Heater Box air flaps

Jockomo · Posted: Sat Jun 23, 2012 8:43 am Post subject: Heater Box air flaps

I am missing the air flaps for the heater box.
I don't need the heat in the bus.

Should I close them off and run the heater fan all the time to blow the heat out of the exchangers? (is the fan supposed to run all the time? or just when you need heat)

Can I leave them open and close off the tubes that come from the fan, then not have to run the fan to cool the exchangers? That's actually how I have run it in the past.
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'75 Westy with '78 2.0L engine.

busdaddy · Posted: Sat Jun 23, 2012 9:30 am Post subject:

Exactly which flaps are we discussing? the non return flaps at the bottom of the shroud?, the non return flaps in the booster fan? or the flaps in the control valves at the front?
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jmstu76 · Posted: Sat Jun 23, 2012 9:31 am Post subject:

Why not just leave it alone as it was designed and don't turn the heat on since you don't need it?
_________________
James

'76 Deluxe Sage Green Westy
2258 cc GD case 78mm CW crank, 2.0 H-beam rods 5,325” 22mm pin, JE forged pistons with 15cc dish, JE rings, type 11 clearanced oil pump, CB Eagle 2205 Type-2 “Torque Special” hydraulic cam with matched lifters fed by CB Dual Weber 40 IDF MX with 6” foam air filters, currently 55 idle, 130 main, 200 air correction, 32 mm venturis. 27in General Grabber AT2 All Terrains, Berg Shifter, stock '76 exhaust HPC Ceramic Coated. 11/18/2020

Jockomo · Posted: Sat Jun 23, 2012 9:48 am Post subject:

The ones in the bottom on the fan housing.

#2 on ratwell's

jmstu: because I don't have the flaps.

As far as I can tell, they only come into use if the fan is on. I guess my question is, can i ditch the fan, as long as i cover the holes that bring air into the heat exchangers from the fan tubes?
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'75 Westy with '78 2.0L engine.

busdaddy · Posted: Sat Jun 23, 2012 10:23 am Post subject:

You don't really need the lower flaps, they are an evolutionary throwback from the 411/412 and really don't do much in a bus. You do need the flaps in the booster fan or if you remove the booster fan you have to cap the tubes so hot air doesn't blow into the engine compartment.
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Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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Jockomo · Posted: Sat Jun 23, 2012 10:26 am Post subject:

Perfect. Thanks once again Busdaddy!
_________________
'75 Westy with '78 2.0L engine.

KlassicBus79 · Posted: Sat Jun 23, 2012 10:39 am Post subject:

Thanks for the info Busdaddy.
One of my lower flaps is missing and the only place I can find it is German Supply, but I haven't ordered it yet because I'm not sure if the pin and spring come with it.
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79 Cal Transporter 2L

udidwht · Posted: Mon Jun 25, 2012 12:35 am Post subject:

tootype2crazy · Posted: Mon Jun 25, 2012 5:06 am Post subject:

You can make the flaps easily with a piece of lightweight tin from something like a pie pan. Just cut them to the desired shape, roll the area for the pin and set it up against the shroud and hammer it into shape with a ball peen. U can use a piece of wire or a large paper clip for the pin.
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

KlassicBus79 · Posted: Mon Jun 25, 2012 8:33 pm Post subject:

Absolutely correct about the spring. I just finished working on the guard on my lawn mower just before I wrote that. Embarassed

_________________
79 Cal Transporter 2L

Wildthings · Samba Member Joined: March 13, 2005 Posts: 52791

All the little flaps on the outlets of the fan shroud do is break off and clog your heat exchangers. They had a purpose on 411/412s which had gas heaters that could be run with the engines off, but no purpose that I know of on a bus engine.

As mentioned above you do need the flaps, hoses, and stuff for the aux fan, or you need to close off the tubes going down into the heat exchangers. If you have your heat exchangers off then having the ports where the tubes attach welded up is a good option, but you can also easily close off the tops of the tubes with freeze plugs, metal tape, etc.

LeeE · Posted: Tue Jun 26, 2012 11:26 am Post subject:

Image may have been reduced in size. Click image to view fullscreen.

Easy to make, and a finishing nail is perfect for the pin.

I removed the fan and hoses completely. I capped the heat exchanger inlets and covered the holes in the tin with pieces of can metal. Cut one piece to fit over the hole and another for a brace underneath, screw them together loosely, bend and fit them tightly into place and then tighten the screws to snug them.
_________________
1978 Westfalia stock 2.0 FI
Welcome to the Okeedokee Swamp

whatdoesthisbuttondo? · Posted: Tue Jun 26, 2012 1:04 pm Post subject:

Gatorbus · Posted: Tue Apr 16, 2013 11:17 am Post subject: Heater non-return flaps

Old post resurrected. Sounds like these fan shroud lower non-return flaps aren't too critical, but are they essential if I want to have my heater working properly and stink free? And what controls the flaps since they have a pin/hinge incorporated? What position do they take with the heater on or off? Goal is to get my heater working as close to stock.
_________________
1973 Automatic Transporter
2.0 with Weber 32/36 DFEV progressive

Wildthings · Samba Member Joined: March 13, 2005 Posts: 52791

They are open any time the engine is running, whether the heat is on or off. To the best of my knowledge they have zero effect on the heat output, either temperature or volume. The only purpose I can see them serving on a bus is that of a one way mouse door. Don't know if that is good or bad though.

SGKent · Posted: Tue Apr 16, 2013 1:33 pm Post subject:

If the electric fan RPM was a higher output at idle than the cooling fan it would prevent back flow.
_________________
Rolling Eyes

Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand). Rolling Eyes

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice" Rolling Eyes

1971 deluxe (sold)
1977 deluxe

Gatorbus · Posted: Tue Apr 16, 2013 1:42 pm Post subject:

edhnb · Posted: Sat Mar 30, 2024 2:52 pm Post subject:

Whaanga · Posted: Sun Mar 31, 2024 2:23 pm Post subject: Re: Heater Box air flaps

Does anyone have a photo of the flaps connected to the booster fan?
_________________
Late 1973 Bay w/a transplanted 914 Engine


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