heater blower differences..

[911Jarle]

Hello guys!

This weekend, like mentioned before, I'm doing a lot of work on the 911.
Oil change, valve adjustment and also getting my heating system properly working.

I am however having some difficulties, recognizing what system I have, so I can get the proper hose from the heaters to my blower motor. The hose has been removed by previous owners..

From almost ALL pictures I see, the blower motor is in the middle of the engine compartment, by the air filter. On my car though, the blower motor is bolted to the left rear wing when facing the engine. At this stage, there are no hoses connected to the motor. Can anyone shed some light on what version of the system I have, and how it's supposed to work? On most engine pictures I see the hoses from the heaterboxes, connect to a collector beneath the blower motor, while on my car, they seem to collect in the fan shroud..

Hope anyone has some info that can help me out here.. Thanks!

Cheers, Jarle

[javadog]

Jarle,

It would help if you told us what year 911 that you have. It would be even better if you had a photo showing how your blower motor is mounted.

JR

[911Jarle]

Originally Posted by javadog

Jarle,

It would help if you told us what year 911 that you have. It would be even better if you had a photo showing how your blower motor is mounted.

JR

Hey!

It's a 1979 SC, and here is a picture of the blower motor itself.
Will take a good shot of the engine today as well..

Thanks, Jarle

[911Jarle]

Originally Posted by javadog

Jarle,

It would help if you told us what year 911 that you have. It would be even better if you had a photo showing how your blower motor is mounted.

JR

Here is a picture of the car, and also from the engine compartment.
The motor is behind the fuel filter on the picture...
A bit dark, but you should see it...

-10 here today, so I'm getting sort of desperate getting the heating to work





Thanks!

Cheers, Jarle

[javadog]

Jarle,

I don't know why your blower fan is located way back where it is but that is not where it is supposed to be located. I have attached a picture that I found on the internet that shows where the blower is located on a 911SC engine. You may have a few parts that you need to find and buy.

Even without the blower you can have heat. The early cars did not have the blower. If you search this site for "backdating the heater" you can see examples of how the various hoses are routed on cars that do not have the heater blower.

Cheers,
JR

[911Jarle]

Originally Posted by javadog

Jarle,

I don't know why your blower fan is located way back where it is but that is not where it is supposed to be located. I have attached a picture that I found on the internet that shows where the blower is located on a 911SC engine. You may have a few parts that you need to find and buy.

Even without the blower you can have heat. The early cars did not have the blower. If you search this site for "backdating the heater" you can see examples of how the various hoses are routed on cars that do not have the heater blower.

Cheers,
JR

A lot of stuff is different on my car. The fan shroud on front of the motor, is collecting the warm air from the heater diretly, and not a piping system on top of the motor like on that picture. The fan shroud is certainly original, looks like it anyway.

Then the fact that the motor itself is placed on the left rear wing. There is a hole in the wing, and there are bolts extruding from the wing to fasten the motor. All of it looks completely stock.

The problem though, is that the routing of hot air from the shroud to the motor is not there, and then I cannot find pictures of other SC's with the same setup.

Anyone out there have the motor bolted to the inner wing, or is my car the only one? A bit baffled over this..

Hope someone can shed a bit of light on this...

Cheers, Jarle

[javadog]

Jarle,

I am not aware of any differences in the heater system for countries with cold climates. I don't think there were any, so I can't explain what you have on your car. In your photo of the engine, you can see a large (~100-125mm) tube on the left side, near the ignition coil, that has been plugged. This is normally where the air supply hose that feeds the blower would be connected.

JR

[911Jarle]

Originally Posted by javadog

Jarle,

I am not aware of any differences in the heater system for countries with cold climates. I don't think there were any, so I can't explain what you have on your car. In your photo of the engine, you can see a large (~100-125mm) tube on the left side, near the ignition coil, that has been plugged. This is normally where the air supply hose that feeds the blower would be connected.

JR

Hey!

My car has been run in California, so it is not for a colder climate or anything.
The large tube you talk about, is the fan shroud. And in my case the fan shroud has an entrance for the hot air as well.

I'm thinking I should try to route hot air to the motor, see what happens.

