Cooling system flaps, how are they supposed to be oriented? Options

[ChrisFoley]

If you take out the flaps, you are not forcing the air to go through the oil cooler, which will result in higher oil temps.

Do you have test results?

[SirAndy]

Without the flaps there will be no air flow to the oil-cooler.

I don't believe that for a second. (IMG:style_emoticons/default/cool_shades.gif)

Well, there will be some, but it is severely limited ... (IMG:style_emoticons/default/cool_shades.gif)

[Root_Werks]

(IMG:style_emoticons/default/rolleyes.gif) (insert big sigh here)

There is probably a reason VW spent money developing the flappers to function like they do. At worst, I'd leave them in the failed open position always working to get the thermostat fixed, hooked up or whatever.

Threads like this kinda scare me. People wanting to run their "Street" cars as cool as possible.

Cool, go for it and have fun trying to burn all that condensate out of the crankcase and oil.

(IMG:style_emoticons/default/aktion035.gif)

[McMark]

Everyone knows auto manufacturers like to spend time and money developing parts that are completely unnecessary. (IMG:style_emoticons/default/rolleyes.gif)

[VaccaRabite]

If you take out the flaps, you are not forcing the air to go through the oil cooler, which will result in higher oil temps.

Do you have test results?

Nope. And I am not willing to chance it with my engine, either.

I can say, though, that air will follow the path of least resistance. The flap over the oil cooler forces a percentage of the air going through the tins to be diverted to the oil cooler. There is no where else for it to go. Without the flap, the oil cooler would be a natural low pressure area, and would suck up a little warm air from under the tins into the cool air above the tins. It would not provide much, if any, cooling to the oil, aside from being a heat sink.

So, no. I don't have tests to prove it. But I am willing to believe in the theory until proven otherwise. I am always willing to be proven otherwise if someone is willing to run the tests in a relatively scientific manner.

Zach

[JeffBowlsby]

Fixed my photos descriptions above. These OK now? I got these photos somewhere, apparently the descriptions were wrong there too.

[Root_Werks]

I noticed this morning the engine was running "cool" on the temp gauge. Popped the lid when I got to work, yup the little cable worked loose. Gotta fix it.

Had that not happened to me this morning, I'm pretty sure I wouldn't have bothered posting to this thread. This has been hashed out so many times I've tossed my arms up in the air to it. People will do what they want anyway.

BTW - with my 914 running cooler and having carbs, it pretty much ran like poo the whole way to work. Never really warmed up to what I have things tuned to. FI will most likely compensate for the cooler running, but carbs generally don't.

[Cevan]

I noticed this morning the engine was running "cool" on the temp gauge. Popped the lid when I got to work, yup the little cable worked loose. Gotta fix it.

Had that not happened to me this morning, I'm pretty sure I wouldn't have bothered posting to this thread. This has been hashed out so many times I've tossed my arms up in the air to it. People will do what they want anyway.

BTW - with my 914 running cooler and having carbs, it pretty much ran like poo the whole way to work. Never really warmed up to what I have things tuned to. FI will most likely compensate for the cooler running, but carbs generally don't.

Assuming your cooling flaps are installed correctly with the springs in place, if the cable came loose from the pinch bolt (or if the cable broke), the flaps would spring open to the "warmed up" position. Assuming your drive to work was at least 15 minutes, the engine oil should have come up to operating tempurature by then.

I think you may have a different problem, maybe with your carbs. I have my cooling flaps installed and connected to the thermostat. My engine running dual carbs runs fine right out of the gate and continues to run great after the oil is fully warmed up.

Correct me if I'm wrong, but the heads and the combustion chamber come up to temps pretty damn quick, like in a manner of minutes. Not sure how oil temps make the engine run like poo.

[stateofidleness]

so you guys "scrapping" your cooling fins, care to donate them? (IMG:style_emoticons/default/smile.gif)

[VaccaRabite]

Correct me if I'm wrong, but the heads and the combustion chamber come up to temps pretty damn quick, like in a manner of minutes. Not sure how oil temps make the engine run like poo.

