No compression and tdc won't stay correct

[mad4106]

So I put my old head back on, we set it to tdc and when we rotated it counterclockwise with the socket it did not stay on top dead center it won't stay correct and then we put the valve cover back and thier was no compression I was turning with ease and it should had force which it didn't

[CJM]

So
1. Cam was installed lobes down
2. Cam gear lines up like this along head _ | _
3. When you installed everything you already had the motor at TDC?
4. The spark plug is in there right?

If all of that checks out take the head off and take about 1/2 cup of oil and pour it on top of the valves. Watch to see if the oil leaks past. Ifit does you need new valves and possibly a whole valve job with new seats cut.

Why did you put another headon anyways?

[mad4106]

I changed the head hoping that it would solve the chattering sound when revved up only it doesn't do it at idle it sounds like something is loose with my new head we checked timing chain and the slack and it was good and dowel pins were still in place underneath cam bearings

[dustin_j]

Make sure you are checking for TDC with the cam chain tensioner installed. Since all the tension is taken up on one side of the cam chain, the cam will rotate when you engage the tensioner.