Cheers, Jarle

[javadog]

Jarle,

Here's how it works:

The large black plastic duct on the left side of the red fan shroud is the source of the air for the heating system. The engine fan blows air into the fan shroud and some of it comes out the black plastic duct, instead ob being blown onto the tops of the cylinders. The air normally goes throught the corrugated black plastic hose into the left side of the blower fan. The blower fan outputs the air to the Y-shaped black metal piece pointing toward the rear of the car. This piece splits the airflow into two brown paper and wire hoses that pass through the sheetmetal that surrounds the engine and into the rear of the two heat exchangers under the car. The air is warmed by heat from the exhaust pipes in the heat exchangers and passes out the front of the heat exchangers, through a valve on either side of the car, then into the sills of the car. It goes through some additional hoses and valves in the front trunk, then into the car.

If you want, you can replace the black plastic duct on the left side of the fan shroud with a different part that allows you to connect the brown paper and wire hoses directly to it. There are a couple of versions of this part, which is why I suggested you look for a thread on "backdating" the heater, as it has been discussed many times on this forum. There is also a part that fit's into an opening on the right side of the fan shroud, which allows you to do the same thing.

JR

[Glenntpr]

I just got my 1983 911 sc out of Florida and the previous owner removed the heating blower, hoses, etc. I am not buying another blower and will use the "backdating the heater" option. Not very sure how efficient it will be, nevertheless is worth to try.

[javadog]

Here's one thread that might be helpful:

Backdating Heat - Questions?

JR

[911Jarle]

Originally Posted by javadog

Jarle,

Here's how it works:

The large black plastic duct on the left side of the red fan shroud is the source of the air for the heating system. The engine fan blows air into the fan shroud and some of it comes out the black plastic duct, instead ob being blown onto the tops of the cylinders. The air normally goes throught the corrugated black plastic hose into the left side of the blower fan. The blower fan outputs the air to the Y-shaped black metal piece pointing toward the rear of the car. This piece splits the airflow into two brown paper and wire hoses that pass through the sheetmetal that surrounds the engine and into the rear of the two heat exchangers under the car. The air is warmed by heat from the exhaust pipes in the heat exchangers and passes out the front of the heat exchangers, through a valve on either side of the car, then into the sills of the car. It goes through some additional hoses and valves in the front trunk, then into the car.

If you want, you can replace the black plastic duct on the left side of the fan shroud with a different part that allows you to connect the brown paper and wire hoses directly to it. There are a couple of versions of this part, which is why I suggested you look for a thread on "backdating" the heater, as it has been discussed many times on this forum. There is also a part that fit's into an opening on the right side of the fan shroud, which allows you to do the same thing.

JR

Air enters from the bottom hose, into the fan shroud, the fan air speeds it up to the motor on top, which again pushes this air through the heaters and forward through the sills. That's the theory yes?

So, I wonder why is my motor mounted directly on the wing? What's on the other side of the motor? Thanks for giving me a good explanation on how it should work, I'm just trying to figure out why my car has been modified like this. Anyone ever heard of this?

I will need to have a really good look around this weekend to see what has really been done here.

Thanks again..

Cheers, Jarle

[911Jarle]

Originally Posted by 911Jarle

Air enters from the bottom hose, into the fan shroud, the fan air speeds it up to the motor on top, which again pushes this air through the heaters and forward through the sills. That's the theory yes?

So, I wonder why is my motor mounted directly on the wing? What's on the other side of the motor? Thanks for giving me a good explanation on how it should work, I'm just trying to figure out why my car has been modified like this. Anyone ever heard of this?

I will need to have a really good look around this weekend to see what has really been done here.

Thanks again..

Cheers, Jarle

Looking at the picture it is clear what you mean. The bottom hose is normally feeding the heaters. The other outlet from the fan shroud is the feed to the motor..

OK, it seems there have been some sort of backdating here. My fan shroud is blowing directly through the hoses to the heaters like you mention. Thanks for clearing that up. But, I am having some difficulties understanding what my motor actually does at this stage...

On the back side of the wing, it seems there is a cooler of some sort. Earlier there has been a big big engine on this car, can it be additional oil cooler or some sorts get's air from the motor now?

And living in Norway, I am not entirely sure that this backdating business will give me enough hot air to last through the winter..

