Flapper in heater fan, What does it do ? |
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Flapper in heater fan, What does it do ? |
Olympic 914 |
Jul 3 2017, 07:46 AM
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#1
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Group: Members Posts: 1,675 Joined: 7-July 11 From: Pittsburgh PA Member No.: 13,287 Region Association: North East States |
The heater fan motor was pretty cruddy so I disassembled it and polished the armature and greased the ends then bench tested it and it ran pretty good. loosened the bolts on the housing and while it was running wiggled it around a bit until it ran the smoothest. when I reassembled it I noticed a clear plastic flapper inside the blower housing. No spring on it to hold it closed. When I put the fan in the car with the outlets pointed in what looked to be the best direction, pointing towards the pass side, the flapper valve hung open.
Looked at the "originality photos" and see that the outlet was installed to point straight up (?) in this position the flapper closes by gravity and would open whenever the fan is blowing. What does this flapper do ? |
malcolm2 |
Jul 3 2017, 08:17 AM
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#2
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Advanced Member Group: Members Posts: 2,747 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States |
My guess is that it keeps "stuff" out of the blades.
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BeatNavy |
Jul 3 2017, 08:21 AM
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#3
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
Or maybe to keep the engine fan from pulling hot air out of the heat exchangers into the engine bay (IMG:style_emoticons/default/confused24.gif)
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rhodyguy |
Jul 3 2017, 08:26 AM
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#4
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,092 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
Outlets, plural? Are you using an early fan?
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Olympic 914 |
Jul 3 2017, 08:59 AM
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#5
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Group: Members Posts: 1,675 Joined: 7-July 11 From: Pittsburgh PA Member No.: 13,287 Region Association: North East States |
Outlets, plural? Are you using an early fan? Original '73 fan with single outlet mounted in original location. but installed a dual outlet adapter from a later model (I believe) To hopefully increase the heat. Or maybe to keep the engine fan from pulling hot air out of the heat exchangers into the engine bay (IMG:style_emoticons/default/confused24.gif) This could be the answer. (IMG:style_emoticons/default/beerchug.gif) I did mount the housing so the flapper would be closed by gravity when the blower is not running. |
rhodyguy |
Jul 3 2017, 09:16 AM
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#6
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,092 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
Your car should have a single outlet fan with a splitter for the hoses if you want heat to both sides. The cooling fan pressure should close the little door as engine speed increases. I don't bother with a aux fan. I just cap the jtubes with a couple of 2"(?) rubber pipe caps from the hardware store.
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malcolm2 |
Jul 3 2017, 09:35 AM
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#7
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Advanced Member Group: Members Posts: 2,747 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States |
Or maybe to keep the engine fan from pulling hot air out of the heat exchangers into the engine bay (IMG:style_emoticons/default/confused24.gif) I hear that that is what the flappers on the engine fan do. But if gravity is holding down this flapper, I suppose HE air could make it's way to the engine bay if the flapper was not there. Probably more of a chance that would happen than my "stuff" idea. Cause where is the "stuff" going to go if it is sitting on top of the flapper. (IMG:style_emoticons/default/confused24.gif) |
McMark |
Jul 3 2017, 01:01 PM
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#8
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Factory diagrams show the fan outlet pointing damn near straight up. Well, more vertical than horizontal anyway.
Attached image(s) |
Olympic 914 |
Jul 4 2017, 06:56 AM
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#9
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Group: Members Posts: 1,675 Joined: 7-July 11 From: Pittsburgh PA Member No.: 13,287 Region Association: North East States |
Factory diagrams show the fan outlet pointing damn near straight up. Well, more vertical than horizontal anyway. That's the way I have it mounted now. It will only rotate to vertical so far then the fan housing contacts the relay plate. Interesting picture. what do you think the white block is wire-tied on the side of the motor? Maybe a block of felt or something to cut down on noise? I have not seen this in any of the "originality" pictures. |
McMark |
Jul 4 2017, 07:52 AM
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#10
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Here's all I see in the manuals:
QUOTE A suppressor is attached to the blower motor in vehicles equipped with a radio. ANDQUOTE The suppressor, if installed, should be connected in the same way to both cable ends. The plastic cover must be pushed back over the suppressor in such a way that all connectors are covered. The suppressor should be reattached to the blower motor with a plastic hose clamp (at least 250mm long). It's not uncommon on cars from this era to have noise suppression on most electrical motors and other EMI-noisy devices. So this suppressor was probably part of the original design, but didn't make it into any production cars. |
Spoke |
Jul 4 2017, 08:44 AM
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#11
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Jerry Group: Members Posts: 6,991 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None |
When the heating fan is not on, the engine cooling fan provides air to the heat exchangers to 1) heat the cabin or 2) to cool the exhaust pipes when heat to the cabin is shut off by the HE flappers.
The flapper valve in the heating fan keeps the air pressure from the engine cooling fan from blowing back through the heating fan thus maintaining pressure and airflow through the HEs at all times. |
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