CLK MOT pass with 2 cats removed

[television]

Actually it was a girl trying to claim child benefit in the USA that reminded me of this.

When asked by the judge who the father was, she replied "its like bake beans your Honour, when you are eating them, you do not know which bean made you pass wind, do you"

 

[Adam230K]

This is a great thread, but i have a question.

From what TV and LeighW have said, you can removed cats (not all of them, just one) and get away with it at MOTs. I'm assuming your cars have 2 cats just because they're V-engines.

So when i cut the cat open like a tin of beans, what am i actually emptying? bits of metal.. or what? shed some light please

 

[television]

Cut the bottom open with a angle grinder, inside there is a white honeycombe, it ceramic and powdery and can be pulled out in one lump. Its on a par with plaster

 

[Bobby Dazzler]

This is a great thread, but i have a question.

From what TV and LeighW have said, you can removed cats (not all of them, just one) and get away with it at MOTs. I'm assuming your cars have 2 cats just because they're V-engines.

So when i cut the cat open like a tin of beans, what am i actually emptying? bits of metal.. or what? shed some light please

I think when people refer to removing a cat, they're usually referring to engines fitted with two catalysts in sequence - a primary and a secondary cat.

It's the secondary cat that's removed, leaving the primary cat in place in order to ensure the car passes the MOT.

With a modern V engine, they have four cats - a primary and a secondary cat for each bank of cylinders.

When you open it up you may have some bits of metal, but more likely the core will be ceramic. Some do use metal foil, but I think the OEM one is more likely to be ceramic and hence the reason why they can "break up" and rattle.

 

[bolide]

I wonder what the effect would be of removing the cats on an E300 Diesel?

Nick Froome
www.w124.co.uk

 

[Bobby Dazzler]

Is yours a turbo Nick?

I once read that turbo diesels respond well to removing cats, making them more willing to rev, and boosts low down torque even further - presumably the turbo spools up quicker.

Why not do an experiement in the interests of science!!??

 

[bolide]

No turbo in an E300 Diesel. Just wondering what difference it'd make

Off-topic I drove a 203k-mile E300 Diesel this morning. It went like a rocket - much quicker than my one! The way they spin up to 4500-4700 rpm is amazing for such a big old engine

Nick Froome
www.w124.co.uk

 

[maddog]

I removed the secondary cats on my e320 cdi and yes the car spools up quicker , i also removed the cat on my Nissan Skyline and with no cat its gone through the last 3 mot's without problem

 

[supercharger]

great source of info this thread. so can any of the experts on cats and co2 and all the other gubbins that comes out the back of our motors advise me on the outcome of an mot on my w140 s500 1994 vintage im told it was originally fitted with cats but the cats were removed last year prior to me purchasing the car as they were breaking down.the car passed its mot before i purchased it so is it likely to go through the test without problems this coming october.

supercharger

 

[television]

great source of info this thread. so can any of the experts on cats and co2 and all the other gubbins that comes out the back of our motors advise me on the outcome of an mot on my w140 s500 1994 vintage im told it was originally fitted with cats but the cats were removed last year prior to me purchasing the car as they were breaking down.the car passed its mot before i purchased it so is it likely to go through the test without problems this coming october.

supercharger

Yes it should go through the test OK,, Most MOT station will test the Co output for a small fee

 

[GazCaff]

I wonder what the effect would be of removing the cats on an E300 Diesel?

Nick Froome
www.w124.co.uk

My C250TD has passed its MOTs without a hitch in spite of having no Cat. Then again, you might as well stick a sieve on the end of your exhaust for all the good a Cat does on a diesel.

 

[Dieselman]

. I don't live in a city, and believe me, the buses used by the local companies are far from state of the art.

Leigh, it's taken me ages to find this post of yours as I took a couple of photos of a typical 'Bus from your town' when riding home from the peak district last October.

As you can see it's an old smoke belching clatterwaggon..

See the smoke as it pulls away...

Saw another interesting vehicle there as well....

I'm sure you'd look good in green......

 

[Bobby Dazzler]

"...cleaner that a nun's thoughts"

 

[LeighW]

Leigh, it's taken me ages to find this post of yours as I took a couple of photos of a typical 'Bus from your town' when riding home from the peak district last October.

As you can see it's an old smoke belching clatterwaggon..

That's not my town, but thanks anyway.

Edit to add that I was talking about the late '70s double deckers taking the kids to school that I regularly follow in a morning. Anyway, back on topic...

Also, the Prius isn't anywhere near as 'green' as it's makers claim, it's 'real world mpg' is sub 50mpg, hardly groundbreaking.

 

[C240Sport97]

Don't forget the toxic nasty stuff used in making the batteries, and the disposal thereof.

Prius is a con unless you do lots of town driving.

Also, the Prius isn't anywhere near as 'green' as it's makers claim, it's 'real world mpg' is sub 50mpg, hardly groundbreaking.

 

[supercharger]

i deliver cars all over the country and only last week delivered a brand new prius to a gentleman in london i took it from derby to dagenham it had minimum fuel on departure (3 miles on the clock) i put £30 in fuel in it and the light was on when i arrived. as you say leighw hardly ground breaking. also just to had it was one of the worst cars i have ever driven a truly awful experience, as i say i deliver cars from both ends of the spectrum and this was awful.


supercharger

 

[Dieselman]

Also, the Prius isn't anywhere near as 'green' as it's makers claim, it's 'real world mpg' is sub 50mpg, hardly groundbreaking.

I actually agree about the Pius..Oh, no that should be Prius..

Good job it's not one of those then..

 

[CLK 320 AMG]

Yes sudden cooling has always been a given reason for cat failure. I imagine a lot of drivers having problems after the widespread flooding this year.

Yeah I just flooded my engine Never mind I've got a new CLK 320 on the drive now :bannana:

 

[television]

In my 129 I reversed onto a grass verge to let a tractor pass by,, that cost me the Cats and I got the dreaded tinkle sound

If you cool the outside before the ceramic CAT has cooled it crushes it,

2 hours later they were cut out and I was ½ cat free and it passed the MOT with ease

 

[fredfloggle]

A big reason for failure is parking or driving through long grass. The outer casing cool down faster than the ceramic inserts,crushing them in the process .
I reversed into a farm track with a grass center to allow a tractor to pass, when I drove away tinkle tinkle and that was that,take them out or £1500 for new ones

Whilst I don't doubt that thermoshock killed the CAT, it is almost certainly not caused by the casing contracting and squashing the CAT. On start up if that were the case the matrix would expand much faster than the case , especially once the CAT "lit up" and would therefore crush itself .
Notwithstanding that the coefficient of expansion of the case and the matrix is miles different, and the matrix is bedded on a compliant blanket.

Grass is one thing, but wouldn't the CAT's die every five minutes in the rain that the UK has?