Pre-Cat de-cat time

Optimus Prime · Post by **Optimus Prime** » 27/07/18 12:37

Hi Guys,

I'm going to (re)tackle the pre-cats soon. the 4x heat shield bolts are well and truly corroded. I've sprayed a load of plus-gas on them, filled them down, knocked a socket on them and they just won't budge without rounding off the heads.

Does anyone out there have any advise on the best way to approach this?

I was thinking of dropping the main cat and pulling the pre-cats out of the Manifold but i'm really concerned about leaving debris in there, needless to say I soon turned off that idea.

Any help would be great.

Cheers,

vinp182 · Post by **vinp182** » 27/07/18 14:16

Grinder or dremel

Optimus Prime · Post by **Optimus Prime** » 27/07/18 14:19

I did think about that but if I grind the heads off I wont be able to get the bolts out... or am I missing something?

MRHAPPY62 · Post by **MRHAPPY62** » 27/07/18 16:15

yes once the manifold is off, you drill out the old bolts and retap the threads.

Optimus Prime · Post by **Optimus Prime** » 27/07/18 16:26

I've never drilled and re-tapped into cast iron with a hand drill before. I've done it on an aluminium block with a drill press and that was a piece of cake... I suppose it's time I take to youtube and check out how to do it.

Cheers,

M07775 · Post by **M07775** » 28/07/18 10:52

Sorry to kidnap this thread but has anyone got a garage to do this work?

The garage I used on a regular bases won't do it, I have been told it is a much faster job with an access to a ramp.

MRHAPPY62 · Post by **MRHAPPY62** » 28/07/18 15:18

Maybe if you put your location up , you might get an answer !

Optimus Prime · Post by **Optimus Prime** » 02/08/18 9:14

I have another idea! rather than deleting the cats from this manifold should i just buy a performance one such as this: https://mr2-ben.co.uk/products/649
I could then sell the existing manifold with the cat's intact.

Do you think I would get any performance increase from deleting the existing cat's or would i yield much better results with an aftermarket unit?

je72 · Post by **je72** » 27/08/18 17:22

I got mine decatted at Mr Twos in Willenhall, West Mids:

http://www.mrtwos.co.uk/contact_us.htm

£50 all in, done in about an hour and a half (just time for a full english brekkie in the town)

cookie.cc22 · Post by **cookie.cc22** » 11/03/19 11:38

I have a 2002 MR2 mk3 with 73000 miles on the clock, can anyone advise me when I should consider having the pre-cat's done

vinp182 · Post by **vinp182** » 11/03/19 11:40

cookie.cc22 wrote: ↑11/03/19 11:38 I have a 2002 MR2 mk3 with 73000 miles on the clock, can anyone advise me when I should consider having the pre-cat's done

Ideally 73000 miles ago. Get it done ASAP dude

carolineasb · Post by **carolineasb** » 11/03/19 17:41

You may wish to just swap for a precatless manifold rather than bashing them out. If you do bash them out, please make sure you wear lots of PPE :(

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