Engine cooling flaps and thermostat, Do you need them? Options

[chris914]

Do you need to have the cooling flaps and thermostat?

Will the engine run cooler with out them?

[euro911]

Good question ... I'd like to know too

also, what to do with the lower outlets if one decides to eliminate the heat exchanger tin or run something like Tangerine headers (IMG:style_emoticons/default/unsure.gif)

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[toon1]

If you are talking about the cooling flaps on the fan shroud YES you need them.

the bigger flap on the pass side if the motor directs air over the oil cooler.

There are also two flaps on the lower side of the shroud for the heaters, you need them too.

the bellows/ themostat is noce to have but not completely necassary, it's ususally broken

[jd74914]

Technically you could remove the thermostat and wedge the flaps in the position that they attain when the engine is warmed up. I wouldn't do that since it will take the engine longer to heat up to operating temperature, but if you could do it.

[chris914]

Technically you could remove the thermostat and wedge the flaps in the position that they attain when the engine is warmed up. I wouldn't do that since it will take the engine longer to heat up to operating temperature, but if you could do it.

What are other people doing with the stock tins to get the most cooling?

[Hammy]

You can go without the thermostat but you definitely need the cooling flaps.

[euro911]

I cut away my H/E tins because they were crappy anyway AND I installed an electric heater in the passenger compartment. Getting rid of the tins made doing valve adjustments a lot nicer too.

I capped off the lower outlets with rubberized tube caps and hose-clamps, however, someone told me that I should leave them open ... if they were capped off, it would cause the air flow to stall or cavitate, causing the engine to run hotter ... (IMG:style_emoticons/default/unsure.gif)

On another note, I just noticed that the cable from the thermostat bellows is broken on my wife's car. Is this a big deal (we live in So Cal)

... do I need to 'fix' the flaps in any certain position if the cable can't be reconnected (or if I remove the thermostat completely?) (IMG:style_emoticons/default/confused24.gif)

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[Hammy]

... do I need to 'fix' the flaps in any certain position if the cable can't be reconnected (or if I remove the thermostat completely?) (IMG:style_emoticons/default/confused24.gif)

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The flaps should flip open to the full cooling "fail safe" position when the thermo cable breaks or is missing.

[Bleyseng]

Technically you could remove the thermostat and wedge the flaps in the position that they attain when the engine is warmed up. I wouldn't do that since it will take the engine longer to heat up to operating temperature, but if you could do it.

What are other people doing with the stock tins to get the most cooling?

Using the all the stock tin cools it the best! (IMG:style_emoticons/default/w00t.gif)

[euro911]

Understood on the upper flaps & thermostat ... I will eventually get around to repairing the cable on my wife's car ('71 1.7)

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When I removed the stock exhaust system on my car ('75 2.0) and cut the H/E tin off of them, I noticed that the small lower flaps (into the H/E's) were missing.

SO ...

If one decides to completely eliminate the heat exchanger tin or if running after-market headers, should they:

1. Cap the lower outlets ?
2. Leave them open ?

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Another issue:

I got a phone call last night and the cooling subject brought up this interesting tid-bit:

... using slightly-modified late-model type-1 lower cooling tin plates for more uniform air flow around the cylinders (the ones that have rectangular cutouts in the bottom) ... anyone else doing this on T-4's?

I happen to have a set of them laying in the garage somewhere and will use them if they do actually provide better cooling properties.

[euro911]

Hey, this site acting up a bit ! (IMG:style_emoticons/default/WTF.gif)

[euro911]

(Multiple post of the same message) (IMG:style_emoticons/default/shades.gif)

There's no delet post button either (IMG:style_emoticons/default/dry.gif)

[joeav8tor]

I have a 73 2.0 with stock fuel injection, the thermostat works...the way it is designed the flapper over the oil cooler is open when the engine is cool and the flapper on the other side is closed (they are opposite of each other) as the engine warms up the thermostat expands allowing the cable to close the flapper over the oil cooler (routing the air through the cooler) while allowing the flapper on the other side to open...I dont know how necessary the thermostat is, and whether the flappers need to be open at any point, but I know that the air passing through the oil cooler is a good thing, and if the german engineers designed it to work in a particular way, I would rather the thermostat and flappers work, than not.
just learned that by taking the tin off and heating up the thermostat...watching what happens.
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Joe

[AvalonFal]

Anyone have a pic of what the flaps should look like? Or is there a pic in a book or maual showing it?

[Rand]

There's a spring on the bar between the flaps... If the thermostat fails or the cable breaks, the flaps snap into full-cooling position by default. No need to wedge anything into place. But maybe rotate them and let go to be sure they snap back into position.

Running without the thermostat only affects warm-up time. Not a big deal to run without. But certainly don't remove the flaps!! It will affect the oil cooler in a bad way. And don't modify the tin unless you REALLY know what you're doing. Almost all backyard cooling mods cause adverse results. The factory setup is adequate.

There are some old threads around here on this. One I recall that had pics and full explanations about how all this works. Maybe someone will use the search function and post some links.

[chris914]

http://www.914world.com/bbs2/index.php?sho...=flaps++cooling
http://www.914world.com/bbs2/index.php?act...f=5&t=30107

[McMark]

Type 1 lower tins are not useable. The stock T4 tin already has an under cylinder tins.

[Dave_Darling]

Supposedly, modified Type I under-cylinder tin is best when used with an upright cooling conversion (a la Type I cooling). The stock Type IV tins are best when used with stock type "pancake" cooling.

Or at least, that's what I have read over on the shoptalkforums BBS.

--DD

[euro911]

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Thanks Dave ... I'll use the T-4's then
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[Joe Ricard]

Best thing to do with the stock cooling system is to make sure it all works. and is optimized.
like having the tins seal off tight. the flapper tins in the fan housing operate through the full range of motion.