Well it wasn't the valves/lifters(adjustment), fuel pump or water pump noise. Originally I thought it was a rod bearing, but it wasn't knocking. Well I pulled the head because it finally let go on the lake and had to get towed in. It was the number one piston. I was able to hone the cylinder and...
Have a 1975 gm 165hp inline6 with a lifter like noise.
Sounds like it's from the front of the engine at the middle or lower by the crank. hard to tell
here's what I have tried: adjusted the valves cold(not running) per the service manual.
adjusted the valves engine running(normal temp).
nothing...
