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The heat riser valve on my '39 Six was rusted frozen in the 'weight down' position when I got the car. The spring is missing. I was able to free up the valve with rust penetraters and it flops up and down very freely now. My initial take was that the 'down' position was the valve being closed and that the spring would heat up and lift it open, then as it cooled off, the weight would pull it down. I subsequently wired it in the 'up' position so it wouldn't over heat and at some point posted same here on the site. Somebody said that was incorrect and I removed the wire. The guy helping me with the car now, thinks it should be wired up - can somebody give me a definitive answer???? The manual says the proper function of the valve is critical to the engine operation and I agree. I guess the other question would be 'does anybody know where I can find a spring??? I am guessing the way the spring would install would make the answer self explanatory. Thanks to any answers....

Assuming it is correctly assembled, the valve is open when the counterweight is down. As the bimetallic spring warms, it relaxes and allows the counterweight to overcome the spring tension and drop, thus opening the valve. When the spring cools, it overcomes the weight of the counterweight, lifting it up and closing the valve.

Springs for many of the heat riser valves are available from the normal Packard vendors.

Thanks Dave,

I will email M.M.

Chris

Hi Chris,

I have a spare one - NOS
PM for details

Brian

I just replaced the exhaust manifold gasket with one of the Packard designed metal flange ones. I had both intake and exhaust manifolds sandblasted and refinished in the raw cast iron color from Hirsch. My heat riser was in great shape so when I reinstalled it, I had to lubricate it. As I have a turbo diesel in my stable, I withdrew some diesel fuel (which is basically kerosene) and mixed with graphite powder you can get in a hardware store for lubricating locks.

I put the mixture in one of those squeeze bottles with the pointed nozzle you often see in restaurants. So, it was easy to lube it and after it is on the car, I will still be able to shoot some lube into it when needed.
Just FYI.

Thanks for posting this information. I got curious about the heat riser on my 23 series. Found out the spring was missing and a very different riser than is listed in '48-'54, Plate No. 92-Group 5.0908 Parts Detail.
Any ideas? Is the riser on my Packard (see pics) correct?
Again thanks for the help.

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it is the same as in the parts book but it is missing the thermostatic spring. from the looks of the "thing" near the weight I think the shaft is frozen, quite common.. Liberally use penetrating oil of your choice or PB Blaster, tap lightly in all directions, repeat, repeat, repeat etc