Damned Catalyst in the way!!!

[sadgoth]

Help!

Right, Alistair (S2000) & I were all up for replacing the exhaust from the manifold back, sounds easy? yeah right, most of the bolts have seized, had to cut the old pipe several times, fine no problem. Got the to downpipe with a bloody big cat on it (remember this is a US spec gen1), because of the shape, you can't get to the supporting bolts on the cat, ok so we try and take the inlet manifold off, the bottom left hand bold is completly in accessible because of the cat, so far we are halfway through cutting the cat off with an angle grinder, which still takes ages, Mazda must have been having a laugh when they built that cat it's made of something like 5mm steel! Does anyone know any tricks for getting the thing off??? Otherwise I can see this exhaust change taking weeks.

cheers

Mark

[MikeLMR]

the US guys are always beefing about that bolt ... I think they use a cut down socket + a universal joint to get to it.

can you not just grind the bolts off holding the cat to the manifold section ?

[sadgoth]

could do that with the top ones once the inlet manifold is out of the way, don't think u could get a grinder into the gap on the underside of the cat!

Right pain in the you know what!!!

Anyway, rain stopped play today so it'll have to wait till next w/end now!

[sadgoth]

Also, does anyone know what the pipe is that runs off the back of the inlet manifold into the exhaust? I suspect it is cat related but once you have taken the cat, air pup and other bits off, you'd have an open inlet into the inlet manifold which can't be what the doctor ordered!

[Cycaduk]

Hi, I have just done the same with my gen 1. Used a socket and universal to get that nut off, but also started with the engine warmed up, then allowed to cool just sufficiently to touch. If you are talking about the pipe that goes from the rear most part of the inlet manifold, it appears to carry hot air, that had previously been used to cool the catalytic converters, into one chamber of the inlet manifold. There is a valve in the manifold that appears to either direct this air into the exhaust ports of the engine, or back down the small bore pipe that runs alongside the exhaust. (I might have these round the wrong way.

You can make up/buy blanking plates for these bits if you are getting rid of the airpump etc.