Yes and no. The heads come up to temp fast, but can also lose it fast, particularly on down hill runs, off throttle. I will regularly see my head temps drop into the 220 - 250 range, especially on my drive to work on a cooler morning. Its all fast, long downhills. Optimal temps are ~270-370.

Zach

[ME733]

...........My preferred orentation for the heater flaps is.....folded over and driven into the ground., this saves a lot of concern over whether they are orented properly, the intermediate connection is stable, the bellows is working,the wire is still attached, or the roller is broken....and it saves the weight of that worthless crap from being hauled around....The , not insiginificant , side benefit of knowing your engine will not overheat from any failures of all that junk will give you a significant level of piece of mind. You will just have to allow a few minutes to warm up the engine before driving.(recommended for any air cooled engine-including your lawn mower, or private airplane.).

Cool, so your telling me i can take the whole flap system out and call it good? Is there anything else that i will need to pay attention to, or set up different without these flaps in? It did seem like i could just leave them out, but i wasnt quite sure how the air flows through everything.

.........Detox...may have a resonable suggeston., however I toss EVERYTHING..I have found that the oil cooler cools just fine without the part he suggests....discuss this with your engine builder...ONE other thing to look for ...the plastic wheel for the bellows wire pull...has a bolt into the crankcase., you will need to install an appropiately small, bolt with sealant to seal this HOLE., when you decide to toss the flapper junk...The small openings (for the flapper ends which protrude thru the sheetmetal)...can be rubber plugged, sealed with a small bolt and nut, (prior to sheetmetal installation)...or left open-do nothing...it,s all good.

.............If you can believe the FACT that the sheetmetal is pressurised, (by the fan), any concern that the oil cooler will not work is unfounded. I have built enough of these engines without flaps and bottom cylinder deflectors to know it all works just fine-BUT all the engines were carburated, and therefore produced more h.p. than a stock engine.....it,s possable, i suppose, that a F.I. engine, in the depths of winter could run too cold. This would be true ALSO with any UPRIGHT fan engine, no matter whose type or design you might have.(because they too do not have "flappers and oil cooler diverters.)....practically speaking F.I. o.e.m. engines are limited severly in camshaft duration and lift due to the design of O.E.M. system.(In stock form). By virtue of using carburators, and a higher duration/lift camshaft--to achieve more H.P. at a higher rpm range, the engine will have more btu,s of heat which must be disapated/removed for engine durability and longetively.my suggestions are based on experience. Additionally for a historic perspective-back in the day of formula super-vee which used the type IV engine. those cars had no fan at all, just air-flow from air scoops, used fabricated fiberglass cylinder covers-no flappers, no oil cooler diverters,no bottom cylinder deflectors....and reved to 8500 rpms, producing more than 165 h.p.with carburators.(solex 40p11)...the engines were good for the entire racing season.The O.E.M. cast fan is efficient, and will cool off the engine just fine.(and provides a counterbalance for the flywheel, and P.P. at the centerline of the crankshaft.). it,s a good system and with a few minor tweeks is even better for engines with higher than stock H.P.

[ChrisFoley]

The O.E.M. cast fan is efficient, and will cool off the engine just fine.

That's true up to a point, however the inability to increase fan rpm relative to crankshaft rpm means it is impossible to increase the cooling ability of the stock system beyond merely freeing up the airflow through the system.

There is another shortcoming of the stock system. The oil cooler always sees about the same airflow even when the oil is not up to temperature, since the thermostat is not there to preheat the oil.
My latest improvement to the Tangerine Horizontal Cooling System incorporates a simple thermally actuated valve designed to allow airflow through the stock cooler only after reaching operating temperature.
Here's a pic of the prototype which will be operational in a few days.

[avidfanjpl]

I can confirm that running without the flaps operating on a 2.0L with Djet is bad in cold weather. Like ME733 said, maybe it is not so good.

My engine was rebuilt in 1978 with all the right parts but we did not hook up the bellows wire. Even with the car running warm enough it was easy to tell that it was running too cool. Would not accelerate right on cool days, and ran damn poor on cold days.

