Automatic grille block

[vtec-e]

While sleep deprived last night, i came up with what i think is an idea worth following up on. A hinged door on the grille that when open, allows air to the radiator but when closed, completely blocks air to the rad, thereby retaining the precious heat. How do i activate it? Well, stick a small pneumatic cylinder on it and run a hose up to the vacumn line going to the brakes, but BETWEEN the non return valve and the inlet manifold. Therefore the brakes will hold their vacumn as normal. 90% of my grille is already blocked and the rest is right in front of the radiator so the resulting door will be quite small. When the engine is on, the door opens due to the vacumn pulling on the cylinder. But when i FAS, the door will (should!) close and keep that precious heat in. Sounds simple in theory but i may have missed a few things. Anyone got any ideas to make sure this works? I'm on the prowl in work for a suitable cylinder to do this and with winter on the way (well it feels like it here anyway, it's pi$$ing rain), is a timely mod!

ollie
ps, i'll post pics as i do it and probably put in the diy section

[justpassntime]

You could use a HAI vacuum actuator from an old air cleaner snorkle from the old carburetor days. A lot of the old cars that had hidden headlights had vacuum operated door motors.

[bikin' Ed]

Why do you want to make it so complicated? I like the hinged door (simple). But why not use an old manual choke cable or shifter cable from a bicycle to accuate it? No vaccuum leaks and the cables, in this application, would probably last forever.

[vtec-e]

I hear ya about the manual version. But i wanted something that would just do its job and not have me switching yet another thing when i FAS. One problem i do forsee is a seal failing in the pneumatic cylinder and then introducing a leak into the manifold. It would be probably spotted though as the engine might run off a little. Anyway, i do need to think some more about this so i make something simple and reliable.

ollie

[xbUser]

I am new in electronic area. However, isn't it better to open the grille when the fan is turning on? My logic: (too hot => turn on fan & open grille to cool down; not hot enough => close grille to warm the engine and getting better aero-dynamic)

[vtec-e]

Great minds think alike xbUser! Although i thought about that and i think it would make the system heat up very quickly but then need the fan to cool it. From reading stuff here and at cleanMPG i believe it is not good for FE having the fan coming on all the time. I think it's better to have a constant supply of air to stabilise temps. My temperature graph might end up looking like a sawtooth instead of a gradual rise and then a plateau, with maybe the odd spike when i get stuck behind a particularly slow moving truck or what have you.

Mind you, a variation of what you suggested would be good. Say you have a grille block that has a small opening. This is fine until going up a hill or are stuck behind a truck. Then the airflow is worse. So you could have the opening get bigger when the fan comes on, reducing the time the fan has to be on. Any thoughts?

ollie

[jamesqf]

Actually had an old Volvo (1960s? - looked like a '40s Ford) that had one of these. It was like a window shade that rolled up over the radiator, with a cable (really just string) to the dash.

[justpassntime]

Check the Squba car out....

Open


Closed

[metromizer]

Here's a thought:

The old air-cooled VW's use an alcohol-filled bellows as a thermostat, to open and close these 'flaps' within the fan shroud. The guys who engineered this back in the 50's really did their homework. When the bellows heats up, it gets taller by about 2 cm, opening up the air control flaps through a series of very simple lever arms. Flaps open allow cooling air to reach the heads and cylinders. While closed, the heaters still work, the oil cooler gets air, but the engine's top end is allowed to warm up. It's a ridiculously elegent design, that fails safe... if the bellows fails, the flaps stay in the open position. Replacement thermostat bellows for those engines are still available and cheap. The rest of the hardware wouldn't be of use for your project I don't think.

[NeilBlanchard]

Hi,

In other threads, I have seen references to a screen effectively "closing" when the pressure gets higher. So, if the grill was a screen, nothing would have to move at all.