Exhaust manifolds leaking around collector

[DickyP]

Hi all,

This is my first starter post, so please go gently :-> I've had my Chimaera for a few months and gradually working through all the jobs that need doing, and many thanks for all the information here - it's been a huge help.
I'm trying to resolve a leak on the manifolds, which is manifesting itself in the well documented tapping noise. I've identified one of the gaskets at the head was leaking, so can resolve that. However, while the manifolds were off I thought it made sense to check for the also well documented collector leak, so filled them with water, only to find them leaking there also! I've taken them to a local exhaust specialist who opened them up at the cat, and re-welded them from the inside. They did comment on how one hadn't been finished properly originally, and this coincided with the one that was leaking the most. Upon getting them home I tested them again with water out of diligence, only to find them still leaking (now worse). I can see the exhaust place did do the work, and they showed me photographs when I collected (they're also well respected so I'm not doubting them). I've been back and they've advised there must be a problem at the pipework that cannot be seen (i.e. where all 4 are together heading towards the collector), so the only solution will be to make up new manifolds which will be very expensive.
I thought I'd post my experience and ask for advise. I've searched and couldn't find any other reports of this. In the meantime I've put some Gungum down the holes between the pipes to the collector and waiting for that to set to see if that resolves the issue as a temporary measure.

Cheers in advance
Rich

[QBee]

DickyP said:

Hi all,

This is my first starter post, so please go gently :-> I've had my Chimaera for a few months and gradually working through all the jobs that need doing, and many thanks for all the information here - it's been a huge help.
I'm trying to resolve a leak on the manifolds, which is manifesting itself in the well documented tapping noise. I've identified one of the gaskets at the head was leaking, so can resolve that. However, while the manifolds were off I thought it made sense to check for the also well documented collector leak, so filled them with water, only to find them leaking there also! I've taken them to a local exhaust specialist who opened them up at the cat, and re-welded them from the inside. They did comment on how one hadn't been finished properly originally, and this coincided with the one that was leaking the most. Upon getting them home I tested them again with water out of diligence, only to find them still leaking (now worse). I can see the exhaust place did do the work, and they showed me photographs when I collected (they're also well respected so I'm not doubting them). I've been back and they've advised there must be a problem at the pipework that cannot be seen (i.e. where all 4 are together heading towards the collector), so the only solution will be to make up new manifolds which will be very expensive.
I thought I'd post my experience and ask for advise. I've searched and couldn't find any other reports of this. In the meantime I've put some Gungum down the holes between the pipes to the collector and waiting for that to set to see if that resolves the issue as a temporary measure.

Cheers in advance
Rich

1. Keep an eye on Classifieds or the Bay of Fleas - you can sometimes pick up a spare set.
2. I may have one spare with a cat in it - I bought a pair of de-catted manifolds when i went de-catted, only to find that one was about an inch and a half shorter than the other! So I had to decat one of mine after all, but I think I may still have the other one. If you want it I can see if i still have it tomorrow (at work today). It has a pre-cat in it, and has previously had the 4>1 fault welded up.

Edited to add - Erin Doors has just been to check and I do still have it - driver's side if she has described it correctly.

Edited by QBee on Wednesday 5th February 15:31

[DickyP]

Hi QBee,

Thanks for the reply and advice. It's both sides that have gone (annoyingly). The passengers wasn't too bad before and only showed a damp patch under the water test, but after the welding drips like the drivers side did.
I did wonder whether to keep an eye out for a second set, but was concerned that I'd buy another with the same issue, so thought I'd post and find out what other peoples experience was before I took the plunge.....
Can I assume I've just been unlucky? My car's a 1998 by the way.

Cheers
Rich

[QBee]

I am told that it is a common fault with these cars.

I hear what you say about your exhaust guys.....but my feeling is that they have done a less than adequate job. If they have made both worse, then they are failing in their job, as they claim to be exhaust experts. Presumably they are now leaking around where they cut them open?

Mine, if you want the one, has already been cut open, welded up at the union, then welded closed again, and it was checked by my TVR guy with a listening tube prior to re-installing it. I vaguely remember it had to go back to be done again...... You live near me, and are welcome to try your water test prior to saying yea or nay.

As to buying a pair off the web, the one key question to ask is "have they had the 4>1 union welded up?" If the guy doesn't know, ask if he can see a tell tale weld around the pre-cat area?

[DickyP]

Thanks. The leak does appear to be in the same place, but it comes from within where the pipes join so I'm unable the see the exact location. I understand the work that was done was to cut them open at the cat, then to weld from the inside where the pipes come in. It doesn't look like they removed the individual pipes themselves.
A quick look at those for sale (on a popular auction site) shows no visible sign of the repairs being done, so it looks like I need to find somewhere local that knows what to do with these pipes (either my own or of I buy another pair). Any recommendations for the Nottinghamshire area?
QBee - noted you have a drivers side available! I'll need to sort the passenger though...

[BarnFind]

Do you not take the angle grinder to them to get to the bits that need welding up and then reweld the cuts up again being careful to mark them first or am i missing the point ? think that was what was done on mine.

[sapper]

exhausts are a pain when welding, I would suggest getting someone to bronze weld it. if you can get at the area where the leaks are this should fix it. avoid full fusion welding, too much carbon in the mix will make it fall apart.

[QBee]

Mine were welded in Norfolk. Can probably get them dropped off to be done for you.
Mine cost just over £100 for both to be cut open, welded up, and welded back together.
I am off to Norfolk first sparrowfart on Saturday.

[A900ss]

QBee said:

Mine were welded in Norfolk. Can probably get them dropped off to be done for you.
Mine cost just over £100 for both to be cut open, welded up, and welded back together.
I am off to Norfolk first sparrowfart on Saturday.

I'm getting this done at the moment.

Cut open, pre cats removed, non reversal cones fitted and re-welded. £100 for the pair plus labour to fit and remove.

[DickyP]

Thanks all for the advice so far. As an update, I water tested the 'Gungum'ed' manifolds and they're now watertight, so have just fitted them back on the car. It's had a momentary warm through to help the Gumgum set - not sure how successful it'll be as not sure it's going to like the heat there...
I guess it starting to look like I had a bad welding job done then!

[mach2]

A900ss said:

I'm getting this done at the moment.

Cut open, pre cats removed, non reversal cones fitted and re-welded. £100 for the pair plus labour to fit and remove.

Can I ask where you are having this done please? I fancy having the pre cats removed but don't fancy losing the skin on my knuckles!
Based in North Bristol so not too far from you.

[QBee]

Hope you have spotted the Burghley Show thread......April 13th? With a (presumably south) Lincolnshire run out on the day before. Well worth going along - should be upwards of 500 TVRs at the show. Just 35 miles down the A1.

[A900ss]

mach2 said:

Can I ask where you are having this done please? I fancy having the pre cats removed but don't fancy losing the skin on my knuckles!
Based in North Bristol so not too far from you.

YHM

[DickyP]

QBee said:

Hope you have spotted the Burghley Show thread......April 13th? With a (presumably south) Lincolnshire run out on the day before. Well worth going along - should be upwards of 500 TVRs at the show. Just 35 miles down the A1.

Yes, I'll be going to the Burghley Show. Looking forward to it!