Modified Guard Vent

[roverrescue]

Had some time in the shed this weekend so decided to do something about an issue I have and have heard others on AULRO complain about.

Heater lever set to "cold' & blower fan 'off' - driving along with hot air coming into the cab. Our 130 runs no A/C so it is particularly noticeable when doing long runs. It is amazing to feel how much air flow runs up the glass, hot air flow at that!

Sooo, some Al offcuts, and old MIG liner, some 1.0mm hard drawn 316 wire a few screws and some tinkering resulted in this modified vent.

Push / pull cable runs inline with factory heater box control. So when cabin lever is pushed to hot, flap on guard opens. Slide control to cold and flap closes. Havent tested it on a long run yet but no air leaking so far with flap closed. Overall should help to keep cabin temps down a bit on longer runs.

Next stage this arvo is I plan on converting the windscreen/footwell controller to be a hand throttle. We only ever run the heater onto the glass (and very rarely at that) and using the existing controller will be a very neat setup.

Photos give an idea of the vent.

Steve

[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

[isuzurover]

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.

Cheers
KarlB

No - the opposite - I read that he is trying to shut off airflow when on the cold setting.

Btw - any fluid dynamics calcs to back up your assertion?

[Landy110]

Clearly Karl, clearly you didn't read the post, no he is not after a ram air effect. Quite the opposite, he is after a NO air effect.
As such, his mod is quite good.

Steve

[roverrescue]

Karl,
As mentioned above, the mods purpose is to prevent air into the heater box and this works very well.

But despite your assertion that when open less air will enter when open at sub Mach 0.3 I beg to differ!
At 80kph (a touch less than M0.3) with the vent open and blower off feels equivalent to blower fan setting 1 whilst stationary. Soooo either my defender bends the space time continuum to achieve mach 0.3 or/ the speedo is a touch out and my flogged out 300tdi is punching above its weight!

Being the shallow person that I am, any landy experiements I try and fail on will never get posted up here! There are quite a few of them ;)

Steve

[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 :D

[KarlB]

No - the opposite - I read that he is trying to shut off airflow when on the cold setting.

Btw - any fluid dynamics calcs to back up your assertion?

Eek! No! I gave up physics as soon as a I could. And fluid dynamics is almost a black art (like metalurgy). However, a good starting point might be http://www.paladinmicro.com/documents/RamAirMyth.pdf. Alternatively just Google "ram air effect".

Cheers
KarlB

[KarlB]

Yes, I didn't read properly but that is not unusual for me! So, as I read it a second time, the issue is that with the the air vent 'normally close', air still comes in so blocking the entrance solves this. Then a very neat solution.

Cheers
KarlB

[isuzurover]

Eek! No! I gave up physics as soon as a I could. And fluid dynamics is almost a black art (like metalurgy). However, a good starting point might be http://www.paladinmicro.com/documents/RamAirMyth.pdf. Alternatively just Google "ram air effect".

Cheers
KarlB

He is arguing something slightly different - and his logic is flawed - I note a lack of maths in his rant.

Like most things, fluid mechanics is a continuum, rather than discrete in nature. You can get changes in pressure and/or flow rate without compressing air.

If his argument were true, bonnet scoops over intercoolers would have no airflow unless there was a fan underneath or you were travelling at mach 0.3 or above.

[roverrescue]

Ben,
On a 300tdi there is no tap in the heater circuit. Full flow from thermo housing through the heater matrix and back into the head.
A tap was another option I had contemplated however I wondered if doing that to a 300 designed with full flow may create some other head cooling issue. Probably not considering people block the heaters off in discos with dead heater matrixes?

Besides doing it this way gets rid of the poxy plastic cover piece. But it will be interesting to see how the blower motor holds up in the wet (when I actually use the heater to defog the glass) time will tell.

S

[JDNSW]

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 :D

The 110 including non-air Countys such as mine do not have a water control valve at all. They have a shutter that diverts airflow either around or through the heater core.

This clever design allows the heating/cooling system to deliver slightly warmed air in cold weather when set to hot, and preheated air in hot weather when set to cold (possibly something to do with the proximity of the heater to the exhaust manifold). Also, the "off" airflow position does not completely stop airflow, this being very noticeable in hot weather. (As noted by Steve)
John

[VladTepes]

Not just County's I think all pre 07 Defenders have the same brilliant :lol2: system.

[mox]

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 :D

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.

[isuzurover]

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.

[wrinklearthur]

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 ). :BigThumb:

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

[isuzurover]

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.

[BilboBoggles]

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.

[Michael2]

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.

[popemobile]

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.

[roverrescue]

"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."

Miscellaneous plastic crap like the steering column covers have been long ago removed from me fender. If you have a play with the windscreen - footwell lever you will see it has hand throttle written all over it. Just need to re-stock on the 49 strand mackie wire to join the hard wire to then she will be bananas!

S

[Bush65]

All Land Rovers and Range Rovers that I have owned, have had continuous coolant water flow through to heater core. This is a cheap method to alow some water circulation in the coolant passages of block and head until the thermostat opens.

Don't use a valve to block the flow to the heater unless you use 3-way valves to create a bypass circuit.

With an Isuzu engine,the one I have from a truck has a bypass system at the water pump. I don't know if the 4BD1 factory fitted to Land Rovers has the same bypass on the water pump.

[wrinklearthur]

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

So what did you drive off the top of, to achieve that speed?

More importantly, was the heater effective at that speed, or did the function reverse and blow cold air, as per the ram effect?

Cheers Arthur

[Brad110]

Where will you connect the hand throttle cable to?
The Army defender have hand throttle cable (Pull on and turn lock}
on the R/H position for a choke cable (normal ignition on every other car)
You could use a choke cable- I had an old 40 series Tojo which had a hand throttle of tis designand it worked well.

Again where in the controls would you connect the cable? I have a short cable and control which I have wanted to fit for some time.

Regards

[roverrescue]

pull the two sliders on the right side of the dash.
The inner one is for the heater flap
The outer one drives a push pull wire to shange between windscreen and footwell vents.
Simple matter of locking your push pull wire to the mechanism.
Pass push pull wire alongside factory throttle cable.
Firmly attach both outer sheat
Connect some soft pliable wire (like 49 strand) to the push pull wire and attach the soft wire to the U-Clip on the top of the injector pump.

When you now slide the lever, cable will pull on soft wire. Spring return on IP will keep everything under tension.

Ill take some photos when its done - still waiting on 49 strand.

S