Unless you dropped the crankshaft WAY down, it's pretty unlikely the gears have skipped any teeth. Not impossible, but I've never seen it happen. There should be factory marks to time the cam to the crank, and they will align every two turns of the crankshaft. The cam runs at exactly half crank speed, so there are twice as many teeth on the cam gear. When the marks align, there should either be a dot on each gear that will match up, or possibly there will be a dot on the crankshaft gear, for instance, and a dot or other mark on two cam gear teeth that will align on each side of the crank gear mark. I've seen timing gears set up both ways.
If the marks are indistinct, or missing, there's a way to check for proper cam timing. Remove the valve cover, and watch the motion of the valves on either #1 or #6 cylinder. Remove the spark plugs so the engine is easier to turn, have a helper turn the fan, and probe into #1 or #6 cylinder with a piece of soft wire (NOT a screwdriver, or anything else that's hard and unyeilding!) Turn the crankshaft until you can feel the piston come to the top of its stroke. One of the cylinders, either #1 or #6, will have both valves closed, with clearance evident at the rocker arms if you have a solid-lifter engine. The other cylinder's valves will will be "rocking", with the exhaust valve closing and the intake valve opening. Each valve will be approximately halfway of its travel. The relationship of the rocker arms and the piston position will be way off if the cam is out of time even one tooth. By simply turning the engine in the normal direction of rotation (clockwise when viewed from the front) and watching the valve action, it's pretty simple to check cam timing, even without timing marks.
Jerry
Last edited by Hotrod Lincoln; 07/13/2008 4:28 PM.
