U20 Death Rattle On Start-up
There was a great discussion on this on the forum. Dave Bricso pretty much hit the proverbial nail on the head. Even after new timing components people still had the rattle of death. The reason for this is the upper tensioner relies on oil pressure to exert enough force to take any slack out of the timing chain. Until you have sufficient oil pressure you can experience the rattle of death.
Mr. Brisco's take on this:
The spacer would go on the shaft, between the arrows to make it retract less. Many people have used washers . I went a different way. The tensioner has a weak spring and is pushed out fully by oil pressure, so I put in a piece of an oil pump relief spring, much stronger, from a Buick that gave a bit over 25+ pounds static pressure on the tensioner, same as exerted by 75-80 PSI of oil pressure. No noise on start up, ever. Spring assortment at the local Sears should do it if you don't have a 75 Buick oil pump lying about the garage.
As Will mentioned, the shims are a more positive method, they prevent backlash. IMHO, I would leave maybe 1/8 or so free play for expansion.
The popping of the chain over the tensioner, if it's not the cam/valves may be a stiff link. mark the chain and see if it only does it as that one spot passes by. Chains are cheap compared to the rest. available from Cloyes.
BTW if you are removing the head, the nuts visible in the photo need to be removed...I mention this because I always forget them. :(