I have a 1966 Cutlass Sports Coupe 330 4 barrel high compression engine with AC.
I need to replace the Vacuum Actuator for the fresh air door. It has only one vacuum port. I can’t seem to find the correct one. I don’t want to go used because of the dry rotted diaphragm thing. One of the big Olds parts places show two vacuum ports for my year Cutlass.

I also wanted to replace my vacuum advance on the OEM distributor.

If I actuate the mechanisms on both and hold my finger on the vacuum port, the mechanisms don’t hold what so ever. I can only assume the diaphragms are shot.

Thanks for your advice as always…

 

I don't know about the '66 specifically, but it's generally very difficult to find correct actuators. You generally have to find something that's close enough and then modify it. A two port should be able to be used in place of a single port.
The distributor advance is easier. All the GM advance units for points distributors mount and work identically. The stroke distance and vacuum levels vary (just like springs and weights vary), so you can get an aftermarket tunable one or shop around for one that appears to be similar to the original. I don't think the differences are all that dramatic so I wouldn't spend too much time on it. Note that even when good these modules will bounce back at least half way when testing by just compressing and covering the port - the spring is pretty strong!

 

Thanks Mr. Oddball. I can be such a dope. My AC actuator actually did have 2 vacuum nipples. Those vacuum actuators are available. It is just that one of the hose nipples was cleanly cracked off. I used a magnifying glass to see the slightly different color plastic where it was severed. Thanks for replying. Good to know that the distributor vacuum advance actuators are all pretty standard for GM of that era.

 

Something to learn and remember: A-body Chevrolets and Pontiacs use a lot of the same components the Oldsmobile A-bodies do. The amount of stuff reproduced for Chevelle and GTO is insane. We and the Buick guys benefit from that.

 

I believe the part you're looking for is called a "Mode Door Actuator" and I bought a new (repop'd) part from Old Air Products for my '72 442 convertible. The part number was 25-5901; I'm not certain the parts would cross match.

Rodney

 

Thanks to everyone who replied!