so i was trying to take of the stock cat and i think i may have stripped it... (not the spring loaded one, the one closer to the front of the car... anybody have any suggestions? my friend reccomended drilling it out then replacing it with new bolts... is that logical? also are there specific bolts i should get to replace them or are the a universal fit?

ps what gaskets do i need... i know what they look like but i dont know the technical term or size... (rx8store resonated midpipe)

-benny

 

page down to "Exhaust System Hardware"

http://mazdatrix.com/8exhaust.htm

 

Are you talking about the connection between the downpipe and the Cat pipe? If so, only one side of the bolt is designed to turn. The other side has spines on it so that once they are tightend they don't come loose.

 

if its the threads just use a die from a tap and die set or buy a heli coil kit, either may work.

 

rx7.com also has them.

 

when i was taking those bolts off, one of the nuts stopped spinning and snapped off with the threads. luckily i had enough thread left to put another nut on. Good luck on your install though. let us know how it goes

 

On brillo's car, when we pulled the cat off for the first time, a bolt stripped like that. It's weird that it can do that when taking it off. If you don't have the nut all the way off, you can actually force it off. Getting it back on will require one of 2 techniques. 1 is that you use a die to rethread the bolt but get a new nut. The other is that you pound out the bolt since it is pressed in and get a new one from one of the above sources. Find a new nut. I've actually just gone to a hardware store and found hardened bolts and nuts and used them before. All that matters is that they work. It doesn't matter if it's a Mazda bolt or not.

 

it because it's stainless which has a tendency to gall anyways but with the rotary heat it's almost a certainty. Always use high heat anti-seize compound when doing the re-install, it helps a lot

http://www.neverseezproducts.com/purenickel.htm

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When I was taking off the stock cat one of the front bolts was completely stuck. I tried and I tried to get it off and eventually the bolt just broke in half. Never did get that nut off of it.

 

I did the same thing my self and i just orderd a new one from mazda

 

I just drilled the stock cat and used cheap bolts. Anti-seize is nice, too. I would recommend some split washers to make sure the bolts dont back out. That may not be necessary, but I cant see a downside.

 

Does anyone have the actual size of the studs? I read somewhere that TeamRX8 mentioned 10x30mm for the manifold side bolts. As far as the exhaust side studs, what did you guys use? I would think that the studs and springs/nuts provide some flex and prevent overtightening and crushing the donut. Is it possible to remove the stock ones, and if so, how?

I used some off the shelf bolts and I either have a leak or I have the pipe coming in contact with the crossmember, because I have an awful sound at 4k RPMs (+/-). At least, that's what I'm hoping for. I hope it doesn't always sound like that. Outside of the 4k RPM noise, it's a little louder, but not quite obnoxious (Resonated mid with stock exhaust).

I'm trying to avoid having to order them, and my local dealer can't find them in the system.