348 recirculation door for the HVAC is non functional

lol, Yes... I understand it looks just like that picture with a big hole and the blower inside but INSIDE there I see no evidence of flap or so it seems. Maybe it tucks clean against the wall and it looks like the wall but its actually a flap or something. Never mind I am not being clear. I'll pull it out and figure it out.

 

Ah.. yes.. sorry... same happened to me. It looks like a wall and might be difficult to recognise.

 

The flap might be sitting squarely on the bottom of the evap box and 'looks' like the floor of the box. When mine broke off, that's how I found it -- but I too thought it was entirely missing from the car. Inside the evap cavity, push your fingers or a slotted screwdriver around the edge and see if it's down there and just needs to be tilted/prised/lifted out.

 

Darn I was afraid if that guys, I was hoping it gets stuck to the side. The bottom has a raised oval section which is the bottom of the box, so no flap in my box.

Anyone have a solution I did not see it as a line item part to purchase.

 

I am going to have some cnc'd out of aluminum, with a hollow frame flap that we can attach abs to to make it lighter. I'll make a handful and other members who need them can have them. I need some help since I don't have a flap, I have no idea how it operates can someone help explanation of how it operates, from there I can measure and workout the clocking with the boss that I can see earlier in this post at least.

Is this correct looking from the side?
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A lot of the weight comes from the high density foam (neoprene rubber?) on either side of the flap, but aluminium would be good. I'm not sure why they made it so heavy (sound deadening? less resonance?)

I can't remember if the hollow spindle (tube) of the flap extends past the flap on the windscreen side and sits in a groove....or if has a locating pin in the end. You can probably see what it sits in.

The "D" shape brass boss/drive (from Ricambi or Hill Engineering) slots into the spindle (i.e. into flattened end shown in the photo). You'll probably need the brass boss for dimensions, I guess (unless the plastic one is still intact).

I think what you've drawn in green is correct (for the path it takes), but better have someone else confirm it.

 

I have a flap and its pin sitting on my desk in the garage. I can get measurements and photos this evening.

 

wow thats great. ill get the brass boss and measure that too. ill put up a prelim cad render later tonight so you can see what i mean by hollow frame. superlight.

I will make a dozen, when i do you get one Wade as a spare for the help.

 

I do not have dimensions yet, I can pull the box get it on a bench and mock it unless someone can get me dimentions but thinking something like this with some lightening slots.
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Okay, here's what I have. I'm not a drafter so if you have any questions, let me know.

All measurements are mm.

Not shown, the foam material is 5.5 mm thick.

The structure is actually formed from a single sheet of steel.


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.

 

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Ahhhhh I see what they did there, it's a thin metal flap with foam glued to it. Ok let me noodle on that I think that is way cheaper to make. The cnc aluminum one I mocked before seeing it is over engineered and cost like 400 a piece.

 

I just found this thread which shows a photo with the door installed.

https://www.ferrarichat.com/forum/threads/348-climate-control-issues.203394/

 

Here's the upgraded pin that interfaces the door and the motor.

Part #: RC348348/355 Air Re-circulation boss

 

I have lots and lots of Mig welding experience but no Tig. This may be an excuse to get a tig....

What a cheap piece of crap that OEM door is.

Thank you much Wade.

 

Yes, except for the foam, it's 1890s technology.

Not sure where or what the welding is for...

 

The rubber/foam seems to be the same thickness as the diameter of the tube. Perhaps it needs to be this thick because of the geometry of the box and the surfaces it needs to contact?

Without thick rubber, would it look like this with only one contact point?
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Wade, your dimensions show a tapered flap. I wonder if they are all like this?

 

Ahh well... a flat aluminum plate about $12 can be welded to an aluminum tube about $5 and replicate the steel flap the foam is glued to. The 2 ends can be turned on a lathe and pressed in.

 

The flat part, where the foam is, is generally equal at 103 x 170. The tubular section is somewhat tapered, probably due to the crimping at one end and the pin inserted in the other.

Also, the thickness of the flap and foam is just a bit thicker than the tube.

 

Okay, way too simple. lol

BTW, only one end is pressed in, the other is inserted onto the motor first.

Photo courtesy of Ricambi America.

 

Yep I see that. What I mean is a fitting to fit the brass boss would be pressed into a tube. I am going to order a new motor and boss, get those measurements combined with yours and go from there. It is tapered due to the crimp.

 

As a FYI, the weight of the flap with foam is exactly 13 oz.

 

Yep that's why in my first cad render above I had the flap offset to the OD of one side of the tube, I could see that right off the bat.

 

I wouldn't worry much about the weight of the flap although making one of aluminium would be an elegant solution. What actually brakes the plastic coupling is the fact that the servo-motor is stalled in the flap end positions so the torque from the motor, which is quite high due to the motor's internal reduction gears, breaks the coupling (or strips the plastic reduction gears inside).

Unlike the servo-motor for the cabin air direction, the servo-motor for the air recirculation flap does not have a potentiometer for feedback to the AC ECU to know when to de-energise the motor so it runs until it is stalled by the flap hitting its end of travel. Perhaps the AC ECU de-energises the motor based on its overcurrent in the stalled condition but I doubt it - it seems that the flap motor remains continuously stalled applying significant torque on the flap spindle. One way to check this is to close the flap and watch the motor - it will twist somewhat in the opposite direction (as it has rubber bushes on its mounting screws) at the moment the flap closes; then see whether, after some time, the motor relaxes back or stays stressed.