De-Catting and the MOT

[Anonymous]

O.K. I'm thinking of gutting my precats this easter but am worried that if i do then i will fail my MOT emmisions test. Anyone here know for sure whether it would be o.k? What if the engine is cool (when the precat is important) will it still pass? If the answer is YES why did toyota include the precat to begin with  s:? :? s:?  

I think alot of people will benifit from this question being answered.

[aaronjb]

Yes, it will still pass just fine.

The precats are there in order to make the Mk3 a ULEV (Ultra Low Emissions Vehicle), which is - if I recall correctly - not a standardisation we have in this country (I seem to remember it exists only in the US and mainland Europe).

The MOT test is meant to be done (if memory serves) on a warm engine anyway.

People have even been able to get cars to pass with no main CAT (albeit by creating very conservative fuelling maps just for the MOT I believe  s:) s:) ).

Anyway - in short - junk 'em, unless you live in the US or another country that has ULEV testing (Germany? Sweden? Finland? (Tem?))

Aaron

[Anonymous]

Cool thanks, that is just the informative answer i was looking for! time to get me screwdriver and hammer  s:twisted: :twisted: s:twisted:  

Anyone okow id the Whole cat container (baked bean can) is fill of homeycomb or just a thin mesh  s:?: :?: s:?:  

Not than it matters, i will report my sucess or demise for others  s:wink: :wink: s:wink:

[aaronjb]

I've not attacked my own header (yet!), but based on what was inside the precats on my 300ZX..

You'll find each can (there's two on the header don't forget) will be full of a catalytic honeycomb (looks very much like the inside of a Crunchie  s:D s:D  ) 'suspended' between two sets of wire mesh..

Attack with a giant screwdriver/crowbar/'kinooge drill/pliers etc till it's all gone.

I'm guessing most of it will have to come out of the 'bottom' of the header (i.e. the end that connects header to main CAT, rather than the end that bolts to the engine).

Oh yeah - you'll probably want to remove the O2's from the manifold to avoid damaging them too btw..

Think that covers it, from memory  s:) s:)

[Anonymous]

would someone like myself - i.e with no real experience of working on cars, be able to do this? would love to see a step by step instruction guide   s:wink: :wink: s:wink:  

by the way, managed to remove the mid section (elbow) of the air intake in 5 mins so i cant be that useless!

[markiii]

if you can fget the manifold off, yes.

I reckon you would need.

02 sensor removal tool, approx £6
socket set
scredriver

and some means of getting under the car, be it ramps, jacks, or just that quite thin.

easy really. If in doubt, perhaps someone close to you would offer a hand.

[Anonymous]

yeah that was my main concern too about the manifold. Are they awkward to get off? i suspect its a pretty easy job when you do get it off, just knocking out the honeycomb.

[markiii]

wd40 every bolt you can get at a couple at day intervals for a coupl eof days before hand and it should be reasonably easy.

If you really worried about breaking something, ask your local quick fit for a price to remove and re-atch your manifold.

spend 30 mins in between in their carpark with a screwdriver and then get them to put it back.

if they shear anything tnen it's up to them to fix it.

[DAZ400]

I suggest using an ordinary 22mm ring spanner to remove the O2 sensors as the connector passes through it. I have found the special O2 sockets useless as the O2 sensors are generally bloody tight after been in a while.

And make sure you squirt every nut and bolt you are going to undo with WD4o and leave for 20mins it will help lots.....

Good Luck.....  s:roll: :roll: s:roll:

[Anonymous]

Also before you start, run the engine for a while get it hot. Start work when the temp is enough you don't get burnt. A warm nut is an easier nut.

[Anonymous]

mr-s turbo, have you done this? reason i ask is because you have a turbo which would invalidate your warranty so you have nothing to lose

[markiii]

a turbo necessitates a replacement manifold anyway, which doesn't have pre-cats.

So I suppose he has removed them but only because it's a different manifold.

[Darth Paul]

OK. I gotta ask. I'm a complete numbnuts when it comes to anything engine-y. Why would you do this. Performance increase? More noise? To more rapidly deplete the ozone layer? And what do your insurance companies say? "Sorry, sir. You've done what? I see. I'll just consult the check-list... No sir, it would seem that that isn't covered. Sorry, you've done what again?" And what about the warranty? Wouldn't it affect that? Couldn't Toyota say that doing this caused engine damage?  s:? :? s:?  

As I said, I know $hit. Please explain!  s:lol: :lol: s:lol:  

DP

[markiii]

Insurance? well I suppose technically you shoudl advise them, but you've not actually added anything? Woudl I tell them if I removed teh radio?

teh weigth loss may make it faser so should I?


as to why we've doen it do death in other threads lately but in short.

if they aren't there they can't fail, if they can't failthey won't take your engine with it.

You may see a very small difference in sound or power, but they main reason is preventative maintenance.

The main cat will still be there so it will make preciosu little difference to teh environment. It could make a very large difference to your bank balance.

[Anonymous]

its to stop all these engine failures. *Cue technical voice* what happens is the honycomb in the pre-cats disintergrates over time and then gets sucked back into the engine - which isnt good.

[markiii]

oh, and if you wait til your out of warranty, frankly who cares what Toyota think about it causing damage to teh engine, it won't  but even if it did they wouldn't be covering it anyweay.

[Darth Paul]

Gottcha.

[Tem]

Also before you start, run the engine for a while get it hot. Start work when the temp is enough you don't get burnt. A warm nut is an easier nut.

I actually did that right after the drive, when everything was hot enough to cause burns...and I've done it several times before. Just don't be under anything, cause even the dirt is bloody hot. And use thick gloves.

That way the bolts weren't even tight, even after about 20 years of being stuck and getting rusty and salty, they feel like someone just tightened them by hand a minute ago.


Oh and you can remove the manifold from above, there's really no need to lift the car or get under it...it's a bit tight though, so might be easier from below.

[Slacey]

Who's up for a gutting party? I'm really tempted to go for it but would probably need some mechanical assistance.. I could try the Kwik-fit thing though I suppose.

[markiii]

I'm not driving all round teh country, but if you can get every one in teh same place  :-) :-) :-)

[Slacey]

I'm not driving all round the country, but if you can get every one in the same place  :-) :-) :-)

I thought that if I was subtle I would get a response  s:wink: :wink: s:wink:  

We'll have to get something organised.

[Anonymous]

id be up for a meet on this one.

and maybe someone could help me fit my springs aswell   s:wink: :wink: s:wink:

[Liz]

Me too, I want to gut the cats  s:twisted: :twisted: s:twisted:  , warranty up on the 10th April, got MOT so I don't care anymore, anything to prevent engine ka-boom!! Got quite alot of time off in April so let me know a date if you guys get this organised

[Anonymous]

Can I join the party too.

It would be good to meet some people on here.
I always seem tied up on the other meet dates.

Ian

[SteveJ]

A word of caution ref: squirting WD40 on the exhaust manifold - make ABSOULTELY SURE that you do NOT get any WD40 near the O2 sensor, as it is a synthetic lubricant that contains silicon, and will DESTROY the O2 sensor - the sensor has an opening to allow outside air to get to one side of the sensor element and silicon is poisonous to the chemical reaction that takes place within the sensor.