Technical 1952 Nash Ambassador

I recently purchased a '52 Nash Ambassador and am having some difficulties in getting it road worthy. It is in good shape, body is a "survivor", straight 6 Jetfire engine runs good, but I have some little things I am up against.
1) I have a "miss" or "small jerk" when the car is running at about 45+ mph. I have cleaned the fuel tank, put 2 in-line filters in the gas line, cleaned the carburetor, replaced the points, spark plug wires, and plugs, but still can not come up with a resolution to this issue.
2) I have a water leak under the dash from the heater control valve. Do I need to replace the entire valve or are there O-rings that can be replaced?

 

Replace or rebuild the heater control valve.

 

1) sounds like a spark plug misfiring. Do any of the plug wires run parallel to each other and touch? They should be separated or cross at an angle or you can get crossfire. Could be a cracked distributor cap, weak points, or other ignition fault.

 

Check the coil. Could be marginal, especially that old.

 

The best source I've found for rebuilt Nash heater control valves and Nash parts is BlaserAuto.com in Moline Illinois. The company that made the kits has been bought out.
Your Jetfire 6 is an overhead valve. Check your rubber gas line hose between the fuel pump and the metal gas line. It's at the fuel pump. They sometimes crack with age and start sucking air causing jerking. Inside the distributor sometimes a wire will break inside the insulation where it flexes and will cause occasional misfire. You won't see it visually. Check the distributor shaft for play with the cap off. If there is some, it's worn. There's a lube screw on the outside, halfway down facing the engine. Hard to get to, but often neglected.
If your Nash is a survivor, an original or worn torque tube drive stabilizer can fail and cause some jerking or disable the car. www.NashRamblerRubber.com has the torque tube stabilizer trunnion for Rambler, Nash Ambassador, Hudson and Healey, and a description on the web page. You might pick up a spare since you can't find them in the auto parts stores and it makes for safe driving.
Don't forget to check and clean all the ground connections at and to the coil, distributor, and ignition circuit to insure maximum current for a good hot spark.