Cam Degreeing/Checking Important

[40 Deluxe]

Originally Posted by frnkeore

The general way of finding TDC, is to rotate the crank, only clockwise, while picking up locations.

Set the dial indicator on the piston and find the approx top of the stroke. Rotate again, set the degree wheel at 0, when the indicator gets to .100 BTDC, then rotate until it's at .100 ATDC. Divide the number of degrees by 2 and that is TDC. Next rev, stop the crank at that number and reset the degree wheel to 0.

You can use any number on the dial indicator but, .100 is covenant.

If you use a bump stop, you'll be close but, you won't be at TDC, because of the back lash, between the crank gear and the cam gear and that's why you only turn the crank CW.

You don't have to turn only CW but, if you don't, you have to go well past your locations and start turning CW again, to be sure you've taken the back lash out.

Backlash? The only backlash involved in finding actual TDC with the positive stop method would be the oil clearance in the rod bearing! The timing gears are not involved in finding TDC. Since you're no doubt using very light checking springs, just hold the cam gear clockwise (against rotation) to take the backlash out when checking the cam timing.