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AFTER I INTERVIEWED A CAMSHAFT REGRINDER ABOUT
HIS STATEMENTS THAT ALL OF HIS CAMSHAFTS WERE "COMPUTER DESIGNED", HE SAID
"HE ONLY COPIED COMPUTER DESIGNED CAMSHAFTS".
OK, NOW LET ME GIVE YOU MY "SECRETS OF GOOD COPY CAMSHAFTS"
NUMBER ONE, I RECOMMEND THAT
YOU START BY STRAIGHTENING THE CAMSHAFT ON CENTERS, NOT ON V BLOCKS. THIS
STRAIGHTENING ON CENTERS WILL DISCLOSE IF CUTTING NEW FRONT AND REAR CENTERS
IN THE CAMSHAFT IS REQUIRED. THIS PROCESS ALSO DISCLOSES IF A WIDE JOURNAL
HAS A "TWIST", WHICH REQUIRES THAT THE TWIST BE CORRECTED BEFORE FINAL
RE-CENTERING AND FINAL CORRECTING THE "RUNOUT". ALL THE JOURNALS SHOULD THEN
HAVE A "TOTAL" RUNOUT THAT IS LESS THAN FIVE TENTHS OF AN INCH (.0005" TIR).
TIR MEANS "TOTAL INDICATOR RUNOUT", OR PLUS AND MINUS .00025 TENTHS !
NUMBER TWO, USE YOUR BEST COMPUTER EQUIPPED CAMSHAFT MEASUREMENT MACHINE AND
MEASURE A MINIMUM OF FOUR INTAKE AND FOUR EXHAUST LOBES. MEASUREMENT OF ALL
THE LOBES ON THE CAMSHAFT IS A BETTER PLAN.
NUMBER THREE, PROCESS THESE COMPUTER GENERATED MEASUREMENT FILES WITH THE
PROGRAM PLOTVGA7.EXE AND REVIEW THE GRAPHS FOR BASECIRCLE "CONTOUR", FOR
TOTAL RUNOUT AND "WAVES". ALSO REVIEW THESE GRAPHS FOR THE BEST VELOCITY AND
ACCELERATION "SMOOTHNESS". NOW PROCESS THE BEST THREE OR FOUR INTAKE AND
THREE OR FOUR EXHAUST FILES WITH PROFILEA.EXE AND REVIEW THE OUTPUT GRAPHS
AND DOT PRA FILES.
NUMBER FOUR, LOOK AT THESE DOT PRA FILES AND MAKE A DECISION ABOUT THE TOTAL
DURATIONS, SPANS AND INTENSITIES TO SEE IF THE INTAKES AND EXHAUSTS WERE
ORIGINALLY INTENDED TO BE THE SAME !
NUMBER FIVE, SELECT THE BEST LOBE (LOBES) TO GENERATE A COPY TYPE PLATE
MASTER (MASTERS). NOW STRAIGHTEN THESE LOBES SO THAT THE BASECIRCLE RUNS
"TRUE" (OK, ALMOST TRUE). THE JOURNALS NEAR THESE LOBES OR BARREL AREA MUST
THEN BE GROUND CONCENTRIC, OR A SPLIT BUSHING IS PUT ON THIS JOURNAL, AND
THIS SPLIT BUSHING IS GROUND CONCENTRIC, WITH THESE NEW CONCENTRIC
BASECIRCLES. THIS WILL ALLOW A STEADY REST TO BE USED WHILE GENERATION THE
NEW MASTER PLATE.
BEFORE GENERATING THESE MASTERS, I RECOMMEND THAT THE ROCKER TABLE SPRING BE
CHANGED TO A WEAKER SPRING TO REDUCE THE LOAD ON THE SAMPLE LOBE TO BE
COPIED. IF THE SPRING CANNOT BE CHANGED, AT LEAST THEN BACK OFF THE SCREW
THAT PRELOADS THIS ROCKER TABLE SPRING. THIS WILL REDUCE THE "LOSS" OF CAM
LIFT THAT THE NEW COPY MASTER WILL NORMALLY HAVE !
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