AAR How open is open??

[stutt66]

I'd like to restate my questions for other who have the same issue. I'm trying to improve my cold start on a 1976 turbo. I'm checking my AAR and wanted to know how open the air passage should be when engine is cold. Please let me know what you think..

[mark houghton]

Your first two pictures show it open more than it needs to be stone cold...looks like about 3/4 open. That should have resulted in a fairly high idle. From my experience, only the horizontal section (and maybe a bit more) of the opening is visible when cold. I would say that mine is about 1/4 of the total opening surface area showing when cold. Each car is different, and of course it also depends on where your idle adjustment screw it set at to some extent.

A couple things about these AAR's: You can bench test (well, actually fridge and oven test) the function of these to see if the disc inside is rotating and opening/closing as it should. Throw it in the fridge for awhile and note that it should be almost completed closed off. Throw it in the oven (150) for awhile and see that it opens up. At least you'll know that it's mechanically functioning. The other thing is to put a VOM across the electrical connections to look for continuity and resistance. I don't remember exactly, but you should be seeing probably 30 ohms resistance or in that neighborhood. If it's showing an open circuit, then the internal heating element is toast and the thing will keep your car at perpetual high idle 'cause it won't heat up enough to close off. Finally, you need to know that the AAR heating element draws it's power from the rear fuel pump circuit....as does the WUR.

You should put it on the car, check the degree of open when stone cold, then start and run the car until fully warmed up and pull the hose and check how far it's closed. If it isn't moving at all, either it's not getting power, the element is toast, or the thing is just plain gummed up.

[JFairman]

The bimetalic spring inside the AAR is held in position just like the bimetalic spring inside the control pressure regulator/WUR.
The static position of that spring is adjusted the same way in both of them. The steel interference pin they are mounted on is tapped into postion with a small hammer and brass drift punch or squeezed into place with a C-clamp and small socket used as a drift.
I've never adjusted my AAR because mine works perfectly but thats how it is done and you'll see the round steel pin if you look for it.

[mark houghton]

Originally Posted by JFairman

The bimetalic spring inside the AAR is held in position just like the bimetalic spring inside the control pressure regulator/WUR.
The static position of that spring is adjusted the same way in both of them. The steel interference pin they are mounted on is tapped into postion with a small hammer and brass drift punch or squeezed into place with a C-clamp and small socket used as a drift.
I've never adjusted my AAR because mine works perfectly but thats how it is done and you'll see the round steel pin if you look for it.

Yep, can be done. I adjusted mine slightly early on, to get my cold idle up a bit. Haven't touched it since.

[stutt66]

Pictures of 2 AAR I have.

[gsxrken]

Here's my one just out from the freezer:


And the same one just out of the over:

[stutt66]

Ok thanks for sharing... those are good pictures...What about the electrical element? Is Mark correct with the resistance about 30 omhs?