Cascade Overflow Valve
- Thread starter Vrabel
- Start date
I have no info for you Chris , but I would call Wicked diesel and see if Shane has any info , or see what he would charge to fix it for you , maybe even a little more flow while he is in there
Moved to a better area for ya too .
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spoke to him. he told me what to look for. said LBZ's cheaped out and used a weaker spring. gonna yank it as soon as I can pull it inside.
I dont know either but my guess would to regulate what fuel is sent through the return line .
DESCRIPTION
The COV is located on the front cover of the high pressure pump.
The Cascade Overflow Valve has three functions:
- regulation of lubrication fuel to the internal moving parts of the high-pressure pump
- regulation of the fuel pressure being supplied to the Fuel Control Actuator solenoid valve
- return excess fuel to the fuel tank
This regulated internal pressure is known as housing pressure, and is determined by engine displacement and power requirements
OPERATION
The COV has a spring-loaded center spool-piece that has a drilled channel with three passages: one for initial low-pressure lubrication, one for lubrication at housing-pressure , and one for overflow. The valve is operated in three stages based on the level of pressure at the inlet.
Stage 1
When the fuel pressure entering the tip of the COV is between 0 and 3 bar (43psi), pressure is too low to overcome regulator spring tension and fuel flows through the center channel, only . This passage always allows fuel flow through to the pump center-ring and lubricates the pump bushings and internal moving parts. This circuit also allows air to bleed during initial cranking and returns the air to the fuel tank.
The COV is in Stage 1 during cranking, only.
Stage 2
When the fuel entering the COV exceeds 5bar (80psi), but is less than 12.4bar (180psi), the spool-piece moves against spring tension aligning a second passage for lubrication purposes.
Stage 2 can be reached during cranking and initial start up.
Stage 3
When fuel pressure exceeds 12.4bar (180psi), the spool-piece aligns with the overflow passage. This stage relieves the pressure into an overflow circuit that sends the fuel back to the inlet side of the gearotor pump, thus limiting maximum fuel pressure to 12.4bar (180psi).
Lubrication fuel continues to flow through all channeled passages during this stage.
Excess fuel is sent back to the fuel tank through the fuel-return circuit
Stage 3 is reached at over-pressure
The COV is located on the front cover of the high pressure pump.
The Cascade Overflow Valve has three functions:
- regulation of lubrication fuel to the internal moving parts of the high-pressure pump
- regulation of the fuel pressure being supplied to the Fuel Control Actuator solenoid valve
- return excess fuel to the fuel tank
This regulated internal pressure is known as housing pressure, and is determined by engine displacement and power requirements
OPERATION
The COV has a spring-loaded center spool-piece that has a drilled channel with three passages: one for initial low-pressure lubrication, one for lubrication at housing-pressure , and one for overflow. The valve is operated in three stages based on the level of pressure at the inlet.
Stage 1
When the fuel pressure entering the tip of the COV is between 0 and 3 bar (43psi), pressure is too low to overcome regulator spring tension and fuel flows through the center channel, only . This passage always allows fuel flow through to the pump center-ring and lubricates the pump bushings and internal moving parts. This circuit also allows air to bleed during initial cranking and returns the air to the fuel tank.
The COV is in Stage 1 during cranking, only.
Stage 2
When the fuel entering the COV exceeds 5bar (80psi), but is less than 12.4bar (180psi), the spool-piece moves against spring tension aligning a second passage for lubrication purposes.
Stage 2 can be reached during cranking and initial start up.
Stage 3
When fuel pressure exceeds 12.4bar (180psi), the spool-piece aligns with the overflow passage. This stage relieves the pressure into an overflow circuit that sends the fuel back to the inlet side of the gearotor pump, thus limiting maximum fuel pressure to 12.4bar (180psi).
Lubrication fuel continues to flow through all channeled passages during this stage.
Excess fuel is sent back to the fuel tank through the fuel-return circuit
Stage 3 is reached at over-pressure
yea up until yesterday I didnt know that this little gem was in there. now to see if we can check it and service it if needed.
What kind of problem are you having? We usually don't see any issues with the cascade overflow valve on the pumps we service. It would have to have had some serious contamination to be bad but honestly other parts would fail before the valve would go bad.
Spencer
Spencer
truck wont start appeared to not be building pressure. made about 1000 psi but that was a struggle. we have done some testing whuch I will post in the other thread in a minute. http://208.109.104.11/forum/showthread.php?t=19263
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So does this mean someone could use a cascade valve from a Cummins truck and get more case pressure? Here is a part # F00N202231
why are you wanting more case pressure? its a 13 year old thread and Vrabel hasnt been on in 5 years
I'm just trying to experiment with higher case pressure. If it truly is a higher spring rate it should help the efficiency of the cp3 especially if the one in my 16yo lbz is weak so I wanted to experiment with it.
Might work but it would be more of a temp
bandaid on a worn pump. More lift pump pressure would help as well
bandaid on a worn pump. More lift pump pressure would help as well
I don't necessarily think my pump is worn. I just want to experiment with the cascade valve being that someone said gm cheaped out and used a spring with a lesser rate. Motorsport diesel put a video on YouTube showing the difference in efficiency with just replacing the cascade valve so if this is true it couldn't hurt to get a little more flow out of the pump to help keep up with some worn injector ball seats too.