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MG MGF Technical - Will Munns - or anyone..

Okay, Don't kill me.. Just a question.
Is the 1.8 Cat the same as the VVC cat?

eeeek
Neil H

Pretty sure yes, but have you checked the heatsheild yet?

Will
P.S. I know you havn't! ;-)
Will Munns

No, I haven't... ;-)

Have I just got to check if its loose?

I'm obsessed that its the CAT because of the MOT near miss.., and the poor performance at the mo.
Neil H

after the car has cooled for some time,
lie on the ground look for the cat (behind exhaust, quite obvious), poke metal sheild (towards front of car) to see if it's free'ish, if so then start car and push/pull the metal to see if it will touch cat, if it does then this is your problem.
Will Munns

Neil, I suspect that your cat is fine - at the MoT either the catalyst wasn't up to temperature, or the car is running on the rich side for some reason (which may also explain the poor performance)
Rob Bell

I missed the other thread (apparently) so I don't know if this has been said or not, nor do I know what car version you drive (pre-OBD2 or not)

- Faulty lamda sensor might be your Problem. This could explain bad performance and Emission troubles.
T

Thanks Guys.. - well tomorrow I will know when I take it all apart.., but the update is that on the motorway this morning I really noticed a total lack of performance and acceleration.
Then, getting onto the A-roads I tried to give it a squirt in second gear.. When I get above 3,500 revs you can hear a whistling start to build up..

I am pretty sure its my cat.. It has blocks inside and I think one of 'em must have moved and blocked the free-flow of air.

It adds to the other symptoms of bad CO, but not HC and it sounds like a biscuit tin full of marbles in the mornings.

Any suggestions what else would do that?
Neil H

If you remove the CAT and give it a light shake you will soon tell if the honeycome internals have started to beakup. If this turns out to be your "biscuit tin full of marbles" you will know what the problem is before you commit cash to buying any thing new.

If its just a loose CAT heat sheild that will be very evident too.
Steve Ratledge

Well, on my desk next to me, I have a lovely CAT bypass courtesy of the life-saving Victoria herself!

I'll fit it tomorrow, and inspect and test the rest.
If it were the heat-sheild, then I must have something else rather nasty wrong too - because of the performance issues.
Neil H

I hope that you have all the stud nuts soaking in penetrating oil Neil - they'll be a pain to remove otherwise. I'd also recommend a 6-point socket - the usual 12-point socket will more than likely round the nuts off...
Rob Bell

Yeah. Good call Rob.
I have been dreading that bit.

First thing I'm doing when I get home is introducing the nuts to a load of WD40..
Hopefully they'll shift tomorrow.
Neil H

PlusGas is much more effective than WD40 (see halfords)

Also whilst a 6 point socket is good, a more expensive socket one will drive the flats rather than the corners, so they are much better at not rounding the nut (look at the inside of the socket, they tend to have rounded lobes and fit losely on the nuts.)
Will Munns

Rob - Do you know what size the nuts are?
Neil H

17mm. A deep socket is very useful.
Steve Ratledge

Cheers mate.. A trip of Halfrauds on the way home me thinks..
17mm, 6-point deep socket.

Anything on the other side?
Neil H

The is a nut on one end of the thread. The other end is a captive stud. When you come to fit the CRP (CAT Replacement Pipe) you will find it very handy If you have bought a set of 6 stainless steel nuts and bolts. I think they are M10x55. Also get 12 washers to fit.

If Halfrauds don't do them. Most big DIY stores do.
Steve Ratledge

PS: there is a thin metal gasket at each end of the CAT where it butts up to the exhaust. They are reuseable IF you are caeful when you take them out.
Steve Ratledge

You're a star Steve.. Thanks.
Neil H

How did it go? Still got skin on your knuckles?
Steve Ratledge

Hopefully the studs didn't shear off as happened on my car the last time I replaced the exhaust... :o/
Rob Bell

Morning,

Well, it wasn't easy!
Covered the nuts in WD40 Friday night.
Couldn't shift them for love-nor-money on Saturday!

(Oo! Whilst I remember.. for anyone reading this in the archives.. its a 14mm deep-socket)

Eventually went to an exhaust centre where some young lad used gas to burn two of the nuts off (took over an hour and a half) before he ran out of gas.
Went to a second centre, where some (slightly brighter) lad used that pneumatic socket thing and just un-screwed the other four them with ease in about 1 minute!!

Anyway.. the CAT's off and was knackered.. Lots of broken bits rattling around.

Fitted the bypass pipe..
Now, no-one told me it would be as good as it is.
The car seems a million times quicker (but I will be biased as I've been driving a car with a broken cat for weeks/months!)
More importantly.., the car sounds exactly the same as before... until you press that right pedal..
Then you get a lovely WHAAAAAAAARRRP as you accelerate away..

Love it!






Neil H

LOL! Nice one Neil :o)

Might be an idea to pick up a spare cat for MOT time! :o)
Rob Bell

I bought a spare CAT from BM Catalysts for 95 notes. - very good price.
It arrived this morning.., but now that I the bypass, I can't see it making it as far as my car until MOT time next year.

Neil H

This thread was discussed between 29/07/2004 and 02/08/2004

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