Originally Posted by
quietstorm76
Don't have a Sonic but I have the new IDM RCW Modified and I noticed the tapping noise too. It seemed to go away once the engine was warm so I didn't worry about too much. Still weird because it doesn't happen on the stock IDM RCW. They both are fast though so time will tell.
I found the problem last night, I unstall the heat sink, and I double check all the bearings before reinstall the engine.
I found the head and sleeve have little movement in between, I have to carefully torque the bolts evenly. I think the head and sleeve is not align properly. Now, the pinch zone towards TDC is smoother.