V8 Exhaust

[Phill S]

Thanks for the tip, I'll stop by there in the morning and have a ferret. I have it suspended on a ratchet strap at the moment while I wait for a collection of bits to arrive. Will report back on how it goes...

[FridgeFreezer]

Well I just went and pointed the camera under the 127 so here's my setup...

 

The vehicle was originally a factory V8, it's now on a 4.6 with (I think) RRC/D2 cast manfiolds, the Y-piece you see is custom purely because I was in Longlife getting the mid-section made single-piece and asked them to do it with a couple of small flexis in just to take up the slight misalignment you can get that stops the manifold-to-downpipe joint sealing reliably (at least they always seem to be a pain for me).

I'm assuming the x-member is original but no idea if that's right or not.

[ped]

i think i used the rangerover twin down pipes on mine but it was a long time ago i did it
i remember i had to use the rangerover solid front prop to get clearance

[ThreePointFive]

On 5/7/2023 at 4:50 PM, FridgeFreezer said:

Well I just went and pointed the camera under the 127 so here's my setup...

 

The vehicle was originally a factory V8, it's now on a 4.6 with (I think) RRC/D2 cast manfiolds, the Y-piece you see is custom purely because I was in Longlife getting the mid-section made single-piece and asked them to do it with a couple of small flexis in just to take up the slight misalignment you can get that stops the manifold-to-downpipe joint sealing reliably (at least they always seem to be a pain for me).

I'm assuming the x-member is original but no idea if that's right or not.

Pretty much confirms that RR cast manifolds and downpipes will always want to go under/through a defender cross member. Bowlocks.

[FridgeFreezer]

15 hours ago, ThreePointFive said:

Pretty much confirms that RR cast manifolds and downpipes will always want to go under/through a defender cross member. Bowlocks.

On the plus side, unbolting & modding that crossmember is a nice easy job.

[ThreePointFive]

Not mine, it's galvanised. It's also bigger than the box section ones everyone else seems to have.

[Phill S]

On 5/2/2023 at 4:48 PM, Phill S said:

Will report back on how it goes...

Well that took longer than it was supposed to. Long story...

Here's a walk through of what I did so's you can tell me how I should have done it. First off, olive CRC4579L in place and nuts finger tight. Downpipes supported at the rear in the guesstimated correct position:

 

Here's the centre section strapped up into place with the gasket between the mid and rear sections and tightened up:

 

And the rear end sitting about right:

 

I had to make up a length of box section to get hanger ESR3294 to sit correctly:

 

Which bolts up like so:

 

Yeah, some work still to do on that...

With the front and rear points now fixed, attention turns to the front of the mid section. I chopped all the hangers off of the donor Disco exhaust, and made this:

 

Cute ain't it? Problem being that I couldn't get a decent measurement to get it to hang correctly. This way I could wind the contraption up and down until it felt right. It looks much worse in this pic than in real life:

 

That's my story and I'm sticking to it. I had to wrench the YRM 300 TdI middle hanger (designated 016B) around through about 90 deg to get it to sit about right. And just to show the lower end:

 

OK, beautiful it's not, but it'll give me a pattern to work from next time around when I'm fitting a proper exhaust system and I'll rework the hanger at that point. Probably...

That leaves the middle hanger. I made this:

 

3mm steel plate with one of the original Disco 1 hangers welded on. Yeah, I know. But it's not going to fall off.

That was much easier to measure up, and fits like so:

 

I bolted it on using the self-levelling unit fixings. Happy with that one.

So I have a set of hangers that should do the job for the foreseeable, and means that when I come to fit a stainless system I should be able to go out and buy a standard TD5 one and it'll just go on without having to think about it. Well - maybe.

On to the next outstanding problem...

[Bowie69]

That looks great

[FridgeFreezer]

Not 100% clear from the pics but the front-to-centre section mounts solidly on the transfer case bracket, so the exhaust is rigid to the engine & gearbox but flexi mounted to the chassis from there back.

[Phill S]

14 minutes ago, FridgeFreezer said:

mounts solidly on the transfer case bracket

Aah - maybe I made a problem for myself because I used non-standard brackets?

