Packard Forum Index » Pre-War (1899-1942)

If I interpret what's been said correctly, you've wired the heat riser valve in the wrong position. You want the counterweight DOWN so the valve is open. That may or may not be the source of your problem, but its the place to start.

Re the counterweight - I PRESMUED that the counterweight would pull the valve closed and the helix spring would expand with heat and open it. Am I backwards here?!?!?

The HRV was frozen with the counterweight down and the exhaust was getting really hot really quickly, and in researching online, this was mentioned as a possible reason. I got it freed up and then wired it with the counterweight up. If this is wrong, it is as easy as snipping the wire to let the counterweight go back to the down position, but the problem existed and was unchanged with either scenario. Is counterweight down definitely the 'open' position???

The bimetallic coil spring keeps the valve closed initially and as the spring heats it relaxes the tension on the shaft, allowing the counterweight to drop and gradually open the valve.

Packard Newbie,
Sounds like you might be missing the bimetal spring and cover. My car was. The helical spring is an anti-rattle spring. Do a site search here and you will find several discussions and illustrations.
Mark