Category: Fact & Fiction

 

We cannot thank you enough for the engine, and for your interest to help support St. Jude Hospital.

St Jude Cobra

 

 

 

 

 

 

 

JD Peeples

Director – Sports Marketing

ALSAC St. Jude Children’s Research Hospital 

 

 

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Effect Of Changes In Cam Timing And Lobe Separation Angle

The following tables illustrate how variations in lobe separation angle and cam
timing will effect the behavior of the engine in which the camshaft is installed.
EFFECTS OF ALTERING CAMSHAFT TIMING
Advancing Retarding
Begins Intake Event Sooner Delays Intake Closing Event
Open Intake Valve Sooner Keeps Intake Valve Open Later
Builds More Low-End Torque Builds More High-RPM Power
Decrease Piston-Intake Valve Clearance Increase Piston-Intake Valve Clearance
Increase Piston-Exhaust Valve Clearance Decrease Piston-Exhaust Valve Clearance
EFFECTS OF CHANGING LOBE SEPERATION ANGLE (LSA)
Tighten (smaller LSA number) Widen (larger LSA number)
Moves Torque to Lower RPM Raise Torque to Higher RPM
Increases Maximum Torque Reduces Maximum Torque
Narrow Power band Broadens Power Band
Builds Higher Cylinder Pressure Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock Decrease Chance of Engine Knock
Increase Cranking Compression Decrease Cranking Compression
Increase Effective Compression Decrease Effective Compression
Idle Vacuum is Reduced Idle Vacuum is Increased
Idle Quality Suffers Idle Quality Improves
Open Valve-Overlap Increases Open Valve-Overlap Decreases
Closed Valve-Overlap Increases Closed Valve-Overlap Decreases
Natural EGR Effect Increases Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance Increases Piston-to-Valve Clearance
CAMSHAFT GEOGRAPHY AND LOBE FUNCTION
1) Max Lift or Nose Lobe Separation Diagram
2) Flank
3) Opening Clearance Ramp
4) Closing Clearance Ramp
5) Base Circle
6) Exhaust Opening Timing Figure
7) Exhaust Closing Timing Figure
8) Intake Opening Timing Figure
9) Intake Closing Timing Figure
10) Intake to Exhaust Lobe Separation

 

Effects Of Changes In Cam Timing And Lobe Separation Angle

The following tables illustrate how variations in lobe separation angle and cam
timing will effect the behavior of the engine in which the camshaft is installed.
EFFECTS OF ALTERING CAMSHAFT TIMING
Advancing Retarding
Begins Intake Event Sooner Delays Intake Closing Event
Open Intake Valve Sooner Keeps Intake Valve Open Later
Builds More Low-End Torque Builds More High-RPM Power
Decrease Piston-Intake Valve Clearance Increase Piston-Intake Valve Clearance
Increase Piston-Exhaust Valve Clearance Decrease Piston-Exhaust Valve Clearance
EFFECTS OF CHANGING LOBE SEPERATION ANGLE (LSA)
Tighten (smaller LSA number) Widen (larger LSA number)
Moves Torque to Lower RPM Raise Torque to Higher RPM
Increases Maximum Torque Reduces Maximum Torque
Narrow Power band Broadens Power Band
Builds Higher Cylinder Pressure Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock Decrease Chance of Engine Knock
Increase Cranking Compression Decrease Cranking Compression
Increase Effective Compression Decrease Effective Compression
Idle Vacuum is Reduced Idle Vacuum is Increased
Idle Quality Suffers Idle Quality Improves
Open Valve-Overlap Increases Open Valve-Overlap Decreases
Closed Valve-Overlap Increases Closed Valve-Overlap Decreases
Natural EGR Effect Increases Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance Increases Piston-to-Valve Clearance
CAMSHAFT GEOGRAPHY AND LOBE FUNCTION
1) Max Lift or Nose Lobe Separation Diagram
2) Flank
3) Opening Clearance Ramp
4) Closing Clearance Ramp
5) Base Circle
6) Exhaust Opening Timing Figure
7) Exhaust Closing Timing Figure
8) Intake Opening Timing Figure
9) Intake Closing Timing Figure
10) Intake to Exhaust Lobe Separation

 
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Hey guys, we got the engine in this weekend. It went pretty smoothly other than we took the cap off the End of the transmission by spline and as we tipped the unit down upon lifting it a bunch of the transmission fluid leaked out. We put that cap back on and it was fine. We will refill the transmission fluid.

Thanks for all the help getting to this point.

 427w EFI

Stuart K

48