If the dist is in and lined up with #1 plug wire and not off a tooth.
And using the witness mark you can observe that the dist. is not moving.
And #1 piston is truly at top dead center on the compression stroke.
And both #1 valves are fully closed.
Then you can eliminate timing chain skip.
Im thinking that if all of the above is true and verified, your harmonic balancer is bad.
They are a two piece construction with a solid inner part that goes on the crank and an outer "ring" that has the timing mark on it.
These are seperated by a rubber part that holds them together but is known to fail and makes the outer ring slip in relationship to the crank which makes the timing mark out of sync.
The other possibility is that the key and keyway on the crank snout have sheared off and the balancer is only being held by the bolt.
"StaticTime" the entire assembly.
Make sure the crank bolt isnt strippedor broken and if you try to spin the crank by using that bolt, pull all of the plugs first and go slow.
That bolt can strip the threads out of the crank and it can also break off in the end of the crank
And using the witness mark you can observe that the dist. is not moving.
And #1 piston is truly at top dead center on the compression stroke.
And both #1 valves are fully closed.
Then you can eliminate timing chain skip.
Im thinking that if all of the above is true and verified, your harmonic balancer is bad.
They are a two piece construction with a solid inner part that goes on the crank and an outer "ring" that has the timing mark on it.
These are seperated by a rubber part that holds them together but is known to fail and makes the outer ring slip in relationship to the crank which makes the timing mark out of sync.
The other possibility is that the key and keyway on the crank snout have sheared off and the balancer is only being held by the bolt.
"StaticTime" the entire assembly.
Make sure the crank bolt isnt strippedor broken and if you try to spin the crank by using that bolt, pull all of the plugs first and go slow.
That bolt can strip the threads out of the crank and it can also break off in the end of the crank