You don't need to blow oil back. First order kit from Schindler or dl Martin. It contains a type of stand to hold piston up inside of the cup. Place car on sticks and close shut offs. Use small hoist( I hang it off a c clamp on the triangular metal near jack). Use small piston clamp to hoist piston sections neat a time. There are very small set screws all around each head ! Remove the snap ring at bottom and hoist piston slowly. Use vacuum to suck up the oil that comes out( should only be about 10-15 gallons). Place stand under piston and hammer down head. Hoist piston up again and remove head from stand. Repeat for all sections.