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Discussion Starter #1
First post for me here. Been a member of MR2OC for a few years, had a 87. Now I have a 2000. Doing a tranny replacement. Its been growling for a while, but got REALLY noisy on the way home Friday. i had picked up a low mileage tranny a while back. Stupid me, I did not get clutch, pressure plate, bearing, seals, ahead of time, now I have to wait.

I need to do a pre-cat delete. The bolts holding the heat sheild are rusty beyond wrenchable. Gotta drill em out :(
My question is, do I need to drill the bottom ones out to get at header bolts? Hopefully not.
 

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Here is the Che header. It has the same 4 bolt locations for the heat shield. Maybe you can snap it off without drilling the bottom 2.
 

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Discussion Starter #4 (Edited)
Thanks for the replies.
Yes, I found that there are 2 other bolts to be taken out (probably drilled). They are really not accessible until the muffler AND cat are taken out. When I took the bottom piece(cat?) out, the jack holding up the engine tipped, and the engine was hanging by only the top mount. Now I have to check for collateral damage. I didn't see anything obvious yet.

I see up the into header, and the honeycomb is intact - good. Can I just punch through from the bottom without removing the header?

EDIT- Nevermind. I just read the "how to do pre-cat". It needs to come out. What a PITA. But, replacing the engine and cat is more of a PITA.
 

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I see up the into header, and the honeycomb is intact - good. Can I just punch through from the bottom without removing the header?
Some have done this. Personally, I frown on the procedure. In my write-up of "how to decat," I recommend removing the header completely, knocking and drilling out the precat matrix, then flushing out the header with water and power drying it with compressed air.

If any remnant of the ceramic particulate remains in the header, you may actually initiate damage as a result of the procedure so want to be absolutely certain you've got that stuff out of there.

That said, some have decatted from the bottom, and if you're meticulous you might be able to get a good result from this.

On the other hand, getting the header off will allow you to treat all bolts, nuts, and studs with anti-seize compound. You'll get to replace the manifold gasket, and generally get everything ship-shape and tidied up.

While you're at it, get some convoshield wire dressing to protect your O2 sensor leads, and paint the main heatshield.
 

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Discussion Starter #6
Thanks for the response again.

I got the header off. Now to order all my parts ASAP and gut the header.

Paint the shield? After 12 years, will the paint stick OK? I suppose a black (gloss?) to match the car would be good, as long it would stay put.

I don't know how many people remember the kid's song " I remember a lady who swallowed a fly...". This job kinda remind me of that. I gotta replace the tranny. Might as well get to the pre-cat, seeing as the axle is off, get better access. Well, gotta remove the mufflers to get the bolts. Gotta remove the taillight to get the O2 sensor wire (no O2 wrench). Gotta go get an O2 wrench to get the sheild off...

BTW, it took me all of about 5 minutes to remove the whole exhaust of an MKI.
 

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I recently repainted my heat shields with aluminum high heat paint. I like the way they came out. Just make sure to remove all of the rust, (I used Naval Jelly Rust Dissolver), and lightly sand the whole shield before repainting it. I did both sides.
 

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all you have to do is pull the o2 sensors off and take out the top heat shield bolts to get the top heat shield off, like maybe five minutes. I did mine in silver and got new bolts for the top heat shield and it looks 400% better.

And to anyone else that has rusted tight bolts that wants to do a precat delete, i'd shove a rag (like thin t-shirt material) into the o2 holes to block the ceramics from going back the wrong way, then once the bulk is out from the bottom shove the rag back past the o2 sensors from the bottom before washing and blowing it out. I wouldn't want to risk the pre-cat material from going into the block in any way.
 
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