im putting the new vavlesprings on the ls1 and im having some trouble. when i put the air hold in, all is fine but as soon as i start to compress the springs, its as if something gives way and all the air pressure starts exiting through the intake port from the heads and the exhaust ports and the valves stay up. the engine does not have the intake on it nor headers and i can feel all the air escaping from there. Any ideas of what is going on?

 

You ain't pushing on the valve stem are you....that would just lead to the evacuation of the air. Make sure its seated on the retainer and not the clip or valve stem.

 

Give the top of the valve and keepers a couple good taps with a rubber or dead blow hammer to help free up the keepers.

 

just from experience, just in case make sure as an added precaution to put the piston at top dead center while you are working on that pistons springs

I actually didnt even use air when I did mine. I just compressed the spring until the valve touched the piston, then gave the spring a light tap with rubber mallet to release the retainers. may not be the best plan but it was stock heads and I was planning on replacing them anyway, but after the spring and cam install the car was one of the best running ones around