Hello everybody,
I have 1.8 16v Stilo Dynamic and I have excessive oil consumption too - 1l per 500/600km engine is clean, almost like new.. No smoke signals during startup and ride...
the low oil pressure warning occured only twice, when I had too brake rapidly. From that time I try to have the oil level on the MAX mark on the dip stick. The engine had 101000km on the clock and big repair to solve was performed on 98000...
I tried to solve it last summer. However without succes so I have "spare" block from Barchetta with Barchetta pistons.
The repair:
I disassembled the engine, took the head to specialists where it get the best care (new sealings, checked valves and guides, mildly "ported" to correct manufacturing imperfections and rounded valve seats and valves for best airflow, new hydro-lifters vere also putted in because of erosion on contact surface wich could damage camshafts in future.. erosion probably caused by low grade quality oil wich also caused piston ring and cylinder bore wear)
So by this step I ´ve eliminated the head from the list, but the more was found in the block.
Piston ring were badly worn - almost 1mm gaps in the lock and step on second ring disappeared too, the cylinder wals were glazed with smal step in TDC and BDC with honing wisible on surfaces where ring dont go - difference in diameter was 0,015mm so nothing unusual... I´ve deglazed the cylinders (steps dissapered), tried tu put in new ring -with gap of 0,3-0,35mm (acc to workoshop manual) wich should improve the oil consumption rapidly and assembled the engine with hope of better oil consumption...
After some hunderts km of bedding in, the engine felt and sound like new, but after check of oil leve I was dissapointed - oil consumption remains...
I checked the spark plug to find weter its from head or block - all plugs vere badly foulded and pistons were wet - conclusion head is OK, problem is in block...
so I ve obtained barchetta block with pistons - wich are older desing, heavier and with thicker piston rings (1,5/1,5/3mm instead of 1,2/1,5/2mm)..
Interesting is that many problems with oil consumption comes with new engines with thinner piston rings and lenghtened oil change intervals - on 1.6, 1.8, 2.0 and 2.4 5cyl engines engines with thicker rings are almost OK..
http://hno3.rajce.idnes.cz/stilo_motor/#