w208 CLK320 pattern cats

[reggie3cl]

Oh, I'm not happy. Seems like I've lost a second CLK to a dodgy cat (this time it/they have just somehow disintegrated and are cracked) and I only put two new tyres on it on Tuesday. Possbly the speed bump I crunched it on the other day, I don't know.

Anyway, do I scrap it or is there a pattern cat that actually fits? The car is a bit frilly around the edges, but is fully loaded and drives well otherwise. O/E will be more than it's worth.

And if it does have to go, do my Brabus wheels fit 209s?

 

[LostKiwi]

Hitting a cat will definitely do it no favours. M112 powered cars also have an issue with cracked cats anyway due to the way they're mounted.
One thing you could try is using mettalic cats as opposed to ceramic cats.
The metallic substrate is more resistant to impact and can cope with higher temperatures and are more resistant to thermal shock. You should be able to get s generic cat welded into the pipe.
Check out magnaflow metallic cats or http://www.bmcatalysts.co.uk for something that will fit.
Have a word with your local powerflow fitting shop too - they should be able to weld in a new one.

Almost certain your Brabus wheels will not fit a 209.

 

[reggie3cl]

Thanks for the info. My local Powerflow is actually in Turriff, so not very handy for me in Inverness unfortunately. My local independent doesn't like faffing around making pattern stuff fits, may have more luck at the garage where my suspension mounts were welded up earlier in the year.

Shame, I would like to get another year out of it (especially as I've done all of fifty miles on the new front Avons), but can't complain, I've had two years of fun for a grand...

 

[AMck]

A bit of a long shot, but there’s no chance it’s lpg converted is there? As you do not need cats at all then.

 

[reggie3cl]

No, it's standard. Having done a trawl it seems the sensible thing here would be to have the cats removed and a pipe put in their place - it apparently will still pass the emissions test come MOT time. I have found a mob in Elgin (about 35 miles from here) who look like they could do the business, I'll call them tomorrow and see what they say.

 

[LostKiwi]

That will work if you have primary and secondary cats but not if you remove primary cats.
The car has two sensors per bank. One before the primary cat and one after. The first sensor is used for fuel mixture control and the second sensor measures the health of the cat. If the primary cat is removed you will get an EML. If you only have 1 cat per bank you will fail your MOT.

 

[reggie3cl]

No, it would just be the two under the centre of the car - seems to have been done before by others. Reason I'm thinking of going with just a connecting pipe is that the speed hump I have to negotiate to get out of my street is brutal, and I will surely trash another cat on it, although I do take your pont about using a metal rather than ceramic cat.

There seems to be no requirement to have a cat, just to have the emissions right. If the primary ones are there I understand it will be OK. I imagine the car runs closed loop mixture adjustment so would adjust itself to run correctly.

 

[AMck]

Don't forget the new MOT. It might fail if examiner is aware some cars have been removed.

8.2 Exhaust emissions
8.2.1 Spark ignition engine emissions
8.2.1.1 Exhaust emission control equipment
This inspection is only for vehicles that must have a full catalyst emissions test (disregarding the basic emissions test). You only need to check components that are visible and identifiable, such as catalytic converters, oxygen sensors, and exhaust gas recirculation valves.

Defect Category

1. Emission control equipment fitted by the manufacturer: missing, obviously modified or obviously defective.

Major

1. An induction or exhaust leak that could affect emissions levels.

Major

 

[reggie3cl]

Do the new rules apply to ancient vehicles like mine?

 

[LostKiwi]

Do the new rules apply to ancient vehicles like mine?

All vehicles. Even my 25 year old 129.
It's only once they turn 40 and an MOT is no longer required they don't (but there are different rules for them).

 

[reggie3cl]

Hmm, well that sounds as though running a straight pipe is a non starter

 

[LostKiwi]

Hmm, well that sounds as though running a straight pipe is a non starter

You'll probably get away with straight pipes to replace the secondary cats as long as the primary cats remain. Most testers won't know there are normally 2 cats per bank. Just don't make it obvious something's been cut out and replaced with pipes.

A few SL owners have had secondary cats removed (including ours) and replaced by X-pipes but that's only worth doing on V8s (has virtually no benefit for a V6).
Those with secondary cats removed have had no MOT issues as far as I'm aware.

Your other option is to just break up the ceramic brick leaving the shell. I had to do that on my 129 SL when it blocked up until I could source a replacement as the car wouldn't run hardly.

 

[reggie3cl]

I'd have to find a new MOT man - my independent and my tester are one in the same, he'd notice! Wish I had an inspection pit, I'd have the buggers off and gut 'em.

 

[AMck]

I'd have to find a new MOT man - my independent and my tester are one in the same, he'd notice! Wish I had an inspection pit, I'd have the buggers off and gut 'em.

Why not ask him if he would fail it if it still has main cats, but secondary removed - nothing to lose.

I also had a V6 R129 where the secondary cats broke up. I had them replaced by a straight pipe, but I had no worries about MOT as mine was LPG converted. One benefit wasbit sounded nicer with cats removed.

 

[reggie3cl]

Yeah, will do. I don't know why I torture myself with these old vehicles (my much travelled BMW bike is 21 and my Laverda RGS is even more ancient at 32 years) but I do love 'em

 

[LostKiwi]

I don't know why I torture myself with these old vehicles

Because they have character and are fun

 

[reggie3cl]

Ain't that the truth. I'll make enquiries and post the results here.

 

[reggie3cl]

Have booked the CLK in to have the secondary cats removed beginning of September. My MOT bloke is more interested in the emissions than whether the zorst is standard. In the meantime I'll do a general tidy up while it's off the road - ran it up and down my (long) driveway today to clear the rust off the discs (wet after cleaning a whole heap of mud from the inside arch lips) and those cats RATTLE. Refinished wheels look cool.

In the mean time, have friends arriving from New Zealand, so it's off on the bikes to show 'em something of the Highlands

 

[reggie3cl]

Quick update- talked to my MOT guy and his main concern is that it passes emissions. Given what we found I think it will be fine. Cats were removed, turned out one was completely empty, guess the contents got spat out the back somehow, the other one was in bits. Car is no louder than standard (well, maybe a bit on kickdown) and is much smoother and of course the embarassing rattle has gone. Got 32.5mpg on the way back which is pretty good given quite a lot was down country roads. So, all good, she's driving lovely.