Valve Overlap Specification Methods
#1
FormerVendor
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Valve Overlap Specification Methods
Hi ALL, I would like to state the Valve Overlap Amount Specification I use for quality engine performance.
I invite other methods to be shared, to help LS-1 tech Members.
I often fit a camshaft of 180/188 .525" on a 102 C/L
This engine operates at WOT for 25K hours.
MY Overlap specification is based on time spent at PTO vs WOT under the Mode of engine operation.
THUS at PTO there is a LOW overlap requirement. (low port air density)
The fact that runner lengths MUST also match is a major consideration.
The Exhaust Pressure (E-MAP) is a great concern for correct spectfication.
Other Thoughts ?
Lance
I invite other methods to be shared, to help LS-1 tech Members.
I often fit a camshaft of 180/188 .525" on a 102 C/L
This engine operates at WOT for 25K hours.
MY Overlap specification is based on time spent at PTO vs WOT under the Mode of engine operation.
THUS at PTO there is a LOW overlap requirement. (low port air density)
The fact that runner lengths MUST also match is a major consideration.
The Exhaust Pressure (E-MAP) is a great concern for correct spectfication.
Other Thoughts ?
Lance
#2
TECH Senior Member
What is an engine operated as above used for? Stationary industrial comes to mind. 25K hrs is a LOOONG time! lol
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Originally Posted by G Atsma
Hi Lance! First, just to clarify, PTO = Part Throttle Opening ?
What is an engine operated as above used for? Stationary industrial comes to mind. 25K hrs is a LOOONG time! lol
What is an engine operated as above used for? Stationary industrial comes to mind. 25K hrs is a LOOONG time! lol
A cam like lance proposes makes a lot of sense in this application. These motors never exceed 2500 rpm or 20 mph.
#4
TECH Senior Member
I was thinking large stationary engines, but totally see it in a forklift! Long hours accelerating and decelerating, revving to lift, a super-mild cam would sure do it!
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1 Million Mile Engine
Hi ALL, yes this is a 1 million mile engine@40 MPH average.
True, the application is for CPS in Paris, Texas.
A Natural Gas pump, engine running on NG.
The engine is maintained, oil changes/filter changes WITHOUT ever being stopped !
This type of engine is fitted with my IGN-8 and ignition coils.
This engine's MAX RPM is 1800.
The Oil Pump is the first item to wear out.
To ALL, a good guess though the Overlap question requirement was not addressed ?
Lance
True, the application is for CPS in Paris, Texas.
A Natural Gas pump, engine running on NG.
The engine is maintained, oil changes/filter changes WITHOUT ever being stopped !
This type of engine is fitted with my IGN-8 and ignition coils.
This engine's MAX RPM is 1800.
The Oil Pump is the first item to wear out.
To ALL, a good guess though the Overlap question requirement was not addressed ?
Lance
#7
TECH Senior Member
Lance hasn't posted here since August of last year, and is no longer a sponsor.
You might try to contact him at his business-
Pantera EFI
1-949-250-1797
You might try to contact him at his business-
Pantera EFI
1-949-250-1797
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G Atsma (07-28-2020)
#10
It's a shame he's off the forum now, the guy had a lot of really interesting insight.
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G Atsma (08-17-2020)
#11
TECH Senior Member
Yeah, I got the feeling PanteraEFI is a side operation, just the tip of Lance's iceberg.
I think his fingers extend to many different pies...
I think his fingers extend to many different pies...
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G Atsma (08-21-2020)
#13
TECH Senior Member
#14
9 Second Club
Definitely a very smart man, although sometimes I think he talks in riddles ! Can be hard to understand sometimes.
But in terms of skills and abilities, he's well into top racecar territory.
But in terms of skills and abilities, he's well into top racecar territory.
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G Atsma (08-21-2020)
#15
TECH Senior Member
Just my little theory....