as the title says i just did the initial start up of my new engine. idles fairly well but has a "clacking"noise reminds me of a rod knock ? I let it idle for a little bit and i tried to give it a little gas. it wont rev ?. I adjusted the valves and double checked the timing. everything is fine. so now im stumped is it the brand new built block or piston/valve contact? any input would be appreciated! thanx

 

Did you measure everything for proper clearances during the build and before you started the engine? The person who checked the clearances and built the engine would be the person to ask about piston to valve clearance problems.

A little info about the build the parts that you put into it and what your using for engine management would also be helpful.