Engine Valves

[thisoldtruck]

Hi,

 

I'm looking at rebuilding my 251 in my truck.  At the very least, I'm sure I'll need a valve and ring job.  But I've wondered if sodium valves hold up to today's gasoline at all or if a 214N alloy valve would be the better way to go?

 

Any thoughts?

 

Thanks,

Andy

[Dodgeb4ya]

I have sodium valves in my 265 PU....never an issue for many years.

I have them in a couple other trucks too..heavy duty service.

The only way to go regardless of todays fuel IMO.

[thisoldtruck]

Thanks Dodgeb4ya,  that's what I'm thinking of doing. But wanted to be sure the sodium valves will hold up ok, they should as they cool better.

 

Thanks,

Andy

[Jomani]

If I recall correctly, the big concern with the switch to unleaded gas was the valve seats and not the valves themselves. As it turns out, unleaded gas seems to work better in older engines because it reduces the amount of carbon buildup. The bigger problem is the ethanol that they are adding to gas. It tends to be more corrosive and holds more moisture than plain old gas. Back in the 70’s when ethanol was first introduced, I was working at a gas station in Minnesota. After we started selling ethanol, I spent the next six months pulling and flushing gas tanks - it tends to dislove all of the scale in the tank and plugs up everything in the fuel system.

 

As you said, sodium filled valves cool better. Most burnt valves are caused by running too lean of a fuel mixture. The faster the heat gets transferred away from the combustion chamber the better.

[kencombs]

k

It looks like ethanol has been offered for a lot longer than I thought!  At least judging from the cars, pumps and clothes! late 30's?

 

Anyway, you're right about valves and seats.  The sodium valves do transfer heat from the valve head to guide much better than a normal valve.  And, our flatties have hardened seats from the factory, so we're good.

[Veemoney]

The heat transfer benefits of sodium valves used on our flatheads is IMO the best way to go for our low rev motors used on the street if that is the way they are set-up. Just some FYI below.

 

Some Chrysler hemi motors came with sodium exhaust valves. The sodium valves have a larger diameter stem and require a larger diameter valve guide and weigh more. For those power hungry builds on the hemi motors reducing the weight of the valve helps reduce valve float at high rpms. Reducing the  diameters of the components projecting into the ports increases head flow.

 

   

[Dodgeb4ya]

The Dodge truck Hemi's and some of the 30" Moly Block engines use valve rotators with sodium valves for even better valve and seat life for severe service..

None of this is for those who feel the need to reach the valve float pinacle.