[Formulajones]

Originally Posted by TRADERMIKE 2012

To find the actual ICL, we placed the Dial indicator over the edge of the Intake Valves Hydraulic Lifter and measured the duration of the Cam @ .050" on both sides of the Valve duration Ramps by passing the .050" mark on the Dial Indicator first then moving toward the .100" mark first then rotating back to exactly 050", where we took our readings off the Degree wheel # and recorded that number, adding those numbers and dividing by two equals 112 degrees for the Intake c/l and 115 degrees for the Exhaust c/l, then to obtain the lobe separation angle we added these two numbers and divided by two equals 113.5 degrees.

We advanced the Valve Timing from 113.5 to 109.5 by using the Comp Cam four-way Crank Gear, each notch is two degrees according to their directions, thus the fourth notch equals 8 degrees at the Crank and that means 4 degrees at the Cam. Because the Crank rotates twice, 720 degrees and the Cam rotates once 360 degrees. 360 degrees at the Crank equals 180 degrees on the cam, the Crank spins 2x the Cams one. Half a turn at the Cam is equal to one rotation of the Crank.

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OK you used the .050 method with a dial indicator. As Jay mentioned I hope you went back and checked again after you moved the crank gear.

Those crank/cam gears, as well as keyways on the cam and crank themselves are notorious for being off a few thou here and there affecting the degree readings. So just because it says 4 degrees or 8 degrees on the crank gear, doesn't mean that's what it moved. It could have be 5 or 6 or only 2 or 3. It'll have to be checked again if you want accuracy. In most cases from my experience you end up a half degree or even a full degree one way or the other and that's as close as it gets.