So I got a beautiful, ultra low mileage head (with gears, cams and chain)from, supposedly an 07 cobalt, matching 133 casting numbers. Put it on and timed everything, all new components, and no start, compression of only about 40lbs. Double/triple checked everything. Finally I mocked up the 08 head and cams, pulled the valve cover again on the 07 head and lined everything up and found that the exhaust cam is about 180º off and it opens right after the intake cam. On the 08 you can clearly see the exhaust lobe is past the follower and the intake cycle can start. I found a mention of 07 cobalt cams being all alone.
I looked up timing procedures on 07 cobalt and the 08 hhr and they are identical, 10 o'clock exhaust and 2 o'clock intake and 5 o'clock crank. All 3 sets of gears are timed identical and all 3 chains have the same exact black link locations. The exh and intake marks aren't 180º off, more like 160º or so, but im wondering about the option of using the intake mark on the exhaust cam, but I am now planning on swapping in my old 08 camshafts. The cams have different grind numbers also.
Ive been an ase master and chrysler gold tech for 20+ years, im not crazy but this is making me feel like I may be. Does anyone have any insight into an odd, one off type exhaust camshaft?

 

Any chance that the head has 2 of the same cams installed ? (like 2 intake cams installed instead of 1 intake, 1 exhaust)?
Not even sure if they'll fit on the wrong side, but just guessing.

 

No, the intake cams are a few inches longer, that was a thought, I was hoping there were part numbers in the cams, but so far I have only found grind numbers. I'm going to check with my gm resources today and hopefully find some answers.

 

The head doesn't have a couple extra holes in it, like where VVT valves might go, does it?

Maybe the cams are reversed, intake for exhaust?

Not a slap the forehead moment and got the sides mixed up. Or, diamonds and triangles mixed up.

Or, setting the crankshaft straight up or down instead of 5 o'clock.

The part numbers between 2007 Cobalt and 2008 HHR are the same.