Chain SlacK
 

560 sel 87, if the timing chain is tight after replacing the upper 3 guides and the tensioner and there is still a lot off chainslack "between the the camshafts" is the the bottom rail bad??

Have not replaced the chain yet and will do so now but the slack is present with all timing marks right on and crank is at 8 degrees After tdc., which is not too bad with old chain I guess, but I don't understand the above mentioned slack??

thanks
John1

You can not use the chain slack method to tell anything. 8 degrees is the 2nd worst I've seen in some 30+ M117 timing chain jobs.

The slack will "move around" the engine..something you'll find as you turn the engine over by hand.


Jonathan

In addition to Jonathan's point, it's worth noting that the tensioner requires oil pressure to do its thing. It takes several cranks of the engine to build up enough oil pressure for that tensioner rail to come out, and as the pressure falls away the rail will retreat into the rest position. So even after you have replaced your chain you may still see some slack when everything is at rest.

This is why, after changing the oil, it is so important to crank the engine over with a disabled coil for 25-30 seconds to build up healthy oil pressure. We don't want that slack to bunch up under a rail or cause us to jump time.