Timing
If you have taken you head apart, which would include taking the rocker arms off anyways to replace valves.... You absolutely need to adjust you valve lash via the rocker arms, and then put a few miles/heat cycles on the motor and then check it again to see if any rockers came loose. You can destroy pushrods and sometimes more if they come loose. I have a gas pulling truck and I went one pull too long before checking the lash again, it was too late, lost 6 push rods because they slid past the rocker arm and twisted. Also lost a vertical bar roller lifter and the camshaft because one of the rods hit the bar on the lifter set, broke it and the lifter turned in its bore scoring the cam terribly... As you can see, its a chain reaction type thing. Also, as long as you didnt have the shop take any material off of the deck of the head, you shouldn't need to check the piston to valve clearance if all the valvetrain is stock replacements.
CP
CP
How do you check the clearance between the valves and the piston? Train a mouse to go in the injector hole with a feeler gauge?
Initial looks at the clay... If anywhere in the clay to see a bare spot (the top of the piston), you have interference guarenteed. Remove the clay and use a pair of calipers to measure the thickness where the valve impressions are. You can also cut the clay in half to get a more accurate reading. Be careful not to crush the clay with the calipers. Most engine builders will tell you a minimum of 0.100" is the required piston to valve clearance. This allows for timing chain slack and also any cam variances between different lobes on different cyliders.
Sorry for the book, lol.
CP
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