L134 Exhaust Valves - Rotating or not?

[Misdemeanor]

I'm a confused on the types of valves used in the L134. I am in the process of rebuilding my M38 and have torn it down and had the block machined. Hardened valve seats are installed. I purchased new valves and the intake appear to be a direct replacement. However, the exhaust valves originally installed appear to be the rotating type. The new ones??

The question is should I use the new valve and get the correct retainers or do I have the wrong valves? I'm hoping someone can explain the whole rotating vs non-rotation valve thing and what is the standard practice when rebuilding.

The valve on the left is the new exhaust and the center is the old exhaust and the far right is the old intake. The new and old intake are the same.

 

[ShearerLegal]

The purpose of rotating exhaust valves is so that the same part of the exhaust valve is not constantly exposed to the hot exhaust leaving the cylinder after combustion. It is considered a performance upgrade in a flat head style engine. Unlike an overhead valve engine, the exhaust goes down the side, so to speak, at a 90 degree angle instead of around the valve head and towards the stem of the valve. Rotating the exhaust valve cuts down on burnt exhaust valves because the same part of the valve head is not exposed to the highest heat of combustion at every firing event. A non-rotating exhaust valve will work, but a rotating exhaust is better. If it were me. I would go back with the rotating exhaust valves.

 

[Misdemeanor]

That makes sense. I think I want to keep the rotating style. My caps appear to be in good condition.

Can I use the new exhaust valve with a different type of retainer. It looks like the new valve has the same retainer as the new and old intake. I am trying to figure out if the rotating valve is unique or if the new valve is okay to use with the rotating cap. I don't see why not but the old one is different.

 

[ShearerLegal]

Usually the rotator style exhaust valve comes with a different and unique style retainer. The exhaust is machined to fit the rotating style retainer. I don't think your new valve will work unless you use it as a non-rotating valve.

 

[Misdemeanor]

your right.The valve on the left is the new valve and uses a different type of retainer. Anybody know where I can but a new rotating type exhaust valve?

 

[Jeepsinker]

Rotating valves are supposed to keep carbon fouling down as well.

 

[Misdemeanor]

After some research I think the Exhaust valve is from a later model F head. Mine if the L head. I assume this was the practice during the rebuild process to "upgrade" the L head non rotating valve with the F head valve and a rotating cap. Can someone confirm this and point me in the right direction for documentation?