924Board.org

svandamme · Joined: 01 Oct 2005 Posts: 7 Location: netherlands

can anyone tell me if the 944 heater blower is a drop in replacement for the 924 one? when it's cold, the top of my windshield never defrosts , the blower just doesn't cut the mustard

i've heard of a certain replacement upgrade , but not sure what donor is suitable , or how easy/difficult the upgrade would be...
_________________
Stijn Vandamme
'73 911 2.4 S Targa 9113310111
'77 924 9248100128 *sold!*
'85 944

" we're your friends
we're not like the others man , really."

AGD931 · Joined: 17 Mar 2003 Posts: 289 Location: Athens, Greece

The 944 heater blower is not a drop in replacement for the early 924 one. I am assuming that the 924 in question is the 77 in your signature.

The reason is that the heater box assembly is different and the 944 heater blower does not physically fit into the 924 heater box. I know this because I tried it.

I suspect the upgrade that you mention, would be to remove the dash and change the heater box for a 944 one and of course the switch panel.

I have read road tests of the 944 and the opinion was that the ventilation system in general was not one of its plus points.

Arthur
_________________
1981 931 S2
1990 E30 320i Cabrio
1979 Ford Capri Ghia

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

Not sure if I've posted this here before, but here are the notes from my website. Short answer is, it's a major improvement, but also an incredible headache.

The Heater
This was the big project- updating the awful 931 heating system to the much improved early 944 system. The conversion is painful at best. Here is the list of what needs to be replaced-

-944 Center console (different heater conrol mounts)
-944 Center gauge panel (also has different clips for the heater faceplate)
-944 Control face plate
-944 Slider assembly
-944 Fan switch knob (off-1-2-3)
-944 heater box & blower
-944 heater motor cover in the engine bay
-944 heater box mount (center mount)
-944 heater core
-944 under dash ducting
-944 heater control valve (it operates opposite the 924 valve and has more range, also has larger hose connections- you'll need a little grease on the hoses to slide them on).

The biggest problem with the conversion is that the 944 battery shelf is cut differently than in the early 924's. The hole cut through the shelf that the blower pulls fresh air through is set about 1/2" frontwards of the 924 hole. In order for the larger 944 heater blower to clear the windshield wiper mechanism, windshield sheetmetal, and dash and trim, the hole in 924 shelf has to be moved forward by this 1/2". I ended up cutting a box around the perimeter of the hole on the 924 shelf, removing 1/2" from the front of the box I cut just in front of the hole, then reattaching the box onto the shelf and adding 1/2" of aluminum spacer to the rear of the box where there was now a gap. Next tack weld as much around the perimeter of the box as possible and fill in the remaining gaps with JB Weld or equivalent. Unfortunately, it's just too tight to weld around much of the area. In the pic to the side you can see the left over JB Weld around the perimeter of the hole. Now everything lines up perfect and the 944 heater box will slide right in.

nick

svandamme · Joined: 01 Oct 2005 Posts: 7 Location: netherlands

Thanks guys, but if it's that difficult, i think i'll pass
especially considering my track record on getting things disassembled and reassembled eg , never less then a year between

i need at least some blower when it's cold over here

i'll have a look if there's nothing else i can do to improve my blower
_________________
Stijn Vandamme
'73 911 2.4 S Targa 9113310111
'77 924 9248100128 *sold!*
'85 944

" we're your friends
we're not like the others man , really."

Joes924Racer · Posted: Fri Oct 07, 2005 5:58 am Post subject:

I just getting to ordering replacement parts for mine
cause itll leak if I hook up the
heat exchanger ..So thats 2 sealing rings # 021-101-173
& 1 connecting flange heat exchanger # 477-819-869.

Should get the hose though Imade replacements with some reouting
new hose are to much money if I remeber right off hand... next thing you know
itll be X-mas.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

Joes924Racer · Posted: Fri Oct 07, 2005 2:44 pm Post subject:

sealing rings are 4.50 cents apiece
connecting dflange is about the same..
Ithink the hoses that go there are like 30 bucks each,
I made my own.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

Smoothie · Posted: Sat Oct 08, 2005 1:40 am Post subject:

Someone here had a problem with low output from the early style heater that included weak defrost. As I recall, there was a problem with the air inlet flap that's visible from the front with the hood opened. I think the problem there was that it was sealed shut by a too-liberal application of sealant. -So you could check that and see that it opens/closes as it should - I think the same lever that controls fan speed also controls that flap. If it's ok, check the operation of the other flaps.
I have the late-924-early-944 hvac system and though it's different from yours, had a problem that could occur with any automobile heater... Heat output was poor and after living with it for quite a few years, I finally found that one of the lines to it was clogged shut by radiator stop-leak. That just needed to be flushed out, now the heat output is more than I need. Obviously this was just a heat problem though, and there was no problem with the blower airflow.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

svandamme · Joined: 01 Oct 2005 Posts: 7 Location: netherlands

i'll check that, got some other stuff to deal with as well, my ignition key is acting all funny since this morning , flips back to off when i turn it on
flips back to on when i turn it off... looks like i'll be replacing that over the weekend...

it's my own fault really , i was stupid enough to fix all faults 2 weeks ago
the Porsche gods don't like it when there is nothing broken on the car... so they find something new for me to replace

_________________
Stijn Vandamme
'73 911 2.4 S Targa 9113310111
'77 924 9248100128 *sold!*
'85 944

" we're your friends
we're not like the others man , really."

Smoothie · Posted: Sat Oct 08, 2005 3:52 am Post subject:

Here're some past posts on it -
this one includes a pic by CMXXXI of the earlier hvac - http://www.924board.org/viewtopic.php?t=13312
outer flap sealed shut problem - http://www.924board.org/viewtopic.php?t=13521
other heater problem related stuff -
http://www.924board.org/viewtopic.php?t=11056
http://www.924board.org/viewtopic.php?t=12730
http://www.924board.org/viewtopic.php?t=13968
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox