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MG MGF Technical - Farting Exhaust?

Hi All,

Just after a bit of advice please. I've got a 99 VVC with approx 30k and have noticed a bit of a problem.

During cold starts the right hand exhaust makes a loud 'farting' noise and I can also hear a sort of hum from inside the cabin. This is especially noticable when the clutch is pressed and when accelerating away in first gear. Once the engine has warmed up a bit, the 'farting' noise from the exhaust and clutchy hum is not audible.

Any ideas anyone?

Thanks again,

si.
Si

Odd,

The MGF does make the odd pop and crackle when cold (especially at low revs in gear down a slope), certain sports exhausts accentuate this, my MS Daytona one does and the SP / Miltek one really makes the most of this characteristic.

If the noises are not pops and crackles then it could be a blown exhaust, especially as it appears to be coming from one side only. However, i can't see why it would dissapear when the engine warms up. I doubt it has anything to do with the clutch though as the gearbox is mounted on the petrol tank side of the engine inside the bell housing, therefore it is not anywhere near the cabin (the gear stick is remote from the gearbox and controls a cable linkage).

Anyone else got any ideas?

SF
Scarlet Fever

After replacing the HT leads with Magnecours from Mike Satur, my exhaust no longer splutters and there has been a noticable improvement in starting and general smoothness and throttle response.

Unfortunately the original exhaust and catalyst remain fitted (though rusty) due to passing the MOT emmissions test again.

Thanks to the BBS archive - I have sealed up my spilt catalyst heat shield with exhaust putty.

Jon Baker

Thanks for the advice from both of you. I guess it could just be the case that the exhaust needs replacing. The car sounds more like a diesel than a sports car at the moment which can't be a good thing!

I just find it really strange that once the engine has warmed up a bit, then the noises both stop. It's really obvious during a cold start first thing in the morning, but it's also happening when I start it later in the day.
Si

Oh SP, that's why my car was popping and crackling going down hill... on a second gear trying to engine brake... :)

Cheers for that!
Hanah Kim

Yep Hanah, is is a 'characteristic' of the 1.8 K (not sure about lower capacity variants). Miltek/SP exhaust REALLY makes the most of this (sounds soooo cool!) Really loud popping and crackling, turns heads i can tell you! It is the one thing i really miss about that system - loads of fun!

Daytona system also produces them, but at a lower volume so it is less noticable.

Si,

Could be thermal expansion of the baffles inside the exhaust or the pipework welds. As they heat up they expand, thus closing any holes that shouldn't be there. Either way, time for a new exhaust. For the same money, you can get an aftermarket one, personally i would recommend the 2 i have already mentioned, but there are some others to consider...

Mike Satur Daytona/Indy (4 or 2 tailpipes, worth 5 bhp)
Miltex / SP Supersports (both high pitched, but SP variant is louder, exagerated power claims - worth just over 4bhp)
Pheonix (Nice rumble, but IMO exagerated power claims)
TT Fxtreme (if you can get one), Lovely deep rumble

All are Stainless Steel and guaranteed for life, probably the best reason to get one.

SF
Scarlet Fever

Sorry, typo!

Miltex should read Miltek

SF
Scarlet Fever

They sound tempting. Not being the mechanical type myself, how easy are these to fit or would it be best to leave these to the 'professionals'?

Ta,

Si.
Si

Si, I doubt that your problem is the exhaust.
Search the archives for EXHAUST BRACKET.
It is a well known problem and this bracket that costs around £6 from Rover will cure it.Bit of a bast--d to fit though.
Tim
H10 VVC
Tim Sanders

Si, are you sure it is coming from one tail pipe only? Tim's comment has reminded me of another potential cause, the flexi pipe.

If the noise sounds like it is coming from the middle of the underside of the engine, it is likely to be the flexible pipe that connects the catalyst to the exhaust manifold. These are known to deteriorate over time and do produce a 'farting' type noise. They are also one of the lowest points under the car and are a bit vulnerable to damage. Lastly, they are made of concentric rings with a woven mesh outer cover and there is aome differential movement between the componenets which would account for the noise dissapearing when the engine warms up.

Mike Satur does a Stainless Steel one that is guaranteed for life.

>> http://www.mikesatur.co.uk/images/downpipe1.jpg <<

SF
SF

Anyone thought about the spark plugs.... if one isn't functioning like it should be, a lower noise could be produced.

just my 2p,
Erik
Erik

This thread was discussed between 05/05/2002 and 08/05/2002

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