Just picked up the march edition of diesel power, got lookin through the project rust bucket pages, it says they had the head shipped out to be O-ringed... stupid question but what does that mean and how is it done?

 

An image search may help you better than any text explanation. Hit up Google image search.

 

The head (and or sometimes the block) get a groove machined around each cylinder. A wire (usually copper) is put in the groove, then when the heads are torqued on the wire gets smashed and makes a very positive seal. This is generally recommended on our truck at pressures about 40 psi.

 

To expound on what Mark said:

O-rings do not necessarily get smashed, rather it gives an additional pinch point to the headgaskets fire ring, or the metal part that goes around each cylinder. Copper and stainless steel are 2 popular ones.

Fire-ringing is the process of of cutting a groove in the block like an O-ring setup. 2 pinch points mean even more holding pressure. However, these sometimes loosen up and are used mostly for competition who take the head off frequently.

 

When we used to use copper o-rings with steel shim head gaskets they would deform. But I can't imagine a stainless one deforming much.

 

mine is stainless .052 i believe and it sits just on the metal "rim" that surrounds the cylinder.

 

That's more of a "Fire ring".

 

but a fire ring uses a special gasket with that "metal lip removed"
like this.




a oring like i stated uses a factory gasket . mine is not like a fire ring.

its .51 wire and after the deck iam at .012 petrusion

 

Here's two pictures of what they look like, one on a 12 valve head, the other on a 24 valve head.




This is how I cut them in, a groove is cut so that it is centered on the stock fire ring. The width and depth depend on the diameter of the wire used, I use .050" wire and aim for a .010" to .012" protrusion.