Anyone know how effective this is?

Cheers, Jarle

[javadog]

Originally Posted by 911Jarle

Air enters from the bottom hose, into the fan shroud, the fan air speeds it up to the motor on top, which again pushes this air through the heaters and forward through the sills. That's the theory yes?

No, that's not correct. The air enters through the main engine fan (the one that cools the engine), into the red fan shroud. A portion of this air is not sent to the engine but instead is sent out the black plastic duct on the left side of the engine, the one that is slosed off on your car. From there, it is supposed to go to the booster fan, which speeds it up and increases the volume of air that is sent to the heat exchangers.

There is not supposed to be another outlet on the back of the red fan shroud, going to the heater blower. If there is, it has been added by someone.

JR

[javadog]

Originally Posted by 911Jarle

So, I wonder why is my motor mounted directly on the wing? What's on the other side of the motor?

I can't answer this. I have never seen a car like this. I am guessing that a previous owner has modified your car and I don't know why he would have done that.

JR

[javadog]

Originally Posted by 911Jarle

And living in Norway, I am not entirely sure that this backdating business will give me enough hot air to last through the winter..

Anyone know how effective this is?

Cheers, Jarle

If you drive at higher engine speeds, usually the heat from the engine fan alone is enough, provided you don't have any air leaks in your car. Porsche added the additional fan to boost the heater output at low engine speeds. If you drive a lot in the city, you will probably want the additional booster fan.

It would be interesting to see more pictures of your car. Perhaps we can figure out what has been done.

JR

[911Jarle]

Originally Posted by javadog

If you drive at higher engine speeds, usually the heat from the engine fan alone is enough, provided you don't have any air leaks in your car. Porsche added the additional fan to boost the heater output at low engine speeds. If you drive a lot in the city, you will probably want the additional booster fan.

It would be interesting to see more pictures of your car. Perhaps we can figure out what has been done.

JR

After looking a bit more on my car during the weekend, I think I understand what has been done.

1) A complete backdating seems to have happened on the heating system. Both hoses connected to the heater boxes are routed directly to the fan shroud.

2) The el motor is mounted directly to the inner wing, blowing directly on the aircon radiator under the wing itself. Probably to get a colder blowing aircon.

Anyway, my heater levers don't work. The wires look complete by the heater boxes. Do they let go by the lever usually, or do the wires break inside the rubber protection? Easy to change?

Thanks guys!

Cheers, Jarle

[Grady Clay]

Jarle,

First mission is to get the levers to open the heat control boxes.

If you have some issue with the controls or cables, simply wire the control boxes open (they are spring-loaded to close). Heat is critical at -10 (F or C doesn't matter). If it is too hot, open a window. Don’t let too-hot air to the defrosters, you can crack the windshield.

Make sure they open by looking up at them. (The waste-air vents should be closed.)

While there, confirm the red heat hoses from the heat exchangers to the control boxes are intact.

Even with back-dated heating system, you will get lots of heat simply keeping the rpm up.

Best,
Grady

[911Jarle]

Originally Posted by Grady Clay

Jarle,

First mission is to get the levers to open the heat control boxes.

If you have some issue with the controls or cables, simply wire the control boxes open (they are spring-loaded to close). Heat is critical at -10 (F or C doesn't matter). If it is too hot, open a window. Don’t let too-hot air to the defrosters, you can crack the windshield.

Make sure they open by looking up at them. (The waste-air vents should be closed.)

While there, confirm the red heat hoses from the heat exchangers to the control boxes are intact.

Even with back-dated heating system, you will get lots of heat simply keeping the rpm up.

Best,
Grady

Thanks for chiming in. How do I wire them open if I may ask?
Remove the springs? In case the control wire has broken or something this is what I'll do temporarily.

Cheers, Jarle

[JJ 911SC]

Originally Posted by 911Jarle

Thanks for chiming in. How do I wire them open if I may ask?
Remove the springs? In case the control wire has broken or something this is what I'll do temporarily.

Cheers, Jarle

Driving under the same condition...

Remove the spring and close them (I'm talking externaly while Grady is talking internaly, same difference, when you look at them you should not see inside the pipe). Now the heat going inside the car.