Quote:
Originally Posted by Stretch
Can you clarify if this happened at idle?
I only ask because "people say" (I will provide a reference in a bit honest!) that at low engine speeds the piston rings are not as effective as at high engine speeds => so they are meant to seal better at high revs; but because the engine is pumping a greater volume of air through itself at higher engine speeds blow by is more likely to be greater at high revs. This isn't the full story though because it doesn't include the effect of engine loading which can also induce greater blow by...
...after all that (deep breath!) what was happening to and within the engine when the measurement was made must be considered as well.
Have you had problems with the engine conking out under different conditions? Or have you just noticed this at idle.
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In My quote it has that I did it at Idle speed.
"
At idle speed I removed the Rubber Elbow from the top of the Valve Cover and covered and started counting 1000 one; 1000 two and so on until the Engine Shut Down.
It took 10 seconds for the Engine to shut down at an approximate pressure of 3.1 psig."
And, yes when the Engine is under a load the Cylinder Pressure is higher and that pushes the Rings more Firmly against the Cylinder Walls. Since the rings are pressed against the Cylinder harder that means when the Piston is going down the Top of the Piston Ring is also pressed harder against the upper Piston Ring Groove.
In fact on Loaded Big Rig Type Trucks if you get the Engine in the Wrong Gear and Lug the Engine badly lonh enough the Cylinder Pressure shoots up and you can start peeling/galling cylinder and Rings due to the increased the pressure pushing on the Rings.
Another issue is that blow-by has more time to get past the Rings (and Ring gaps) during idle.
I have had no issues with My own Engine dieing on Me so far.