Changing the oil found enough bits from the main bearings to know that the car was being damaged from the constant NJ winter.

Sold the car, told the new owner to tear it down, but he wrapped it around a telephone guide wire in a bad turn even on a dry day within a week. Car was junked in 79, and no I do not have the VIN.

So much for not having the flaps working.

J

[Root_Werks]

I noticed this morning the engine was running "cool" on the temp gauge. Popped the lid when I got to work, yup the little cable worked loose. Gotta fix it.

Had that not happened to me this morning, I'm pretty sure I wouldn't have bothered posting to this thread. This has been hashed out so many times I've tossed my arms up in the air to it. People will do what they want anyway.

BTW - with my 914 running cooler and having carbs, it pretty much ran like poo the whole way to work. Never really warmed up to what I have things tuned to. FI will most likely compensate for the cooler running, but carbs generally don't.

Assuming your cooling flaps are installed correctly with the springs in place, if the cable came loose from the pinch bolt (or if the cable broke), the flaps would spring open to the "warmed up" position. Assuming your drive to work was at least 15 minutes, the engine oil should have come up to operating tempurature by then.

I think you may have a different problem, maybe with your carbs. I have my cooling flaps installed and connected to the thermostat. My engine running dual carbs runs fine right out of the gate and continues to run great after the oil is fully warmed up.

Correct me if I'm wrong, but the heads and the combustion chamber come up to temps pretty damn quick, like in a manner of minutes. Not sure how oil temps make the engine run like poo.

10.2 miles to work, as Zach also mentioned, heads temps can change quickly with load of the engine.

FI has a couple of sensors that allow the fuel ratio to be altered slightly to compensate for an engine running a little cooler than "normal". Carbs just can't do that.

"poo" refers to many stinky things, but in this case, just a little hesitation in the lower RPM's was all. (IMG:style_emoticons/default/biggrin.gif)

Alright, I'm done with this thread, promise this time. I'm too much of a dumb-ass to trust anything other than what the factory did for cooling. Best wishes to the rest of you who want to modify it, I'll stick with stock. (IMG:style_emoticons/default/beerchug.gif)

[DanT]

I love this topic every time it comes up

kind of like 4vs6 (IMG:style_emoticons/default/popcorn[1].gif) (IMG:style_emoticons/default/biggrin.gif)

[ME733]

The O.E.M. cast fan is efficient, and will cool off the engine just fine.

That's true up to a point, however the inability to increase fan rpm relative to crankshaft rpm means it is impossible to increase the cooling ability of the stock system beyond merely freeing up the airflow through the system.

There is another shortcoming of the stock system. The oil cooler always sees about the same airflow even when the oil is not up to temperature, since the thermostat is not there to preheat the oil.
My latest improvement to the Tangerine Horizontal Cooling System incorporates a simple thermally actuated valve designed to allow airflow through the stock cooler only after reaching operating temperature.
Here's a pic of the prototype which will be operational in a few days.

...............Chris....your going to get that damn flat-fan perfected to the point I,m not going to be able to live without it.(short-story) had a buddy with a flat-fan , carrera engine,550 spyder.(rare engine)...displacement was 1750. son-of a -bitch ran like a scalded dog..The flat fan of that engine just had a very special look., and...So does yours.

[brandomc]

Thanks guys. Im going to leave the system on the engine without the thermostat hooked up for right now. I live in LA, so i need to keep this engine cool. The car will also be in Bakersfield "devils armpit" alot, so it will be seeing 112 degree days.

[McMark]

(IMG:style_emoticons/default/thumb3d.gif)

[RiqueMar]

Fixed my photos descriptions above. These OK now? I got these photos somewhere, apparently the descriptions were wrong there too.

Those would be mine.....

brandomc, I did the same thing, as it never really get too cold here.

[mtc911]

This is a great thread - learned a lot. Inspecting mine it looks like the thermostat is gone - I think I know the answer but I’ll ask anyway - can this be our back together w/engine in car or does it need to come out?