In my two FB's the shutter valves are messed up.

I used to have a pic of me pointing to the passage in the air cleaner that one should block to eliminate the vacuum leak caused by the malfunctioning shutter valve.

This works just fine on street driven cars with mild backfiring.

I don't believe that's allowed in Spec RX-7 in which case I'll have to repair it.

I've never seen a repair for this, only workarounds like plugging the vacuum line to it, removing the valve and filling in the irregularities in the manifold with JB weld, or swapping in the 78-80 manifold, all of which are illegal.

Suggestions?

 

Mazdatrix.com has a detailed explanation of how to fix it, online. I've not done it yet, but it looks like the hard part is detaching the carb with some warped up box wrenches.

 

There is no known repairing of the shutter valve. You have to replace it.

 

part number is n238-13-130 or 1480-13-130A

gasket is 1480-13-139b

 

Not hard at all to remove or repair, not sure on the cost of the valve itself... too bad you have to keep it, it does nothing as I've passed smog several times with both 83's and they have it blocked off...

 

the only place ive seen it explained is in the "rotary engine" book by kenichi yamamoto. basically it keeps unburned fuel out of the cat, and thus keeps the cat temp from spiking on decel....

thats it. the spike was big, but how many of use even have cats?

 

Hmmm, interesting, never heard that before, although it does make sense. I run one main cat behind my racing beat header, and it has notably deteriorated (exhaust has begun to smell more and more) might explain why... Oh well all my 12a intake manifolds are minus the shutter valve, not like I'm gonna put it back on.

 

Running a Cat without having the air pump on is worse for the car than not having a functioning shutter valve.

 

yea that I do know for sure. The shutter valve is the only part of my emissions equipment that isn't there (mainly because it was broken and making the "honking" sound) Everything else is there and functional. either way it was a $30 catco cat from ebay, so if it burns up its no big loss, inspecition is 2 years in NJ, so I'm good till early 2008

 

thats another good point, the cat was $30, the shutter valve lists for $104.30....

 

That and the fact that the 12a will be gone before the inspection sticker expires makes it a non issue....