I have a 91 ford f150 with a 302. One mechanic says its bad rod berings another sais bad valves or springs. Without tearing out the motor is there any way to tell which is the problem. When coo the engine sounds fine but when it warms up you can hear a slight ping but the sound seems to travel from right to left side

 

Junk it and buy a chevy

 

You're first problem is asking a ford question on a chevy message board.

 

the problem should be circled on the front...