How do you know #1 cly is at tdc?
By using the dial gauge to measure a dropped valve against the
piston top. But you almost never need to know this, unless
something has been messed up. You certainly don't need to know
it to measure chain stretch. Line up the marks and read the
stretch off (in degrees) the timing scale. If you _really_
care you can use trigonometry to convert this number into a
linear stretch factor. A useless number since nobody cares
about it, nor is it specified anywhere. Everybody uses the
degrees scale.
the cam until the mark is close. It can be frustrating as often the
compression will not allow the engine to stop at the proper point.
Just be
patient.
Going slower allows the compression to bleed off, preventing
it from pushing itself past where you want to be.
-- Jim
