How did you bend the spring anchor? I started to bend mine and the top sheared off. I think I can dremel another notch so the spring stays put, but it seems primed to break rather than bend.

My valve is 1/2 to 2/3 closed after hours in freezer. Is it possible that’s normal? Based on the discoloration, it seems that it never spent significant time fully open.

 

at this remove in time I dont recall how I bent it - it wouldnt have been very much.
jp ex 83 Euro S

 

This is my valve. Just slightly open too much here in the garage at 20 degrees C. To make it serviceable I drilled out my rivets and used M5 bolts, almost no extra drilling required. I also did "tune" the bimetal plate by bending it VERY carefully to reach desired rpm from cold start. I used a flat noseplier, squeezed it a bit down on the plate, and bent it at the same time to spread the load on the metal. My plate obviously did not break so i cannot say why yours did shear off. Metal fatigue maybe? I also did test mine with external power to the heatcoil before mounting it. About 6-7 minutes to closed. My car is a 1983 928s Euro K-jet.

 

How much should it be opened at
20 degrees Celsius?
0 degrees Celsius?

I am trying to figure out the basic setting of
the AAV

Is this a correct opening at 20 degree Celsius:

 

If it were on my car that would be too small opening = too low rpm on startup. But you have a L-jet so I cannot say if it is directly comparable to mine. Some other with a L-jet would have to chime in here...

 

I have a CIS Euro 928S. I can already confirm that this AAV is the original one that came with the car.

 

Sorry for this, misread the answers and questions above, my bad. If your car is a CIS then my earlier answer should apply to your car also..

 

This is my AAV at 2 degrees Celsius :

 

That doesn't look right at all, too small opening. Considering the Bosch number, your valve should behave exactly or similar to mine. I have tested my valve in almost 0 degrees C and it should be open as much as in my picture or maybe just slightly more than that.
If you click at my picture you can zoom in and look into the valve at the opening in the disc. At 20 degrees celcius, the sharp point/tooth you see to the right on the disc should be about 1,5mm closer to the right wall. But again, these are analogue and dynamic systems so my setting is not guaranteed to work to the point with your car. Very recently I adjusted my valve and also did a new setup of the mixture and idlescrew. It is very nice on the idle rpm and no "bounces" when you quickly rev up release back to idle...

 

I made some tests of my AAV and this was the result:



AAV @ -2 degree Celsius


AAV @ 26 degree Celsius

So this is quite a difference with pic in first post.
There the opening at 26 degrees is like mine at -2

 

A little story here, I had a 74 2.0L 914 with the Bosch fuel injection, the cars were noted for engine fires due to old injector tubes and poor starting issues. The “Fix” was a the carburetor swap out. So mine had the poor running issues, so the only foreign shop in town was a MB indy (1991) so I stopped by and asked him if he would put the carb kit on for me. He would not do it! Said my only problem was the block temp sender and the AAV. The AAV cokes up inside and fixes to one setting, not open or closed all the way, so he soaked it all night in a jar of gas and shook it up real good and let it dry. It worked fine after that, it was not electric but worked off engine block heat. It looked like the AAV on our cars but just no plug. So you might try the overnight soak and see if it opens and closes with cold and heat.

 

hi, thanks for the advice. Problem is not that it doesn’t close or open but that opening might not be correct at certain temperatures,…and that it perhaps closes too soon when warming up.

 

Up date the 914 AAV was also electric but engine heat would close it.

 

I wouldn't use the "soak" method. It's going to leak inside and if it's dirty, the dirt's going to stay inside + the heatcoil could be shortened out with fluid and dirt. Drill it open and clean everything inside. It's really easy. The wires to the heatcoil are pretty small so be gentle when you open it. The valve is also springloaded so i use a thin screwdriver and hold it in the hole against the valve to relieve pressure on the disc. After you have removed the rivets and hold the disc it easily falls apart in two pieces. After it's clean you can do a bench test it with 12V to the heatcoil. Should close fully in about 6-7 minutes from 20 degrees C ambient temperature. I think this would be good in order to get a startingpoint. Then you can tune the plate if needed. [edit removed] Again, as a dynamic system, if you get it close to spec, don't overdo the adjustments.

 

Hi,
I did a test of my AAV at 20°C by putting 12V to the bimetallic strip. There is only movement the first 3 min, then it stays with a square notch opening :

start heating bimetal

after 2 min

after 4 min

after 6 min

after 14 min


When driving the car, the AAV will close completely due to heat of engine.
But I suspect it closes too soon when engine is warming up….so I need to make the AAV more open by bending the strip a bit, correct?
I only get 1000 rpm with cold start. Shouldn’t this be 1200 rpm. Setting the idle at 1200 rpm with cold engine has no sense, because this would also
set the idle higher once engine is warm.
Now, the warm engine has an idle of about 800 rpm. So this means warm setting is ok, but cold not.