2.5 fishing motor blown cyl#5

[76horizon]

motor has been rebuilt 3 times and now .03" over in hole 5 motor lasts about one hour use.injector has been changed and all other cylinders are like new. the cylinder is scraped up but the top of piston is black and in perfect condion.stats are both working.original sleeve.possible water through exaust port? block? something stupid im over looking? please help

[Dave S]

What rod....

[76horizon]

what do you mean?

[Dave S]

What con rod what crank.... with cheek?

[TEXAS20225]

could be the sleeve it not touching the sleeve holder in enough places causing the heat to not transfer to the block and the piston sticks

[Jay Smith]

Hopefully your breaking in on "dino" oil only ! Make sure machininst is giving you the proper clearances. If your building the motor yourself check the ring end gap MUST be at least .016" MIN .On over bored pistons I always give them a bit more claerance too. 1/2 thou. on .015" over and a full one thou on .030" over..If this bore has been the "bad egg" pull the sleeve and have an over sized OD sleeved replace the bad one if there is a voild in sleeve contact it will create hot spots and will NEVER live !!!

Good luck,
Jay