Exhaust manifold heat shields

I'm about to refit the rebuilt engine in my Range Rover 4.6 HSE. The
Exhaust manifolds are the stainless steel tubular type, and these have
heat shields on them. They are in two parts which are fitted behind
and infront, sort of clam shell like. They're a real pig to remove if
the securing bolts have seized, as typically they will on exhaust
components. I've seriously damaged mine, and I'm contemplating not
replacing them, they cost about £200 a set. I've seen some pictures
of a late Disco without heat shields, and am wondering how important
they are on the Range Rover? Could I just leave them off? Any ideas
as why they are fitted?

Alan C

<[email protected]> wrote in message
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I'm about to refit the rebuilt engine in my Range Rover 4.6 HSE. The
Exhaust manifolds are the stainless steel tubular type, and these have
heat shields on them. They are in two parts which are fitted behind
and infront, sort of clam shell like. They're a real pig to remove if
the securing bolts have seized, as typically they will on exhaust
components. I've seriously damaged mine, and I'm contemplating not
replacing them, they cost about £200 a set. I've seen some pictures
of a late Disco without heat shields, and am wondering how important
they are on the Range Rover? Could I just leave them off? Any ideas
as why they are fitted?

Alan C

They are fitted to help retain heat within the exhaust gas as this ensures a
quicker warm-up time for the lambda probes, also they help to keep
underbonnet temps down slightly, allegedly! To be honest the difference in
lambda response is absolutely minimal, as is the underbonnet temp, so it's
not a problem to just simply do away with them.
Badger.

<[email protected]> wrote in message
news:[email protected]...
I'm about to refit the rebuilt engine in my Range Rover 4.6 HSE. The
Exhaust manifolds are the stainless steel tubular type, and these have
heat shields on them. They are in two parts which are fitted behind
and infront, sort of clam shell like. They're a real pig to remove if
the securing bolts have seized, as typically they will on exhaust
components. I've seriously damaged mine, and I'm contemplating not
replacing them, they cost about £200 a set. I've seen some pictures
of a late Disco without heat shields, and am wondering how important
they are on the Range Rover? Could I just leave them off? Any ideas
as why they are fitted?

Alan C

Probably not a good idea as Badger says its pushing the heat further down
the exhaust with the results of lowering the underbonnet temperature. I
sprung for the heat wrap for the Disco (TDi) and yes it certainly makes
life easier when working over a hot engine and a little quieter too a little
more critical on a turbo ( cooler charge) but every little helps
http://www.agriemach.com/default.php?cPath=7&sort=1a&page=2
Derek

"Derek" <[email protected]> wrote in message
news:[email protected]...
>
> <[email protected]> wrote in message
> news:[email protected]...
> I'm about to refit the rebuilt engine in my Range Rover 4.6 HSE. The
> Exhaust manifolds are the stainless steel tubular type, and these have
> heat shields on them. They are in two parts which are fitted behind
> and infront, sort of clam shell like. They're a real pig to remove if
> the securing bolts have seized, as typically they will on exhaust
> components. I've seriously damaged mine, and I'm contemplating not
> replacing them, they cost about £200 a set. I've seen some pictures
> of a late Disco without heat shields, and am wondering how important
> they are on the Range Rover? Could I just leave them off? Any ideas
> as why they are fitted?
>
> Alan C
>
> Probably not a good idea as Badger says its pushing the heat further down
> the exhaust with the results of lowering the underbonnet temperature. I
> sprung for the heat wrap for the Disco (TDi) and yes it certainly makes
> life easier when working over a hot engine and a little quieter too a
little
> more critical on a turbo ( cooler charge) but every little helps
> http://www.agriemach.com/default.php?cPath=7&sort=1a&page=2
> Derek

As I said, the difference is minimal (other than when working over a hot
engine, maybe, as Derek rightly pointed out).
Personally, I don't fit them and I've never had any probs although heat-wrap
is a cheaper and simpler alternative if you want to keep something there.
Badger.

> As I said, the difference is minimal (other than when working over a hot
> engine, maybe, as Derek rightly pointed out).
> Personally, I don't fit them and I've never had any probs although heat-wrap
> is a cheaper and simpler alternative if you want to keep something there.
> Badger.

Exhaust heat rap, now I've got some of that somewhere for the kit car,
but haven't fitted it. What do you use to stop the ends from
unravelling? I'm guesing stainless wire would be good, but where can I
get some?

Alan C

[email protected] wrote:
>
> Exhaust heat rap, now I've got some of that somewhere for the kit car,
> but haven't fitted it. What do you use to stop the ends from
> unravelling? I'm guesing stainless wire would be good, but where can I
> get some?

The local sheetmetal fabrication shop - there will be several hundred
metres of it inside their MIG. ....I'm serious - it's what I use.

--
EMB

<[email protected]> wrote in message
news:[email protected]...
>> As I said, the difference is minimal (other than when working over a hot
>> engine, maybe, as Derek rightly pointed out).
>> Personally, I don't fit them and I've never had any probs although
>> heat-wrap
>> is a cheaper and simpler alternative if you want to keep something there.
>> Badger.
>
> Exhaust heat rap, now I've got some of that somewhere for the kit car,
> but haven't fitted it. What do you use to stop the ends from
> unravelling? I'm guesing stainless wire would be good, but where can I
> get some?
>
> Alan C

Either that or hose clips if you search on the Agriemach site they have the
long clips as well or there are a few suppliers on Flea bay who don't sting
for postage . if you fold the ends over before clamping they shouldn't fray.
Derek