Section : Exhaust

Help, is my manifold scrap?

Posted By : Paul Hewitson, 26-Mar-2007, 08:58pm

Hi,

Have just been trying to fix a blowing exhaust/manifold join on my Mk3 Spit and have made a rather unhappy discovery. I think that at least some of my problems can be attributed to a completely stripped stud (only came to light after several minutes of wondering why the nut wouldn't tighten up).

What I want to know (as the title of the thread gives a hint to) is
- is it possible to remove the offending stud?
- is a hard task to remove/will it require specialist equipment? or
- is the whole manifold just for the scrap heap?

Any advice gratefully recieved.

Cheers

Paul H

Followups :

Help, is my manifold scrap?

Posted By : Calvin Andrew, 26-Mar-2007, 09:11pm

Here goes Paul,
I imagine it can be drilled out carefully and a new one inserted,
but, i imagine that as so many people have switched to extractor stainless manifolds, there would be a fair supply of cheap secondhanders around, maybe someone on the forum might have one.(Unless they all had the same problem as you that is)
Have seen the bodge too where the stud is drilled out and then a bolt put through and a nut on the end, but even my reputation for rough bodges would not take me there,
good luck mate,
Calvin
- Help, is my manifold scrap?
  
  Posted By : Sam Hayes, 26-Mar-2007, 09:25pm
  
  I had a similar problem with a stud on my car's original manifold, which meant it was blowing incessantly, but in the end I just bought another one very cheaply which has all three studs drilled out through the bodge described above, and it actually works ok - a good dollop of gun gum on the join, and some good quality bolts. I'd recommend having the downpipe anchored to the bellhousing (as it should be, I believe, although someone disconnected mine somewhere along the line!), as it keeps the whole thing a bit more still. Some experimentation with nuts, bolts and washers was needed, though, but it's a cheap fix that's got it through a couple of MOTs so far, although it's not very pretty and I'll definitely replace it with a tubular one, one of these days.
  
  Sam
  - Help, is my manifold scrap?
    
    Posted By : Paul Hewitson, 26-Mar-2007, 09:39pm
    
    Thanks for the pointers guys,
    
    can you give me a clue as to how difficult the manifold is to get off the engine.
    
    Cheers
    
    P
    - Help, is my manifold scrap?
      
      Posted By : Calvin Andrew, 26-Mar-2007, 10:12pm
      
      relatively easy Paul, but lots of WD40, patience and grazed knuckles, these are nuts on studs in the head, so be careful on retightening,
      cheers Calvin,
      ps, i am not the expert here and i expect someopne will add or correct me if i am wrong, but that is how it happened for me,
      i would invest in a new exhaust/inlet manifold gasket too, goes between manifolds and head and will probably get damaged in the removal process.
      - Help, is my manifold scrap?
        
        Posted By : Philip Brammer, 27-Mar-2007, 00:08am
        
        If you have the manifold off I would also suggest heating the stud area with a blowtorch as hot as you can as you try to remove the studs. If you get it right you will get burned as well as skinned knuckles! A badge of honour to be respected! As I say the only long term solution is an extractor manifold, well worth the money.
        
        Help, is my manifold scrap?
        
        Posted By : Sam Hayes, 27-Mar-2007, 01:59am
        
        The other thing to remember is that there could be two 'hot spot' bolts that link the exhaust and inlet manifolds. I spent some time tugging at the exhaust manifold having removed the head studs only to find I hadn't discovered and undone these (perhaps I should have had the manual open at the time...). However, some months later, after I'd left the car with a garage for a while to sort a few engine things out, they mysteriously disappeared, so yours could have done too...!
- Help, is my manifold scrap?
  
  Posted By : Chris Taylor, 27-Mar-2007, 03:14pm
  
  Having done the bodge of drilling out and fitting a bolt myself, I would actually recommend it!! (Well, I would say that wouldn't I?)
  It has the advantage that it does not require the same degree of accuracy in drilling, and you will never have the same problem again! If you drill the hole in the manifold flange a little larger than strictly necessary, you can have a little play to help align an exhaust downpipe that may be slightly misaligned, poorly made etc.
  It does mean you need two spanners to tighten up each nut at the join, but there should be enough space to get a spanner on the bolt head.
  If you want the joint exactly as original, the easiest way to do this would be to buy a secondhand manifold. If you need to drill out the worn/broken stud, you can try tapping the flange for a new stud if you have the necessary tools and skill to do the job. If not, you can make a satisfactory repair by drilling right through and inserting a bolt through the flange.