I have a freshly built L61 Ecotec still on the engine stand. I set the engine to TDC cylinder #1, installed my cams close to where they should be and proceeded to put the chain on. Everything looks good, the crank sprocket is at around 5 o'clock, the cams at 10 and 2. my problem comes from when I put some air in the cylinder. I can feel air coming from both the exhaust and intake ports on cylinder #1. cylinder #4 is sealed up tight no air leaks other than a bit from around the rings which I believe is normal on a dry engine. I have done the timing over just to be sure I didn't miss anything. The valve train is all new, all the timing components are all new, as well as the camshafts.

I was under the impression that the #1 cylinder should be at the top of the compression stroke, and therefore no air should be escaping. Is that not correct? Is there something simple I'm overlooking?

 

I turned it over once to TDC again and there were no bad noises and cyl#1 is now at the compression stroke. the cam gear marks are opposite now.

 

During exhaust stroke both valves are open at TDC.