[dennislarock]

I'm on the climate control air filter hunt and found Richards (DeliveryValve) posts and set up for fresh air but I haven't seen anything on a W123 in-cabin (recirc) air filter... I would have thought that some clever soul would have devised this by now or am not querying the search properly?

Direction, opinions please... and, thanks!

dennis

 

[DeliveryValve]

It's a tough area to work on. You really can't make it look elegant unless you do some major surgery to the HVAC box. Also depending on the filter, you'll get an air flow restriction. You might be able to just cut to size and wrap some bulk home HVAC filter in the area.

I decided at this point not to add in an inside filter. Partially because of the area and the other reason is my other vehicles don't have a factory interior filter, just a fresh air unit.

BTW- I really need to update that fresh air filter thread...
http://www.benzworld.org/forums/w12...w123-outside-air-cabin-filter-addition-2.html

 

[dennislarock]

hmmmm... so I guess that I will have to wait until I change the evaporator/heating core. I was thinking along the lines of a thin filter... of the type I use on the radiator of my computer. Those fans are 200mm x 2 so 200mm x 400mm filter, do not seem to restrict air flow very much but they sure catch a lot of dust and they are washable/reusable. If I get a free day maybe I'll pull the unit out of my wrecked 300D and investigate.

 

[DeliveryValve]

Pull the glove compartment out of your parts car. Then see how you can retro fit your computer filter in there and then test it on one of your running vehicles for airflow restrictions.
It would be interesting to see the results.

 

[dennislarock]

In your picture above is the recirculating flap on the right where I see the vacuum pod? Modifying the filter itself would not be difficult ...and, with a drill and a hack saw blade I could make a filter insertion slot without to much difficulty. Just trying to think of the proper placement... i.e., where to cut the slot into in the HVAC box... hmmmm.

 

[jackfrost1031]

That's the view from the glovebox with the liner removed. The flapper is on the right, the fan is behind the corrugated air duct, and the fresh inlet air comes from the left into the fan.

I've wondered where to add one, too. I changed the filter in my wife's car and it was chock full of shit after 60,000 miles

 

[dennislarock]

I feel your pain... I assume that after 30 years my evaporator must look like its been placed in a nice cozy woolen mitten. I only want to pull the dash once when I replace the evaporator and heating core so developing a way to keep them clean and operating efficiently is important to me. I am not certain what a difference it makes when new elements are installed but I have to believe its significant. My A/C is 38F at the center vent with the fan on 'low' during highway driving turn the fan on 'high' and its 56F... I expect a rise because of the airs resident time in contact with the evaporator ...but 18 degrees! Now, I feel grouchy.

 

[DeliveryValve]

In your picture above is the recirculating flap on the right where I see the vacuum pod? Modifying the filter itself would not be difficult ...and, with a drill and a hack saw blade I could make a filter insertion slot without to much difficulty. Just trying to think of the proper placement... i.e., where to cut the slot into in the HVAC box... hmmmm.

The recirculating flap is to the left of the vacuum pod. It is behind the number "33" writen on the side of the HVAC housing. As Jack pointed out the blower is below that behind the corrugated tube.

The problem of adding a filter there is the vacuum pod arm is in the way. Plus, I would feel the filter in that area would be too small to provide the air flow needed. My original thinking was to extend the air intake out to be able to house a nice sized filter.

.

 

[DeliveryValve]

...

I've wondered where to add one, too. I changed the filter in my wife's car and it was chock full of shit after 60,000 miles

Your wife's car filter is a fresh air filter.

Here is my install of one. I'll update it soon. Was lazy to do at the time.
http://www.benzworld.org/forums/w12...7-w123-outside-air-cabin-filter-addition.html

 

[dennislarock]

OK... Richard, I had been thinking about a vertical slot to the left of the number 33. I'm going to look very closely at D. Morrison's writeup and photos as well as yours tonight. In the morning I will go out and take a look, measure and calculate to see if I think its doable. I'll report back.

I also look forward to your finalization of the fresh air filter... as I will be emulating your pioneering efforts on that front as well.

Lastly, I cannot tell you how many folks I have sent your write-up on the '85 vacuum transducer/amplifier to in PMs... but it's well over 30... probably closer to 50. Nothing shifts like the '85. You are the Man!

 

[DeliveryValve]

Here is another view of the inside air inlet in the attached pic.

 

[DeliveryValve]

?...

Lastly, I cannot tell you how many folks I have sent your write-up on the '85 vacuum transducer/amplifier to in PMs... but it's well over 30... probably closer to 50. Nothing shifts like the '85. You are the Man!

Thanks, I wrote that up some time ago. Glad you are using it in helping folks out!

 

[dennislarock]

Excellent Photo! OK, a little rethinking and this is what I came up with. I'm headed out to measure the recirculation opening and build a frame that i will attach the filter/mesh to. The frame and filter will sit on top of the opening. The filter is semi-rigid... but, flexible. a seam will be cut into the filter to allow the vacuum pods arm to slide up and into a small hole in the filter that will allow the vacuum pod arm to travel unimpeded.

No, *this will not be* as efficient at eliminating dust as a paper filter... but it should allow for good air flow and if it traps *most* of the dust (as it does for my computer) I will be satisfied. Removing and washing it twice a year or so should be sufficient.

Thoughts... opinions ...please

dennis

 

[DeliveryValve]

Looks promising. It looks like just a mesh screen so airflow wouldn't be hindered, but just enough to catch the dust bunnies. Plus it has an added bonus of it being reusable. Heck, I might have you fabricate one for me too!

 

[dennislarock]

You are on Richard! My prototype worked pretty well but needs some adjustments. I put some tissue over it to emulate it getting plugged up and it sagged a little bit at the seam... so, i'll add a couple of braces.

OH!!!! I saw your post about adding a 'recirculation switch'... GENIUS! I live in New Orleans so your 'switch' and this filter should come in handy!

I need to get some more mesh and my wife's got an A/C issue with the '84D so it'll be a few days.

Here's a more accurate depiction... it just slides straight in.
(I have to adjust and finalize the dimensions)

 

[dennislarock]

Also... I see you do vegoil... here's my biodiesel 'Plant'

 

[DeliveryValve]

OT, that plant is hot!

Back on topic, looking forward to seeing pics of the new filter setup and how it performs.

.

 

[Noah Way]

Here is another view of the inside air inlet in the attached pic.

I've been struggling with removal of the remnants of a mouse nest on the firewall side of the core without removing the core itself. Among other things I've strategically drilled holes for insertion of vacuum and forced air with limited success.

Can you see any way to clean out the core while it's in the car? Maybe through the hood cowling?

More pics of the core would be helpful, thinking about access from the passenger side with consideration for internal plumbing.

Thanks ---

 

[DeliveryValve]

When you say core, do you mean the evaporator? Heater core?

If it's in the evaporator, can you remove the blower motor and peak up-across to the left. That would be the area the evaporator is and is nearest to the firewall.
Heater core would be front and center.

I'll see what I can do about pictures. I just need a bit more info.

 

[Noah Way]

The crud is behind the evaporator, if that's what is closest to the firewall.

I've dropped the blower, wedged open the dampers and sucked it out with a 1700 cfm dust collector. But the crud is on the bottom and the airflow passes over it instead of drawing it out. I tried pumping 90 psi air through from the front at the same time with no effect.

I've also plumbed the depths with a garden hose extension on a shop vac from a hole drilled as close to the core/evap as I could get. The problem is I can't control the hose, it goes in an arc and only hits the far side.

Can you get there from the cowl? Is there a spot near the bottom where I could drill an access hole without hitting a heat / coolant line?

Thanks ---