Blow-by on rebuilded engine?
Posted: September 30th, 2011, 6:04 pm
Hello,
I have one question regarding to blowby on engine.
I have Fiat Stilo 1.8 16v (same as Punto HGT, Barchetta, Lancia Lybra etc- engine type 192A4.000..). In recent days I tried to solve excesive oil consumption wich was almost 1l/800km.
I was decided to change all parts wich could affect oil consumption and repair/refubrish remaining parts.
- Head was checked and slightly modified (three angle valve seats, modified valves, cleaned ports and removed mismatch). Valve guides were measured and their measures are within the factory tolerances. Valve stems were sealed with new sealing rings. After carefull check of hydraulic lifter 8 were scraped because of erosion on contact surface and new ones take their place.
-pistons and bores were checked, bores were subsequently deglazed with flexhone (my first experience with this wery nice and usefull tool!) .
What is amazing on this engine is the fact, that it has only 1.2mm; 1.2mm and 2mm thick piston rings and nicely designed , wery light pistons.
Old piston rings had a gap 0,8 (first sealing ring)- 1mm (second ring), new rings has 0,3-0,38 mm. So it was probably the main reason for this oil consumption...
Today i started the engine-and what is interesting - when I remove the oil cap the engine has quite simmilar blowby (if i can name this effect this way) to engine before this repair.
First of all - rings are not bedded in yet- I will bed the engine tommorow.
Secondly - could the "blow by" through removed oil cap be caused by the design of crancase ventilation?
its only ventilated through the valve cover. There is no hose directly conected from crankcase to intake manifold.
I´ve attached scan from Fiat repair manual regarding this system (I hope that it isn´t break site protocols, in other case i will remove the picture)
REMOVED BY GC DON'T YOU HAVE ANY IDEA WHAT COPYRIGHT IS?
all comments or ideas are welcome
I have one question regarding to blowby on engine.
I have Fiat Stilo 1.8 16v (same as Punto HGT, Barchetta, Lancia Lybra etc- engine type 192A4.000..). In recent days I tried to solve excesive oil consumption wich was almost 1l/800km.
I was decided to change all parts wich could affect oil consumption and repair/refubrish remaining parts.
- Head was checked and slightly modified (three angle valve seats, modified valves, cleaned ports and removed mismatch). Valve guides were measured and their measures are within the factory tolerances. Valve stems were sealed with new sealing rings. After carefull check of hydraulic lifter 8 were scraped because of erosion on contact surface and new ones take their place.
-pistons and bores were checked, bores were subsequently deglazed with flexhone (my first experience with this wery nice and usefull tool!) .
What is amazing on this engine is the fact, that it has only 1.2mm; 1.2mm and 2mm thick piston rings and nicely designed , wery light pistons.
Old piston rings had a gap 0,8 (first sealing ring)- 1mm (second ring), new rings has 0,3-0,38 mm. So it was probably the main reason for this oil consumption...
Today i started the engine-and what is interesting - when I remove the oil cap the engine has quite simmilar blowby (if i can name this effect this way) to engine before this repair.
First of all - rings are not bedded in yet- I will bed the engine tommorow.
Secondly - could the "blow by" through removed oil cap be caused by the design of crancase ventilation?
its only ventilated through the valve cover. There is no hose directly conected from crankcase to intake manifold.
I´ve attached scan from Fiat repair manual regarding this system (I hope that it isn´t break site protocols, in other case i will remove the picture)
REMOVED BY GC DON'T YOU HAVE ANY IDEA WHAT COPYRIGHT IS?
all comments or ideas are welcome