23 replies to this topic

[Bigfoot]

1999 Rover Mini MPi

Hey everybody,

I spent today putting my exhaust system back together, I'd dismantled it to sort a snapped manifold/downpipe stud. Everything seemed to go reasonably smoothly, I used new gaskets for the manifold/block, manifold/downpipe and downpipe/cat joints and new studs/nuts for the manifold/downpipe connection.

As far as I can tell I put it all back together as it should be (also installed a K&N filter element) but when I started it up it sounded like two tractors sumo wrestling under the bonnet.

It's running incredibly rough, the usual tailpipe blast is more of a feeble gusty splutter, and I think there was exhaust gas leaking from somewhere around the manifold (looked like it was coming up between the manifold and the heat shield). Didn't have time to investigate as I had to leg it for work.

Can anyone suggest what I may have done wrong? I'd rather it was something stupid and obvious than something complex and expensive Really don't fancy going out tomorrow and dismantling it all again.

In short - my exhaust sounds strangled and choked - what on earth's the matter?

Thankyou!
Roy

[mars red mike]

A t guess id say either the manifold isnt tight enuff against the head or its a bit mis-aligned.

[nicksuth]

Did you fit the 2 x location rings back in the inlet manifold/head recess? Re-connected ALL sensors (in particular, the Lambda Probe)?

[Bigfoot]

Yup and yup - I can try reattaching the manifold, although it's located by the two end studs, and I tightened it up as much as possible.

Rings are in, and there's no loose connectors flying around, but I'll try disconnecting them all and cleaning them up a bit, in case some dirt got trapped and messed up a connection.

[MRA]

And did you put any exhaust paste on any of these gaskets ? as with any vehicle that has a CAT exhaust paste will block it up

If its cool, start it up and see if you can feel any escaping gases, br careful though

Regards Martin

[Bigfoot]

Nope, no paste at all (I don't have any )

[MRA]

Is the head and manifold standard ? and did you use a standard gasket ?

Did it make the "tractor" noise from start up..... or was it ok then gradually started to make the noise ?

Regards Martin

[Bigfoot]

Engine is completely standard, and I used this gasket..

As soon as the engine started, it was up at 2000rpm and sounding like death on a stick, it then drops slowly to about 1000rpm while still sounding strangled. Then I switched it off as it sounded like it might stall.

[Bigfoot]

Aha! Just picking over what might have gone wrong - I put the metal side of the gasket towards the cylinder head. Am I right in thinking this is wrong (heh) and could this contribute to the problem?

Cheers.

edit: Definitely wrong (checked the old gasket), so I'll sort that, but why would that make it run so terrible?

Edited by Bigfoot, 13 May 2009 - 09:21 AM.

[nicksuth]

Aha! Just picking over what might have gone wrong - I put the metal side of the gasket towards the cylinder head. Am I right in thinking this is wrong (heh) and could this contribute to the problem?

Cheers.

Oooops, yes, the metal side goes against the manifold (usually stamped on the gasket "Manifold Side"). I'm afraid your going to have to replace it with a new one as it's probably been damaged (compressed) when you tightened it up?

[Bigfoot]

Oooops, yes, the metal side goes against the manifold (usually stamped on the gasket "Manifold Side"). I'm afraid your going to have to replace it with a new one as it's probably been damaged (compressed) when you tightened it up?

Shoot shoot shoot - will it definitely need replaced, or would I get away with reusing it? Going to be tricky getting a new one at short notice (ie today).
Thanks.

[nicksuth]

You could risk it as it's not been on very long and probably not seen too much heat? I've just compared one I took off recently with a new one and while the faces don't look to bad, it's deffinately been compressed (head side) compared to the new one. Give it a go for now and get another one on order!!

Edited by nicksuth, 13 May 2009 - 09:30 AM.

[Bigfoot]

That plan is better than no plan! Just phoning round a load of motor factors first to check.
Cheers

[MRA]

Firstly is it definately leaking at the manifold ?

Regards Martin

[Bigfoot]

Just away to go investigate further (I've sourced a new gasket, picking it up this afternoon), but when I started it yesterday, I could see some sort of gas/smoke/vapour coming from the manifold area.

I have no idea if it's simply a backwards gasket causing the problem, but I'm going to go change the gasket, clean up all the wiring connectors, put it all bac ktogether again and see what happens when I turn the key.

Best-case scenario: it was the gasket, and everything purrs away happily
Worst-case: it wasn't, and I've damaged something vital

Either way, best way of finding out is to sort it.