KLC piston height
Posted: Fri Feb 10, 2023 11:42 am
Hello All,
I have a question for all you motor guys. My 1953 KLC has one piston that is lower than all the others when it is at top dead center. I have the motor out of the boat and partially disassembled, was getting it ready to take it in for a valve job. As I was rolling it over by hand I notice the piston at the rear, nearest the reverse gear (stamped #1) sits lower than the other 5 when it is at top dead center. I measured all 6 pistons when they are at top dead center and they all fall between .015” and .020” below the top of the engine block…..except the rear piston (stamped #1) measured .075” below the top of the engine block. So that one piston sits about .060” lower than the rest. That’s a 1/16” of an inch……seems very odd to me. My first thought was there is a different piston in that cylinder, but all 6 pistons have the same identification/part number stamped on them. Also, there is no slop or looseness when you roll that cylinder back and forth over top dead center, like you would see and feel if you had a severely worn wrist pin or worn piston pin bore or bad rod bearing and there was no engine knock/slap when it was running that would indicate worn wrist pin or rod bearing. So I don’t believe any of those parts are the culprit. Has anyone seen this before?
I attached a couple of pics. Cylinders 1 and 6 come to top dead center at the same time, so the 3 picks are with #1 and #6 at TDC. You can easily see the difference.
And thoughts would be appreciated.
Thanks,
John Mears
I have a question for all you motor guys. My 1953 KLC has one piston that is lower than all the others when it is at top dead center. I have the motor out of the boat and partially disassembled, was getting it ready to take it in for a valve job. As I was rolling it over by hand I notice the piston at the rear, nearest the reverse gear (stamped #1) sits lower than the other 5 when it is at top dead center. I measured all 6 pistons when they are at top dead center and they all fall between .015” and .020” below the top of the engine block…..except the rear piston (stamped #1) measured .075” below the top of the engine block. So that one piston sits about .060” lower than the rest. That’s a 1/16” of an inch……seems very odd to me. My first thought was there is a different piston in that cylinder, but all 6 pistons have the same identification/part number stamped on them. Also, there is no slop or looseness when you roll that cylinder back and forth over top dead center, like you would see and feel if you had a severely worn wrist pin or worn piston pin bore or bad rod bearing and there was no engine knock/slap when it was running that would indicate worn wrist pin or rod bearing. So I don’t believe any of those parts are the culprit. Has anyone seen this before?
I attached a couple of pics. Cylinders 1 and 6 come to top dead center at the same time, so the 3 picks are with #1 and #6 at TDC. You can easily see the difference.
And thoughts would be appreciated.
Thanks,
John Mears