Later slant 6 engines had a timing scope on the front of the block . A curved piece of brass with a tube in the middle to shine a timing light through. Does anyone have a extra timing mark like that?
Ya what he said. I new the tube was for a timing probe but until now I never knew how it worked. Thanks for the learning.I think a variable reluctance probe was inserted in the tube, it picks up a narrow notch in the pulley at TDC. A VR probe is a coil on a slug with a bias magnet, when the notch is encountered a pulse is generated. The pulse would be used to trigger scope, then the 6 cylinders could be viewed inline as pattern 3 per revolution. It is also a means to measure spark advance with scope, I conjuction with coil primary signals.