Thread: Modified Guard Vent

Not just County's I think all pre 07 Defenders have the same brilliant system.

Originally Posted by isuzurover

Steve,

As an aside, how is the heater water valve controlled on a 110?

On a county (combined heater/AC unit) it is vacuum controlled, and opens up to let hot water through whenever you shut down and lose vacuum. So if doing stop-start driving, the AC is fighting the heater. I have seen people fit a manual tap to turn off the hot water in summer

There is no heater water valve on defenders with 300 TDI. Appears to me allowing water to circulate through the heater could be important at times for engine cooling, taking hot water from the back of the motor. I recall seeing reports that with head problems from overheating, it seems the first place normally affected is around No 4. Probably in hot weather when heater not needed and it heater core may be getting a bit blocked, best to just put a short hose from outlet fitting in the head back onto return pipe. Possibly bad for motor blocking this off or putting tap in heater water circuit. Mine has bypass at present with heater out while looking at possibility of getting better core that can be adapted to fit. (Including made of copper and brass rather than aluminium core with plastic ends)

Should also help water circulation doing what I have. Bored out heater water outlet on head, tapped half inch BSP thread into it and screwed in fitting that takes 3/4 hose - same as on other heater connections instead of standard fitting with 3/8 BSP thread that 5/8 hose fits over that creates need for stupid specially made hose with different sizes on ends.

Originally Posted by mox

There is no heater water valve on defenders with 300 TDI. Appears to me allowing water to circulate through the heater could be important at times for engine cooling, taking hot water from the back of the motor. I recall seeing reports that with head problems from overheating, it seems the first place normally affected is around No 4. Probably in hot weather when heater not needed and it heater core may be getting a bit blocked, best to just put a short hose from outlet fitting in the head back onto return pipe. Possibly bad for motor blocking this off or putting tap in heater water circuit. Mine has bypass at present with heater out while looking at possibility of getting better core that can be adapted to fit. (Including made of copper and brass rather than aluminium core with plastic ends)

Should also help water circulation doing what I have. Bored out heater water outlet on head, tapped half inch BSP thread into it and screwed in fitting that takes 3/4 hose - same as on other heater connections instead of standard fitting with 3/8 BSP thread that 5/8 hose fits over that creates need for stupid specially made hose with different sizes on ends.

You could always put in a 3-way valve to circulate the water (but not through the heater) when the heater is not in use.

Originally Posted by isuzurover

You could always put in a 3-way valve to circulate the water (but not through the heater) when the heater is not in use.

Hi All

I have considered the three way tap idea myself, does anyone know of a suitable Holden or Falcon type that could be adapted?

It would not be hard to hook up as suggested to the existing control cable as well as having a separate control for a flap for the outside air intake ( good idea roverrescue ).

Now, as I have the opposite problem to roverrescue, that is trying to keep warm on very cold frosty nights, are there any improvements for the heater, that I try ?

I do like the heater and airconditioning setup in our S1 Discovery.

Cheers Arthur

Originally Posted by wrinklearthur

Now, as I have the opposite problem to roverrescue, that is trying to keep warm on very cold frosty nights, are there any improvements for the heater, that I try ?

1. You could switch to a copper core (as mox mentioned above). Copper is more efficient than Al.

2. You could modify the heater intake so that it gets pre-warmed air - e.g. use suitably (temp) rated ducting, and run it past the exhaust/manifold/turbo first.

My TD5 factory heater appears to have a flap that cuts off ALL airflow when the fan switch is in the 0 position. I know because the cable that controls it broke, now I can have the fan on and NO air comes out, if I manually open the FLAP at the heater box then I get air. I think the issue is that that air control flap was not adjusted correctly so never really shut. Now the damned thing shuts, but it's winter and I want the heater.

Hand Throttle:

On the RHS of your steering column there's a rubber bung. Under that there is a metal bracket for a choke cable for older petrol models. This is an ideal place to fit a RRC choke cable that has a twist to lock into position function and run it to the fuel pump as a hand throttle.

I've bought the cable, but haven't got around to doing it yet, but this would be a much simpler throttle set up.

Originally Posted by KarlB

I presume you are trying to get more air into your heating/cooling duct by 'ram air effect'. I am not trying to be a white ant, but ram air effect only works at speads greater than Mach 0.3 (ie you would need to be travelling as speeds greater than 400 kph). Your modified vent may in fact reduce the airflow making your problem worse. But maybe I have misread what you are trying to achieve.

Cheers
KarlB

Oh DEAR, tisk tisk

KarlB.....your ram air effect is a different phenomenon all together, It is about the compression of air in front of an object creating a new aero shape altering the properties....usually of a wing....of the object in question. Effectively the high pressure air in front of the object acts with the object rather than as air flow over the object and the static object has essentially changed its aero shape when factoring the compressed air.....Interesting phenomenon as it can cause a lift wing to create down force, or a control surface to act in the opposite direction to what it does bellow the critical speed.

However,

A scoop on the top of a car, or virtually anywhere can get air flow equivalent to the speed travelled if there are no restrictions between external inlet and internal outlet (ie dash vent) if there is a restriction then you can get air velocity exceeding the speed of the vehicle....Minus drag etc....

Last time my landy did mach 0.3 I wasnt really worried about fiddling with the my heater knobs

And Wally (sorry Steve) if your 130 is doing Mach .3 your tuning my pump next time your in Cairns !!

Altho I suspect the EGT is gonna be of concern.