I have a 1970 Dodge Dart Custom 4-Door with a 225.
So, according to the book I have (the Haynes '67-'76 repair manual for Darts and Valiants of the Slant Six type), my air cleaner is a "temperature controlled" model. Now, I'm pretty sure, although I'm going to check tomorrow so I can be 100%, that it's not doing whatever it's supposed to do.
My question is, what is the significance of it's intended function? Is it bad for it to not work? Should I see about fixing it, and would it be an easy fix?
Thanks in advance!
-Casey

Frank?

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If it ain't broke, fix it!

I opened up my Haynes repair manual for 71 thru 89 models (#30050) and found a description of it on page 6-27. The section goes as follows:

1. The heated inlet air system is to keep the air entering the carburetor at a constant temperature. The carburetor can then be calibrated much leaner for emissions reductions, faster warm up, and improved driveability.

2. Two air flow circuits are used. They are controlled by various carburetor vacuum and temperature sensing valves. A vacuum diaphragm operates an air control valve in the air cleaner snorkel. When the underhood temperature is cold, air is drawn through the shroud which fits over the exhaust manifold, up through the air pipe, and into the air cleaner. On dual-snorkel air cleaners, both air control valves open during hard acceleration (when manifold vacuum drops below 5 inches).

3. As the underhood temperature rises, the air control valve will be closed by vacuum diaphragm and the air will be drawn through the cold air snorkel or duct.


This thing just warms up the air so fuel evaporates more easily. It also helps minimize carburetor icing. If you live in Georgia, the valve would probably be open all the time. So if you have it, it wouldn't hurt to keep it in working order. There isn't much to it so it shouldn't take too much to fix it if it's not working. If it's not working and you don't want to fix it, just plug its vacuum supply and the valve will stay open.

It's easy to check if its working and follow the directions in your manual. It doesn't hurt performance and helps your car run better so I would try to keep it in working order.

Frank

Yeah, my car does seem to have trouble warming up... and I live in california, so it's not actually cold.

Frank, if you reference the pics of my "super-duper six" Duster in the slixer's gallery, you will see that I have actually constructed a dual snorkel "ram-air" system which employs carb heat as a secondary feature... With those headers, of course, almost NO heat gets to the intake in those few cold months we have here, plus ice cold outside air would be rushing in the scoops if it were a "full-time" system. Therefore I have the snorkel blocker doors hooked to the thermostat inside the air cleaner housing (which I might add, for the benefit of all, is adjustable) just like a stock dual snorkel a/c. This supplies necessary carb heat in winter/cooler days to keep the carb from icing (which does happen without it) among other things.

Before you suggest that I add hot water to the manifold, please note that I am extremely happy with the setup as I now have it for my purposes/climate.

D/W

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If it ain't broke, fix it!

I was admiring the nice job you did with the installation several weeks ago. It's a work of art!

Frank

Thank you.

D/W

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If it ain't broke, fix it!