I have a problem with F7P engine. It was in very bad condition: worn pistons and cylinders, lots of rust in engine coolant system, engine internals full of sludge... I fully recondicioned the engine; everything cleaned and thoroughly inspected, all oil passages and coolant passages cleaned, oil spray jets checked, oil relief valve, oil pump. I put new pistons 1mm overbore, new big end bearings (0.75), main bearings (0.75). After machining everything is measured and checked again 0.04mm piston to wall clearance. New thermostat and fan switch.
Put it all together and engine runs nice and pulls strong when it is cold. When it warms up there is big loss of power and it slightly overheats and oil pressure drops. I made 50 km maybe. I disassembled it to see what is going on. I found slightly damaged cylinder walls at the bottom near oil spray yets. After several attempts to fix this issue i found that cylinder block liners are deforming when engine warms up. Then i torqued head bolts to a lot smaller torque than specified and it was better but not as it should be.
After machining, cylinders had very small black dots (0.1 or smaler diameter) all around like they are porous. I noticed this and ask machinery technician about this. He sad this is not a problem. Obviusly there is a problem with cylinder wall distorsion when engine weats up.
So my question is: do you have any knowledge about F7P engine block problems, like porousity, or material structure problems due to high mileage with poor servicing and maybe overheating?
Please help
Put it all together and engine runs nice and pulls strong when it is cold. When it warms up there is big loss of power and it slightly overheats and oil pressure drops. I made 50 km maybe. I disassembled it to see what is going on. I found slightly damaged cylinder walls at the bottom near oil spray yets. After several attempts to fix this issue i found that cylinder block liners are deforming when engine warms up. Then i torqued head bolts to a lot smaller torque than specified and it was better but not as it should be.
After machining, cylinders had very small black dots (0.1 or smaler diameter) all around like they are porous. I noticed this and ask machinery technician about this. He sad this is not a problem. Obviusly there is a problem with cylinder wall distorsion when engine weats up.
So my question is: do you have any knowledge about F7P engine block problems, like porousity, or material structure problems due to high mileage with poor servicing and maybe overheating?
Please help
