I did a leak down test on my spare 3k mile motor out of my totaled z. All cylinders came back with zero leak down except cylinder #3. I found 70% leak down on the exhaust side. For some reason the exhaust valves weren't seating.
I decided to install my spare flywheel, trans and I bought a starter off Ebay so I could turn the motor over and see if I could get the valves to seat. They wouldn't seat cranking it by hand.
Filled her up with oil and cranked it for a few minutes. Got #3 cylinder back up to 50% leakdown. Since I could crank the motor over I decided to do a compression test. I borrowed a compression tester and ran all cylinders. The numbers were all over the place on all cylinders. From 60 to 85 psi. WTF. The leakdown came back perfect on all cylinders except #3, how could I have low compression on all cylinders. Must be a bad gauge.
Went to HF last night and bought one of their better gauge sets. As I was watching TV I started wondering what else might cause the low numbers and then I remembered I forgot to take off the tape covering the lower intake manifold ports to keep debris out, upper manifold was removed).
Went back today, took the tape off and did a re-test. All cylinders tested between 260/265 except #3 which was 180. I let the motor crank with the starter for about 10 minutes and then tested #3 again. Came up to 265.
I'll be wearing this cap for a while