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MG MGB GT V8 Factory Originals Technical - Can't remove exhaust

Hi

I want to remove the exhaust system so that I can get the sump off. (My 3.5 Rover)

I've undone the clamps at the bottom of the headers and removed the mountings (to allow me to give it a good 'wiggle' to loosen it) but it's not playing. I've hammered it and levered it with a tyre iron but I'm a bit worried about breaking the headers if I'm too rough.

Any suggestions as to how to get it apart? It's not likely to be rusted together as it's stainless and it can't be _that_ old as it still has the _paper_ manufacturer's lables on it.

Thanks,

Nick

Nick Wilson

Nick, sorry no idea how to get it off but having done this recently I feel your pain. What a thankless task. Remember that those sump bolts take almost no torque ... don't wanna strip 'em.
Harry

Have you got tubular headers or the cast iron ones?

If tubular then the best way is to remove the headers from the head and loosen the clamps so that you can wriggle the headers off the down pipes. Then wriggle the downpipes out of the "Y" piece.
Chris Betson

Chris,

They are tubular. I really wanted to avoid taking the headers off as there are so many stories of stripping the threads in the heads.

Though, I suppose if that's the way to do it, I'll do it.

Thanks


Nick
Nick Wilson

Sad to say I'm an expert at this having had many problems with the manifolds and down-pipes. As an alternative to Chris's suggestion (which I tried to do yesterday and gave up) I slacken the back clamp right off the pipe but leave it supported. Instead of the plain U-strap in the middle I have a tongue on the strap that I clamp to the pipe with a U-clamp so I slacken that as well. That allows me to twist the section under the floor back and fore and work the Y-piece off the two down-pipes. Then it is a simple matter to remove the down-pipes off the manifolds.

I would advise against removing the manifolds off the heads, particularly if tubular. As well as requiring new gaskets I have found with two sets of tubulars that they seem to 'shrink'. Although all the bolts went in fine when they were new, after only a relatively small number of miles I find I cannot get all the bolts back in (and they were tight to remove) because the holes no longer line up. Yesterday I had to overdrill the holes in order to get all the bolts back in.

On reassembly make sure the down-pipes are pushed well up the manifolds, then assemble the Y-piece to the down-pipes, twisting the main pipe back and fore to work it onto the down-pipes again as far as it will go, and clamp them. Then tighten the manifold clamps - pull them up really well, the PO said they had slipped off once for him, and twice I have only just caught them in time (every now and again I squint under the front to see where they are in relation to everything else). You need really good clamps here, with clean, coarse-threaded bolts and nuts. Then reclamp the middle and rear.

Good luck!
PaulH.
Paul Hunt

Hi Nick,

I've had this problem too. The way I got aound it was to remove the entire exhaust system from the Y-piece backwards. With that out of the way I was able to get each of the two pipes between the Y piece and headers off. This seems to be the way with a V8, if you want to work on component A then you need to remove components B, C, D and E first just to get at it.

Best regards

Philip
Philip Shingler

Just use a torch to heat the down pipes (but be careful of any fuel lines), this increases their diameter slightly and the Y-pipe can then be slipped out very easily.
Michael S. Domanowski

On mine the down-pipes fit *inside* the Y-piece, outside the manifolds.
Paul Hunt

I can see your problem as there is very little room. If you have the car up high enough you might be able to rig up something which give the same effect as slide hammer-I have used a large G cramp hooked around the pipe which then gave me some thing to thump downwards with a hide or better still a lead mallet.
I have found that one way to get around the down pipe clamp issue is to not clamp the pipes at all-just use a thin smear of exhaust paste.The weight of the exhaust system is taken on a large steel flat bolted across the bottom of the Range rover sump that I currently using.This supports the two pipes running back to the Y piece and means that the system does not hang from the manifolds.It also makes it a lot easier to take off.
It hasn't prevented the drivers side manifold cracking though at the collector(not helped by wrapping the primaries I suppose.Like Paul-when I went to remove the manifold I found that the manifold had changed it's length by over half a bolt hole -inspite of my having filed the holes oval to allow for expansion etc during initial installation.
If any body has found some thing that works it would be nice to know as I hate having to keep removing the steering rack....... One solution might be to change to the RV8 style manifolds-perhaps the longer primaries allow for more flexing and stress release. I also notice that the factory RV8 manifolds also have flanges interconnected to cut down the movement. Any one out there with these manifolds noticed the difference?

Regards

John Bourke

Jonh Bourke

Continually cracking manifolds was why I replaced mine.

On a slightly different topic I noticed that when I had the left-bank off the head ports had very different colours. The 1st and 5th cylinders were sort-of mid-black (unleaded), the 3rd cream-coloured as if it was very weak, and the 7th very black and sooty as if it was very rich. Comments?

PaulH.
Paul Hunt

This thread was discussed between 08/03/2001 and 12/03/2001

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