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Thread: Gutting MK3 Pre Cats & General Tidy-up

  1. #1

    Gutting MK3 Pre Cats & General Tidy-up

    Finally started this,

    If you are not sure why this is done have a google, there is some thought that when the pre cats break down the engine injests the bits and lunches the engine.

    Absolute doddle to remove the exhaust manifold (only took a few minutes), and only sheared one stud between the exhaust and manifold. Used a full hex socket on the manifold to head studs as they looked a bit suspect and will be replaced.

    On first inspection the pre cats dont look too bad, although one of them appears to have started to break down in 1 spot. Hopefully once removed the engine will be fine (at least until the project starts :thumbsup:)


  2. #2
    i should really do this on the wifes car but i am worried i wont get all the bits out and then cause damage with loose bits getting into the engine
    MK1.5 - fixed - turbo technics hybrid CT26, ST205 charge cooler, XS power manifold and decat (not split yet) air con to be sorted next

    Oh, and its now running thanks to Jiff and BSM

  3. #3
    Quote Originally Posted by rattymr2 View Post
    i should really do this on the wifes car but i am worried i wont get all the bits out and then cause damage with loose bits getting into the engine

    The bits come out really easy, all that is left is a little very fine powder that needs washing out. I will probably set the pressure washer on it before refitting. The removal and de-catting took me less than an hour, didnt even need to get the car up on axle stands. Removing the broken manifold stud took 2 hours though, and then there was the futher 1/2 hour looking for an m10 fine tap. lol

    One futher thing to note is that you need a split socket to remove the o2 sensors.

    Off to toyota tomorrow to get fleeced for a new stud, nuts & gaskets.


  4. #4
    Make sure your wearing your mask when you do this.

    as its really bad to breath in the dust, only causes cancer and gives you a horrid nasty dry cough..its worse than the dry sanding dust from outo paint

  5. #5
    Ordered new gaskets and replacement stud/nuts today so should be running again on thursday :thumbsup:

    Before I tackle the next job of sorting out the scabby headlights I thought I would price new ones up. Toyota want £103.42 each, certainly not cheap but cheaper than I was expecting.

    Finally I couldnt resist doing a little measuring, it appears from my rough measurements that the MK3 chassis rails are only about 40mm closer together than the MK1. Surgery will almost certainly be required but hopefully nothing too major. :)


  6. #6
    Parts arrived a day early :) car is now running again. Probably because I havent driven it for a few days but it seems to have a little more go now without the pre-cats.


  7. #7
    Removing a restriction is good!

  8. #8
    That was my experience when I did this on my first Roadster. Slightly gruffer note to the exhaust, but you might get a bit of boominess at certain revs, depending on what exhaust you are running. Some report they do, some don't.
    Good price on the headlights from MrT though. :thumbsup:
    Mk 3.6 V6 Roadster (sold) now a Mk 3 Roadster avec turbo!

  9. #9
    Quote Originally Posted by loadswine View Post
    That was my experience when I did this on my first Roadster. Slightly gruffer note to the exhaust, but you might get a bit of boominess at certain revs, depending on what exhaust you are running. Some report they do, some don't.
    Good price on the headlights from MrT though. :thumbsup:
    Its still on the standard exhaust, didnt notice any change in the sound.
    I may have a go at removing and splitting the headlights tomorrow for a clean, at least now I know how much it will cost me if I make a mess of them lol.


  10. #10
    If you split the headlights, you could always paint the inner surround, that is a pretty effective mod. Just heat the unit gently in the oven first to soften the sealant.
    There are records of this on roc I seem to recall.
    Mk 3.6 V6 Roadster (sold) now a Mk 3 Roadster avec turbo!

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