...whether or not I MUST remove the ACV and airpump. I ordered the full dual-pipe exhaust from MazdaTrix, but they did not include the plate and gasket for blocking the ACV opening in the intake manifold. I have no metal-working capabilities, so please don't say "who knows if its necessary, just whip one up anyhoo and...".

The car is an '80, but does not have reactors. The engine was swapped at some point, and from what I can see, has some Midas-looking hack-welded jimmy-rig back from the exhaust manifold. Hopefully, all of the original hangers are unmolested, or I'm going to have a hard weekend...

Thanks in advance.

 

Order the $10 worth of block off plates and remove the airpump. Normally I Would advise not to buy something this simple but they are cheap and very good quality. Sheetmetal is too thin I think to cover and the rb plates are very thick. You couldn't get them made for the price unless you ordered 1000 of them.
You could always bend the pipes shut and go ahead and install the exhaust, the choise is yours.
Being in WA it shouldn't take too long to get them If you call in the order.
Good luck with your exhaust, you're in for a real treat the first time you fire it up. (assuming there's no leaks, which I always run into even when putting in rb stuff)

 

Hmm. I will be removing the airpump and ACV in the future, most likely when I upgrade the intake to either RB's Holley intake or Sterling's carb mod. What I really want to know is, lacking the block-off plate & lawnmower belt, is there a functional reason for not installing the exhaust this weeked? Meaning, will it be safe to run without having done these mods? I'm unclear what the negative effects are of having a non-functional ACV and airpump installed (yes, I'm aware of weight. No, I don't care. The car is 24yo, and not whipping anything off the line).

BTW, RB "suggests" using high-temp silicone sealer on all fittings when installing. I assume that translates to red RTV--am I wrong?

Thanks for the reply, jorx81.

 

Install your exhaust!

Since you are not going to have cats and you said you don't have them now, you have no need for the air pump, don't be afraid to take it off. You don't need the lawnmower belt either, your exsiting belt will work fine assuming it's in good condition. I wouldn't put any rtv on the exhaust if that's what you mean, just get the rb gaskets if you don't already have them.

 

Exhaust installed. For those who happen to use the search function at some later date, I would advise getting exhaust hangers from Victoria British. They are $5 ($15.64 @ Mazdatrix). I am going to order 4 for my '80, which has 2 holding the rear of the muffler, 1 at the front of the muffler, and 1 in front of the rear axle. They are all rubber pieces that hang from a point on the underbody, and like all rubber pieces, age poorly. I had 2/4 broken, so I must venture under the car again this weekend if the shipping is fast.

I didn't use any RTV, as I couldn't find any with what I felt was high enough heat tolerance (>700F). Which wasn't a bad thing, as it would have sucked trying to keep the RTV from smearing whilst balancing the centerpipe on my knee, because the hangers were gone.

Put anti-seize lube on all nuts & bolts during re-installation. This will make later projects easier. On a related note, it helps greatly for removal to have the car up on stands overnight, with penetrating oil working it's magic. I used 2 applications on Saturday night, and had no problems with any nuts/bolts on Sunday.

Lastly, Racing Beat and Mazdatrix do not include ACV/EGR block-off plates with the dual-pipe exhaust system for the 12A. This is because the system can be installed on '79-85, which includes at least two different ACV sizes, apparently.

 

Forgot one important note: with the dual-pipe system and broken hangers, I had to install the header first, and then the centerpipes. This is rather difficult to do, as at least 1 of the 6 bolts mating the two surfaces has no easy access. I used a socket U-joint (wobbler? unsure of nomenclature) in tandem with a wrench that did the trick eventually, although I had to re-tighten once to eliminate a leak at this joint. Assuming all the hangers are good, you should be able to assemble the centerpipes and header on the floor, and install as a single unit. Two people would be nice with either route, as the centerpipes are heavy enough on their own.

 

Yep, two people were necessary on a friend's '81 with the dual pipe system. I guided the header onto the engine while the other guy lifted the centerpipes. It worked pretty well even with an Atkins 5" SC installed.