Air Blower Fan Numbers (Degrees)

[SylvainC]

Hello, would anyone know what the numbers (degrees) on the rear of the fresh air blower (squirrel) are for and how they work.
Thank you in advance

[76FJ55]

Not sure I understand what you are referring to. Can you post a pic?

[proporsche]

Originally Posted by SylvainC

Hello, would anyone know what the numbers (degrees) on the rear of the fresh air blower (squirrel) are for and how they work.
Thank you in advance

welcome..but..you need to provide more of our info..what 911 do you have..plus picture would help what are you looking for..
to insert picture go to the bottom to Advance in blue ...

ivan

[EC900]

In the meantime until more info is submitted, could this be of any help and since I never had taken apart a blower motor for closer examination. There may be an old label/sticker you’re finding that probably is some sort of quality control or lot number printed on it, other than that maybe it’s the manufacturer mold or assembly numbers imprinted on the cage itself.


❤️ Love 911 Jeopardy.

I’ll take Blowers and Fans for $100
Often referred to as a squirrel cage, this fresh air blower fan has a common blade pitch.

What is 20 to 30° ?

(Reference - ballpark from eyeballing a URO replacement 17 blade blower motor 911.571.320.32 )

If you need it, here’s the owners manual on how the blower works in conjunction with the heat blower in the engine compartment;

[SylvainC]

[SylvainC]

[EC900]

Wow, that’s looks old.
I don’t think those values are related to installation.
However given the German penchant for engineering, might it be a unit circle for a trigonometric function ? Conversion reference for converting degrees to radians…for what, who knows. Puzzled here.

[SylvainC]

Hello, thank you to those who have replied to my inquiry. My air blower fan assembly was removed from a 1970 911. I believe it to be original. I replaced the air blower/motor assembly with a Gen Porsche (OEM) assembly. I believe that this replacement assembly part # 911.571.320.32 is said to be usable for 65-89. Interesting to note that the new OEM replacement assembly also has similar numbers/degrees on the rear of the squirrel/hamster base (not clear from my picture due to the reflection but they are there), while from my research URO replacement assemblies have no such numbers/degrees on the base. The OEM replacement is presented as being sold balanced. The balancing is achieved with the movable wire clips attached to the fan blades. I am taking a wild guess that the numbers/degrees perhaps serve as a compass to assist one in the unpleasant task of balancing if required, example if one replaces only the motor, which can be done. I do not believe the numbers to be related to output. Does this make sense?

Thank you in advance for any further commentary on this subject.

[proporsche]

i would bet it was for balancing purpose of the fan....
i did 2 jobs recently and both times the white fan was absolutely out off balance-had to return it and informed the supplier about it.

Ivan

[76FJ55]

Originally Posted by SylvainC

Hello, thank you to those who have replied to my inquiry. My air blower fan assembly was removed from a 1970 911. I believe it to be original. I replaced the air blower/motor assembly with a Gen Porsche (OEM) assembly. I believe that this replacement assembly part # 911.571.320.32 is said to be usable for 65-89. Interesting to note that the new OEM replacement assembly also has similar numbers/degrees on the rear of the squirrel/hamster base (not clear from my picture due to the reflection but they are there), while from my research URO replacement assemblies have no such numbers/degrees on the base. The OEM replacement is presented as being sold balanced. The balancing is achieved with the movable wire clips attached to the fan blades. I am taking a wild guess that the numbers/degrees perhaps serve as a compass to assist one in the unpleasant task of balancing if required, example if one replaces only the motor, which can be done. I do not believe the numbers to be related to output. Does this make sense?

Thank you in advance for any further commentary on this subject.

I'm pretty certain it is a balance reference. as you can see the it is 360 deg divided into 45 degree increments. I'd guess the the black line is the optical reference for the balancing machine and is located at 0 deg. the machine would then calculate the necessary added weight and degree location for the installation of the metal clip balane weight.

[SylvainC]

Thank you for the replies

[UROParts]

Quick update on these blowers: our engineers checked 100% of inventory and scrapped all units that were unbalanced or wobbled. There could still be unchecked units on retailer shelves though, so please email us if anyone gets a bad one.

Manufacturing improvements are being made, and hopefully we'll have a new production run by this Fall.

[EC900]

Rely to @URO Parts :

I bought this from PP (maybe 2022 or ‘23) as a spare and haven’t installed it yet since old one still operates and hasn’t been screeching anymore.

For example of what your update refers to…is the silver tab on one of the vanes be an indication this fan was balanced and the QC sticker be the approval of the new or inspected production models as of 10/2022 ?

Thanks for the product update!

[UROParts]

Hi EC900, there's no way to know for sure if that blower was affected, but if the cage has runout/isn't balanced, just contact "sales at apa industries dot com" with your details and a copy of your order confirmation to start a warranty exchange.

[proporsche]

URO -good job getting this right -i suppose Rosepassion already have the new balanced ones;-)

Ivan

[Mtsurfposse]

A URO fan just arrived at my door. how do I check it for balancing before installing? Attach a few leads to it and the battery and run it for a few minutes and see if it gets wonky?

[proporsche]

Originally Posted by Mtsurfposse

A URO fan just arrived at my door. how do I check it for balancing before installing? Attach a few leads to it and the battery and run it for a few minutes and see if it gets wonky?

yes...