intake valve overlap

[robmog]

when setting the overlap, where is my zero point?
after my first 360 crank rotation my valve moved about .005"
do i just keep going to my value or do i zero my dial gauge and go from there?
thanks,

[cgarr]

Zero at tdc on number 1 or close to it, that valve will not show any movement until you come around 1 turn anyhow, that's the power stroke. One full turn and read the gauge back on the tdc mark which will be the exhaust.

[robmog]

thanks once again craig

[lindy 911]

Make sure you pre-load the dial indicator and then zero the face at TDC before you turn the crank. This will ensure that the dial indicator is seated on the spring retainer without any slop. This is what they refer to as "zeroing the indicator".

It's really very simple. The exhaust and intake valve are open at the same time at overlap, with the exhaust valve just about closed and the intake just starting to open. The way you set the timing of the cam is to measure how far the intake valve is open at TDC. The dial indicator needs to be resting on the valve spring retainer before the valve begins to move. The pre-load of the dial indicator simply makes sure the indicator is firmly seated on the retainer. Once there is some preload and everything is tightened up on the dial indcator, set the face to zero. Now you can start the timing process.

Lindy

[2.70Racer]

Lindy,
Your's is a very simple, clear explanation of the cam timing process.
Well written.