Technical '56 truck hemi - sodium-filled valves

A few years ago, I bought a 331 Chrysler "Power Giant" out of a '56 Dodge dump truck. The guy I bought it from said it had just been rebuilt and then the clutch went out; they then decided to cut their losses and put it up for sale. I bought it and mounted it on my test stand, and as far as I could see, it is probably a fresh rebuild. I ran it a number of times, once as long as 20 minutes. It carried 55 lbs of oil pressure hot, and never ran over 175 degrees. In short it performed just like a fresh engine.

I would like to use this in a "T" tub project I have going. I already have a car timing cover and a "wet" 4BBL manifold to use, but I am concerned about the possibility of valve problems.. I have heard that the trucks had sodium filled exhaust valves that are very heavy. I know nothing about this and would like to see some opinions on whether this engine would be suitable to be used "as is". It seemed to want to rev to around 4000 RPM easily (I never tried to see what the max revs would be). I would think that if I kept it below 4000, I would have no problem. It should have a ton of torque and should be able to haul a 2000 lb car around with great alacrity, and should be more rugged than a similar car engine.

Anyone see a flaw in my logic?

Also is there any way to tell if it has the special exhaust valves? I could measure the diameter of the stem, which I would expect to be larger than standard exhaust valves, but is there any other way (short of disassembling the engine). Thanks for any help.

 

I believe the sodium filled valves would have been for irrigation/agriculture engines that ran on natural gas, propane ect. I have heard of truck engines with them. ie, industrial. Don't know how to tell them apart cept tear it down. Lippy

 

Porsche 914 engines had sodium filled valves.

 

Sodium valves on exhaust only.
Old air cooled tech.
Lots of industrial engines use them ( 4.3 vortecs, etc)
Conduct and dissipate heat very well
Good to use in high load , extended use engines, propane etc.

The valve stem will be notable thicker then a regular valve, but usually stepped down to use stick keepers and springs ( at least the heavy equipment engines I’ve torn down)

Use it as it is, they are fine.

 

Denny, the Hemi truck engines did use sodium filled exhaust valves. They have 7/16” valve stem diameter as I recall so should be easily verified by removing a valve cover, if knowing for sure is important to you. In my opinion, their is no reason to be concerned about them being there. They are simply a ‘heavy duty’ valve component.

That said, when I had a set of 315 Power Giant heads rebuilt for passenger car use, I had the guides and valve replaced with the standard size car components. However, that engine was in need of an overhaul, not already a fresh rebuild.

 

Thanks, guys. I really don't see the need to tear down an engine that runs this good. The engine now has an odd-ball 2 BBL carburetor with a governor that cuts in around 4K. Perhaps a rev limiter is in order?

 

Military applications used sodium cooled valves. They come with safety issues.

IF SODIUM COOLED VALVES ARE CUT UP AND THEN ALLOWED TO COME INTO CONTACT WITH WATER, THERE IS A SERIOUS RISK THAT THE SODIUM WILL CATCH FIRE AND EXPLODE, CAUSING THE VALVE TO BE EJECTED WITH CONSIDERABLE FORCE ACROSS A ROOM

 

I personally would not worry about them as was mentioned. Just run it and don't worry. LOL. Lippy

 

Great fun at the machine shop … 4:30 comes, everybody grabs a beer & we break the heads off the sodium valves & throw 'em in the 20 foot long hot tank !

 

the only flaw in your plan is that the engine should be in my A coupe. Sodium gives off hydrogen when it comes into contact with water. And a little spark sometimes. Boom!

 

Leave them alone. They are not a concern, unless you are planning on running this at extreme revs.

If the idea of keeping them bothers you, you can have the guides replaced with ones that can accommodate a "regular" Hemi valve.

I would save the cash for the adapter that you are going to need to put a nice transmission behind it.

It will make a fine engine, albeit a bit heavy, for a T.

 

I have a 250 H.P. 331 Chrysler Marine motor. It has a decal on the valve covers stating " Equipped with sodium filled valves. Also solid lifters and 2x4 intake
assembly. I dont think a little higher rpm would be a
problem.

 

I already have the adapter. It took a while, but I found one a while ago. Right now, I have a '50 Ford transmission with overdrive; I'm still looking for a T85 or an early 4 speed. (This project was a no-go unless I found that adapter.)