Thats a great idea with the lifter pre-load spring Walt! Kinda hard to do on the 455 with no heads on tho. Your method will render a consistent "ZERO" even against a film of oil. Thats not much but it is "consistent". I think I need to make a "travel stop" for the piston. Ive never done this before, so if I'm going through the motions, I may as well learn it and learn it proppa! The hardest part about 0* at TDC is in both directions having to stop at ZERO and go NO MORE. That makes a dozen or so "lash trips" in everything if you go past the mark. I was getting "consistent readings within 1 or 2 crank degrees. The TDC piston dwell is running about 1-1/2 crank degrees as well. Its just more difficult to do the math in the middle of a process.
All Ive established with the stock single key crank gear, is that the timing marks come back to "dot to dot" with the piston at TDC. It doesnt show any relevance to the actual cam retard or advance. If you look at my wheel, its secured to the damper, so theres no way to center the marks between CC or CCW on the crank degrees. Gotta do the math on that one!
Once thats done, I can then measure minus .050" on the piston TDC for initial valve opening and closing. So far its "ABOUT 110*" and the card calls for 112*. Close enough? Maybe; but I'd like to try and get it where its supposed to be. Please let me know if I am beginning to grasp the concept!
As it sits, with the forged and balance pistons and rods, the piston top is at about .055" below the deck height. Thats just a little more math to determine TRUE TDC. I am using #1 piston with no rings, but attached and tightened rod big end to the crank. Its much easier to roll over with no rings on it! Please negate the dial indicator needle hysteresis!
"A property of a system such that an output value is not a strict function of the corresponding input, but also incorporates some lag, delay, or history dependence, and in particular when the response for a decrease in the input variable is different from the response for an increase. For example, a thermostat with a nominal setpoint of 75? might switch the controlled heat source on when the temperature drops below 74?, and off when it rises above 76?.
Magnetic friction in dynamos, by which every reversal of magnetism in the iron causes dissipation of energy." Bill