I just took the shrader valve off my cheap autozone compression tester so it would allow air to enter the piston then hooked it up to the compressor. Easy way to tell if you have bent valves. Qustion tho i set the piston at tdc for each and then rocked the crank back and forth till i head more air comming out the intake then axhuast to find the excasct center. At this exact center there was leakage for both the intake and exhust so i guess that means i have hent all my valves. Should there be commpression at some point when they are all closed?