|
|
|
|
| Author |
|
|
Registered
Join Date: Jan 2006
Location: Santa Barbara, CA
Posts: 2,307
|
Heater Flapper Box and Valve (73 911.)
If you have heat on all the time in your early 911, you'll need to deal with the heater flapper box (that's what Pelican calls it) behind the rear wheel above and at the end of the heat exchanger. There are two of these; one at each rear wheel. Either the box is stuck so the inside valve is open, or the cable is misadjusted. I just pulled mine and cleaned it up. Seems to work fine. Took some pics which seem clearer than any others I've seen here. Note a few things: three bolts hold this on; they attach to three small studs in the body. They will be rusted in place and you don't one to break one off; soak these with penetrating oil or something before attempting to loosen the nuts. A long handled 10mm I think wrench with a ratcheting end will reach them. There are two valves here; the real work of blocking the blown hot air is done by the one inside the box; the other (butterfly) valve lets the hot air blow out into the airstream. Both valves are on the same axis; they must move easily. The inside valve needs to seal pretty tightly against the inside of the pipe to prevent hot air from entering the cockpit. The spring needs to pull tightly to close the inside valve fully. When reassembling, be sure the cable actually lets the spring do its full job or you'll have unwanted heat again. Apparently the 73 and earlier valve is different from the 74-86 or 89 valves though they appear to follow the same principles. There are other threads on this subject. Here's one I found useful. Heater flapper box  
__________________
jhtaylor santa barbara 74 911 coupe. 2.7 motor by Schneider Auto Santa Barbara. Case blueprinted, shuffle-pinned, boat-tailed by Competition Engineering. Elgin mod-S cams. J&E 9.5's. PMO's. 73 Targa (gone but not forgotten) Last edited by moneymanager; 01-17-2009 at 12:11 PM.. Reason: clarity |
||
01-17-2009, 11:33 AM
|
|
|
AutoBahned
|
nice pics
I'll add: be careful when taking the nuts off that hold these on - you don't want to snap off those studs you can also (and should) lubricate these in situ - I use HHS. - I've often wondered if these things could be ceramic coated to prevent rust... - also wonder if the newer ones will fit on the '73 and earlier cars... Last edited by RWebb; 01-17-2009 at 01:56 PM.. |
||
|
01-17-2009, 11:52 AM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Glad to see you figured out the problem!
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
01-17-2009, 12:54 PM
|
|
|
Registered
Join Date: Jan 2006
Location: Santa Barbara, CA
Posts: 2,307
|
Thanks. I'm not sure that it wasn't the cable pulling too tightly on the valve all along. I'm about ready to give it a try!
__________________
jhtaylor santa barbara 74 911 coupe. 2.7 motor by Schneider Auto Santa Barbara. Case blueprinted, shuffle-pinned, boat-tailed by Competition Engineering. Elgin mod-S cams. J&E 9.5's. PMO's. 73 Targa (gone but not forgotten) |
||
|
01-17-2009, 01:28 PM
|
|
