W123 Cam timing help!!!!!
 

Just purchased another w123 300D. The car was not running as the owner had started a cam chain replacement, dropped the chain, and gave up. Well, to make a long story short, I bought the car and fished the cam chain out (amazingly it was still around all of the sprokets). So here goes, the timing marks on the cam tower and sprocket line up with the balancer, but it doesn't seem like they do on every rotation??? Could this be true, or am I missing something? I just rotated it, hit dead on zero on the balancer. Rotated it again, way off advanced, rotated again, way off retarded. Am I missing something here? This is my first time playing around with this, so any help would be appreciated. The car "seems" to turn over okay with no noticbale binding. How do I get this thing back so I can fire 'er up?

Cheers

Jeffrey

Everything should line up when the cam lobes on the #1 cylinder is pointing "away" from the piston - this is TDC on #1 cylinder. If you are able to rotate the engine through multiple cranks that tells me that it sounds like everything is probably ok. You would not be able to rotate it if the timing was wrong because the valves and pistons would be in the same place at the same time. If I remember correctly the #5 piston and # 1 piston are at the top at the same time but only one of them is at TDC compression at a time.

The #1 piston is on the exhaust stroke when the cam notch doesn't line up and on the compression stroke when it does line up. This is an every other rotational even. In other words, it takes two revolutions of the crank to equal one revolution of the cam shaft.

Good luck.