Missing Pipe - V8 Inlet Manifold

[Skibum346]

As some of you may remember I recently replaced the head gaskets on my beastie. Now when I put it back together, I noticed a banjo bolt on the back half of the inlet manifold (Shown as item 11 on the pic below). At the time I couldn't find a pipe to go onto it that I'd taken off so left it.



However, the more I think about it, the more it concerns me. Surely our favourite manufacture wouldn't have put it there if it didn't have a purpose?

So... the questions...

1. What is it?
2. What should it be connected to?

Thanks in advance for your help!

Skibum

[Range Rover Blues]

There are a few things that run from the engine vacuum, some more important than others.

The vac adavnce will be from the carb, so no worries there.

Brake vacuum servo

Heater air recirculate on some models

Fully cold heater valve on some models

carbon air scrubber on EFi models

hot/cold engine air inlet on some carb models

[Skibum346]

Hmmmm.... think I'll have to visit my local specialist top narrow your list down some RRB... but thanks!

Skibum

[Range Rover Blues]

I had a thought, crankcase oil breather.

[Range Rover Blues]

Ok, I had a look at the Haynes manual and I think it's the vacuum supply to the thermostatic control of air temperature for the carbs.  It's not the crank vent as this goes into the carbs (yuk), I can't see where the servo connects but that would be bigger IMHO.

So, do you have original air filters or after market bath sponges?  the original ones would have had a small bore black pipe that goes from a diaphram on the end of each trumpet via a thermostatic valve inside the airboxs, to a 'T' and back to that elbow you have found.

[Skibum346]

Ok, I had a look at the Haynes manual and I think it's the vacuum supply to the thermostatic control of air temperature for the carbs.  It's not the crank vent as this goes into the carbs (yuk), I can't see where the servo connects but that would be bigger IMHO.

So, do you have original air filters or after market bath sponges?  the original ones would have had a small bore black pipe that goes from a diaphram on the end of each trumpet via a thermostatic valve inside the airboxs, to a 'T' and back to that elbow you have found.

Remember this is a 3.5 carbed engine so airbox sits behind the carbs, Air in comes between the carbs to the air box, from the airbox, a U-shaped cast pipe connects to the carb air intake.

Don't recognise your description above about "diaphragm at end of trumpet"...  :-k

[Range Rover Blues]

Ok, you have the oval air box, good.  There should be a pipe that runs from the airbox between the carbs, it's metal and part of the aribox.  At the end of it is there a round lump sat on top? inside it there is a diaphram which controls a flap to direct air either from a hot place or a cold place, usually an exhast manifold but I couldn't see it in the manual.

Well if you find the diaphram then the pipe should go back to one end of the airbox where the thermostat is and from there to the elbow.

[Skibum346]

Ok, you have the oval air box, good.  There should be a pipe that runs from the airbox between the carbs, it's metal and part of the aribox.  At the end of it is there a round lump sat on top? inside it there is a diaphram which controls a flap to direct air either from a hot place or a cold place, usually an exhast manifold but I couldn't see it in the manual.

Well if you find the diaphram then the pipe should go back to one end of the airbox where the thermostat is and from there to the elbow.

Ahhh... that'll be the ipe that's folded back on itself and clamped with a small jubilee clip then!  :roll: 8-[

I'll check out the airbox diagrams and see what I can find as I'm never too good with word pictures!

Thanks RRB.... as ever you've got me on the right road!   :tappity:

Skibum

[Range Rover Blues]

Of course a lazy man would just shove a screw into a bit of old washer jet pipe and bung that on both ends, that way I think it will run on cold air all the time.