 

[Bowie69]

On an RRC/Disco the transfer box area mount is attached to the transfer box mount, with a rubber, so not hard mounted to the transfer case.

That said, there's no flexi in there at all on an RRC.

[Junglie]

You're rapidly filling my internet bookmarks. Thanks for the many and detailed bits of info...

[FridgeFreezer]

1 hour ago, Bowie69 said:

On an RRC/Disco the transfer box area mount is attached to the transfer box mount, with a rubber, so not hard mounted to the transfer case.

The exhaust mounts to the transfer box side not the chassis side so there's no flex - if you think about it, the exhaust wants to move with the engine otherwise it will pull itself apart as the drivetrain moves on its rubber mounts.

[Bowie69]

Agreed there shouldn't be, but on an RRC V8 it is rubber-hanger mounted to the transfer. I always thought it weird in a way, but perhaps it is there so they don't need a flexi section at all?

[Phill S]

My brain hurts....

[Paul C]

I think in the RR and disco the joint between the y pipe and the front muffler is a bell and mushroom arrangement with a clamp that does allow a certain amount of movement.  I seem to remember one model had springs on the clamp plate bolts. 

[Phill S]

It's been a while. So I'm going with what I've got on the exhaust for the time being, but a couple of questions.

For obvious reasons I've used brass nuts on the manifold to downpipe joints - new gaskets of course. Getting some chuffing from the joints as the thing warms up - anybody able to suggest a max torque setting for the nuts? Not sure what they'll take and wimped out of tightening up too much.

I have a pool of water dripping from the downpipes to exhaust joint. New system, Britparts finest and a new ring. I see the workshop manual says to use a sealant - any recommendations on what product to use on that? Not something I've used this century...

[mickeyw]

I've never had any luck keeping brass exhaust nuts tight, even with a locking nut behind the. These days I use stainless exhaust studs and BZP plain nuts with a spring washer.

[FridgeFreezer]

12 hours ago, mickeyw said:

I've never had any luck keeping brass exhaust nuts tight, even with a locking nut behind the. These days I use stainless exhaust studs and BZP plain nuts with a spring washer.

My manifold-to-head nuts are all brass (UNF which may help), I've had terrible trouble with the downpipe-to-manifold joints coming loose though, culminating in machining my own thicker & properly flat stainless flanges and getting Longlife to make me some D2 style downpipes with small flexi joints in to reduce any stresses / vibrations... even then, one did move 1st time pout playing - I've since sleeved the holes in the flange to remove the wiggle room around the studs, used Aerotight nuts, and fitted Nord Lock washers under the nuts and it's been OK so far.

Also replaced the gaskets with some copper-based goop recommended by Nige - V-Tech VT153 RTV. Not entirely sure it's any better than similar products from Loctite or whoever but it's working for me so I won't knock it.

[Phill S]

Well, I've used brass nuts on other vehicles before, but not the RV8...

 

7 hours ago, FridgeFreezer said:

Aerotight nuts, and fitted Nord Lock washers

That sounds like a promising combination. Might try those with the standard tin gaskets and without the goo first...

[Phill S]

So I'm having trouble getting a decent seal between the manifold and downpipe on the drivers side - RHD. Do I understand correctly from:

 

On 3/13/2024 at 9:48 AM, FridgeFreezer said:

Also replaced the gaskets with some copper-based goop recommended by Nige - V-Tech VT153 RTV

 

that you ditched the tin gaskets and used only the goo? And that works?

[FridgeFreezer]

42 minutes ago, Phill S said:

that you ditched the tin gaskets and used only the goo? And that works?

I ditched the downpipe gaskets for the goo PLUS Nord-Lok washers and so far that appears to have held, although it's only been out twice since then so a grand total of a couple of hundred miles plus 2 days off-road playing.

The 127 will be getting the same treatment soon as it's due to do maybe a 1000 mile round trip abroad so we'll see how that works out and report back.

[Phill S]

Ok thanks. I used the nuts and washers you suggested plus standard tin gasket but still have the problem. And a burned wrist from locating the problem. The goo worked fine on the downpipe to silencer box end, but then you'd expect it to I guess. Will go and anguish about what to do next....