No special break in, just make sure there's good oil in there and run it.

Glad you found the issue, I had a similar **** up on my car, I actually forgot to tighten the cam gear bolts. I had put them on hand tight when doing the timing chain and never went back over them. Intake cam gear jumped on the cam, broke the teeth inside the gear off and bent valves on #1 and #2 cyl. I just replaced the valves and gear and put everything back, fired right up.

 

So I got it all put back together. Cranking it and no joy. Where should I start trouble shooting?

 

Check basics... got fuel pressure? Plugged in everything? Good ground on the engine? Got rpm signal from the crank?

 

Compression check is good, got spark, the plugs smell a little like gas but I can't really tell. I plugged in my Bluetooth obd and used my torque app to try and check fuel pressure. I've never used it before but according to it I've got 4 psi.... so that's bad. It's also poping a P0627 code. Is there a way to test if my high pressure fuel pump is messed up? It was functioning before I pulled the motor apart, is it possible to put it in the head wrong?

 

It's a circuit code so there's probably something not plugged in.

 

I'll admit it, I'm a dummy. I forgot I removed the fuel pump fuse while I was diagnosing before tear down. Popped that baby in and it fired right up. Runs great! Got a small coolant leak somewhere on the back side of the motor. gonna have to sniff that out. But I sure am happy that the rebuild was a success!

 

That's awesome that's all it was.

 

Just to close out this thread, I've been running now for 1000 miles and the car runs great. To recap, I picked up a 2009 Cobalt SS that wasn't running. The car had no compression and the results of the leak down test showed the valves where not closing. The timing chain was loose and had likely jumped. Upon removal of the head it was obvious that all of the valves where bent, fortunately it did no damage to the pistons or cylinders.

I installed a new head gasket (eBay $34), head bolts (eBay $27), timing set (eBay $73), and new assembled cylinder head (eBay ZZP $250). Once I got it all put back together and tried to fire it, I had no fuel. I was a dummy and forgot to put the fuel pump fuse back in. Plugged that in and it fired right up and ran great, however it was leaking coolant. I discovered that the water pump gasket failed because the two front water pump bolts came out during the timing set install. So I got a water pump hold tool (Amazon Lisle 13800 $26), water pump (Amazon $27), and a thermostat (Autozone $6), installed all of that and now shes running great with no issues.

I recommend changing the pump at the same time as the timing set, why not, you're already there.

Thanks to everyone that weighed in on this matter, it was a great help. If anyone needs help with similar problems hit me up I'd be glad to help.

 

Nice ending to a thread, I'm glad you got good results, and thanks for the write up.