Hello, i can tell there are many experienced mechanics on this forum, and i would appreciate some advice.
i am investigating a knock sound from an inline 6 115 ADI.
the engine was running, but with some minor problems. it idles like crap, and is hard to start. once hot there is no problem accelerating or running, exept for some mild hickups in between. and there was a pretty loud knocking sound that followed RPMs. timing was 5BTDC pickup and 20 BTDC max at cranking speed. compression was 120 on all cylinders. carbs and pump are completely rebuild with floats and needles, with levers adjusted to 10mm/6.4mm.
i pulled the motor to investigate the knocking sound. there are a number of issues. all cylinders have scoring below the intake and exhaust ports, but no scoring above ports. what effect does this have on engine performance? and what is the cause? foreign objects?
some pistons are re used ones in pretty bad shape. i am trying to read the pistons, but have little experience. there were no stuck rings on any of the pistons.
the image below is of the worst looking piston, and the one thing i noticed was the bell curve shape on the skirt. this shape is on all the pistons. is there anyone who knows what made this shape on the piston? i really need to find the source of my troubles before i assemble with new parts.
i found no evidence of wear in the labyrinth inside the reed blocks. altso in what way could the imbalance caused by scoring on pistons affect the engine?
i am investigating a knock sound from an inline 6 115 ADI.
the engine was running, but with some minor problems. it idles like crap, and is hard to start. once hot there is no problem accelerating or running, exept for some mild hickups in between. and there was a pretty loud knocking sound that followed RPMs. timing was 5BTDC pickup and 20 BTDC max at cranking speed. compression was 120 on all cylinders. carbs and pump are completely rebuild with floats and needles, with levers adjusted to 10mm/6.4mm.
i pulled the motor to investigate the knocking sound. there are a number of issues. all cylinders have scoring below the intake and exhaust ports, but no scoring above ports. what effect does this have on engine performance? and what is the cause? foreign objects?
some pistons are re used ones in pretty bad shape. i am trying to read the pistons, but have little experience. there were no stuck rings on any of the pistons.
the image below is of the worst looking piston, and the one thing i noticed was the bell curve shape on the skirt. this shape is on all the pistons. is there anyone who knows what made this shape on the piston? i really need to find the source of my troubles before i assemble with new parts.
i found no evidence of wear in the labyrinth inside the reed blocks. altso in what way could the imbalance caused by scoring on pistons affect the engine?
