Here is what i've been doing with the HHR. I took off both chains & set them up correctly. The cam gears were also set at 10 exhaust & 2 intake on the compression stroke, & I reset the timing chain tensioner (by taking out the snap ring & resetting it). I rotated the engine by hand a few times (with the spark plugs removed) just to see if I could tell if the valves were hitting the pistons, but it rotated smoothly without any noise.
Before starting the engine I decided to go to the parts store & rent a compression tester. The compression on all four cylinders were #1-20 psi, #2-0, #3-0, #4-0. I tested it multiple times to make sure. I then checked the compression on my camaro & the compression tested normal, so I knew the tester was working properly.

I didn't want to try to start the engine anymore after the compression test, so I just removed the cylinder head. I didn't see any bent valves, but i could tell that the exhaust valves had barely hit the pistons because each piston had two clean spots where the carbon had been scraped off by the exhaust valve, but there wasn't any visible piston damage.

So I had the head completely rebuilt at a machine shop, & the guy said that many of the valves were not seating properly. I re-installed the head with new head bolts, re-installed both chains, new cam bolts, new crank bolt, & now the car runs like brand new again, but without the timing chain rattle at start-up.

We must have rotated the exhaust cam too much during the initial timing chain install.

Thanks for all of the help guys, I really appreciate it.

 

Live and learn. Happy ending. Enjoy yer like-new HHR!

 

Awesome, thanks for the follow up, enjoy the drive!