H D truck engine sodium valves.

[40 Deluxe]

Originally Posted by wellcraft17

If there is always pressure being present in the exhaust port how is oil consumption a factor from the exhaust valve and guide? I understand the intake as you have a vacuum that can pull oil into the cylinder due to a bad seal and or guide. I’m not arguing with anyone’s opinion just trying to find out why exhaust valves have seals.

There may not always be pressure in the exhaust port. When the exhaust vale opens, a pulse of hot high pressure exhaust gas moves through the port into the manifold, followed naturally by a pulse of negative pressure. While all 8 cylinders combined will create positive back pressure in the downstream exhaust system, right at the port there will be constant cycling of positive then negative pressure.

[reddog565]

Hey guys, this is what I found out. The stem diameter of a sodium valve is 0.4 3 4 5. Egge machine has valve stem seals for this! So when I get them on I'll let you guys know..Love the barn....

[reddog565]

Sorry for the last sentence . Meant to say ,I'll let you guys know if it cured my problem.

[KULTULZ]

While early AM Carousing With My Browser ...

This is from the other forum-

Contrary to popular belief, the sodium filled exhaust valves did come from the factory with umbrella seals installed. Not running any seals on the exhausts in the long term will slowly create a build up on the valve undersides and eventually create other issues. I don’t stock those particular seals simply due to not restoring those heads with the original large stemmed valves in them. A shop that works on truck engines should have some of those seals floating loose. You could also try slipping some 3/8” stemmed umbrella seals over your current valves in lieu of finding the 7/16" seals and see if that works for the short term.

And here’s the reasoning behind why not to use those 7/16” stemmed valves in a street engine. In the truck engines, sodium filled exhaust valves have a life expectancy of ten years as the sodium does corrode or eat away at the interior of the valve stem and makes the valve prone to coming apart. It’s obviously not a good thing for an exhaust valve head to be bouncing around on top of moving piston. For what you are doing, a good cylinder head man would have simply recommended installing a new set of 11/32” guides and the appropriate new valves for the exhausts to get rid of the sodium filled exhaust valves.

TED EATON

SOURCE- http://forums.y-blocksforever.com/Topic146422-2.aspx

He's the man and has the final say.

Why the seals are not listed in the MPC I have no idea. But this info may be useful to someone one day.

In addition and IMO ... ..., the heads were designed and intended for low RPM usage. They have smaller valves and are not power producers.

[KULTULZ]

- ADDENDUM -

OK, Mr. Eaton says there are seals on the HD Engine sodium filled EXH valves. As usual, I begin wondering (as I do when staring at a lit match), there has to be something else going on here.

So I pull out my SHOP MANUALS (1955 and 1957 - I have no 1956) and begin to cipher.

- FYB 256-172-292 HD -

1955 239/256 CI –

Rotating-type intake and exhaust valves are used in the 239 cubic inch EBV and EBW engines. The 256 cubic inch EBZ engine uses rotating-type intake valves and free turning exhaust valves. The 239 cubic inch engine incorporates umbrella-type valve seals in both valve assemblies, while the 256 cubic inch incorporates them in only the intake valve assemblies.

Source - 1954-1955 FORD TRUCK SHOP MANUAL

1957 272 CI

Rotating-type intake and exhaust valves are used in the ECW-Y cubic inch engine. The exhaust valve of the ECR 272, 302 and 332 engines are sodium cooled free-turning type, while the intake valves are the rotating type.

Source- 1957 FORD TRUCK SHOP MANUAL

EDIT -

The 1957 SHOP MANUAL shows the EXH VLV seal in the ILL of the EXH VLV ASSY

So, my contention is that FORD did not use EXH valve seals on the sodium filled valves until the 1957 model run.

This is in no way to contradict Mr. Eaton. It explains why one year doesn't have them and another year has.

The seals sourced from EGGE (excellent supplier BTW) must be for a 1957 HD engine and/or earlier retro-fit.

[darrell]

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ive taken apart more of these heads over the years and never saw a seal.his problems go deeper.

[KULTULZ]

Just realized ... ... why I couldn't find the EXH VLV seals in the MPC, the one I was looking through (1948-1956) only goes to 1956. The seals started in 1957.

Getting harder to find good help ...

[reddog565]

Final thoughts for a while... I guess I should have checked with the barn before I had these heads rebuilt. I certainly would have done away with the sodium valve and probably would have taken it to a more old car machine shop...that's why the barn is so helpful, could have saved me a lot of aggravation.... Thanks to all you guys for your replies.

[darrell]

most if not all these heads i had were rebuilt maybe the factory did put them on the rebuilders sure didnt.as i said i ran one of these in a car without a problem.

[KULTULZ]

OK ... follow up ...

In the 1954-55 FORD TRUCK SHOP MANUAL, PG 16, Table 1 will give what TRUCK ENGINES received EXH VLV seals.

The 256 w/ sodium filled exhaust valves did not have seals.

There are many differences between PASS CAR, TRUCK L/D and H/D FYB engines, all for a reason.

I would show the chart but my scanner is still on the fritz.

BASIC PN 6571 valve seal chart shown below -

[51504bat]

One thing to consider, Sodium is also highly reactive and will react violently with water. Kaboom!

[KULTULZ]

Also, the sodium fill is very corrosive possibly leading to a valve failure.

Below is a TABLE from the 1956 FORD TRUCK SHOP MANUAL showing on what engine EXH VLV seals were and were not used -

[rotorwrench]

Aircraft engines have been running them for a very long time on the exhausts. Oil and air cool these engines so they need good heat transfer to the valve guides. They use high chrome guides now days so that they will last an overhaul period. They do pretty well with the late guides. I've only seen one valve fail in the last 40 years and it was an intake valve. The reason it failed was that that particular engine had a loose fuel injector that was making it run lean with power. I ended up with it after a customer purchased the aircraft on one of those "Good Deal" purchases. It failed within 50-hours after he purchased it. I didn't get a chance to inspect it before he started flying it. So much for Good Deals.

We still inspect the exhaust valve guides every 300-hours on these engines but I think they could go a lot longer now than before they changed to the hardened steel valve guides.