Brainstorming...

L

LReiff

The Antistock
Joined
Apr 8, 2009
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On the 5.9 cummins there is a dead air space inside the fire ring of the head gasket (the ID of the fire ring is larger than the cylinder bore) between the head and the block. In my way of thinking this space will hold exhaust gasses that later mix with the clean intake air during the compression stroke causing a less than desirable combustion environment.
 
Not enough to worry about. Compare that to the effects of drive pressure.
 
Hmmm... Residual gas. I believe that is why engineers have tried to control the air movement or "swirl" inside the cylinder/bowl.
 
You will see the same effect with different grind cams as well. Lobe timing and overlap. Dont sweat it.
 
Snedge said:
Hmmm... Residual gas. I believe that is why engineers have tried to control the air movement or "swirl" inside the cylinder/bowl.
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Yep...residual gases are a key to the control of emissions. Most of the concern is with the gases trapped just above the first piston ring though - similar case to what Lee mentioned, but design engineers aren't worried about fire-rings at the factory LOL
 
There is a way to eliminate this dead air space, I just wondered if anyone had fooled around with it or had experience either way, even if it was in a different application.
 
j-rod said:
Yep...residual gases are a key to the control of emissions. Most of the concern is with the gases trapped just above the first piston ring though - similar case to what Lee mentioned, but design engineers aren't worried about fire-rings at the factory LOL
Click to expand...

I think Lee was talking about the fire ring as in, the head gaskets own fire ring. Not the machined type.

LReiff said:
There is a way to eliminate this dead air space, I just wondered if anyone had fooled around with it or had experience either way, even if it was in a different application.
Click to expand...


JB weld?
 
I wish it was as simple as jb weld! I think there is power to be gained but not sure how much and if the amount gained will make it feasible.
 
Maybe its just me but I would estimate that the volume of "dirty" air contained in the piston bowl would dwarf the air in that dead space. :pop:
 
There may be another benefit to this, the head gasket fire ring would be shielded from extreme temperatures.
 
If this area is removed more material can be removed from the piston (referring to cut pistons) to unshroud the valves without lowering compression below what's desired.
 
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