I don't have manuals handy and it's been so long since seeing it hooked up properly that I don't remember)

 

Whoohoo, I hiope you can do it =]

116 pound computer nerd over here, who's planning on buying a racing beat exhaust within the next week =]

 

OK well I went to the Garage of Doom and unburied my stock '80 engine... the "mystery flange" appears to be the air line going to the heat exchanger. Air from the air pump goes in to the ACV, where it gets sent as necessary out of that flange to the heat exchanger, where the air gets heated up and routed into the thermal reactor. (Believe it or not this Mickey Mouse style emissions control works VERY well... on the engine's final emissions test it passed with flying colors, only 3.2ppm HC's! It couldn't cut the mustard for cold-start or NOx emissions, so Mazda switched to catalytic converters for '81, although I'm told some markets used a thermal reactor instead of a converter as late as 1986!)

Given what it does, it has a direct route to the ACV section of the intake manifold. I'm not certain about the '80 and earlier manifolds, but the '81 and later have a vacuum passage to the ACV area which is why you need to run a block-off plate if you eliminate the air pump, otherwise you can get a big vacuum leak. Likewise, you should have to block off that exit flange as it could potentially also cause a vacuum leak.

Or you could do what I did and spend a lot of time with the manifold on a bench, JB Welding that passage closed, and then using a Dremel and flap wheel to eliminate the leftovers that drool inside the manifold. I only did that because I was blocking off other stuff already (like the shutter valve shaft stuff which isn't in an '80 manifold) and I was too cheap to buy a blockoff plate. Given that you already have the blockoff plates, just use them.

 

Yes they fit in both of the locations, thanks much!

I did it, but my hands are all bit up and stuff, it wasn't something i'd want to do again

 

Yes that is were the block off plates go. the ACV and the little EGR