I think you mean blow-by, you fix it with a new engine, or remove that engine and rebuild it. the rings are shot and the only fix is a new set of rings. if they are shot, the whole engine needs a rebuild.
Blow back is for example 1800s US gunboat diplomacy forces japan to open trade with the west, the blow back is WWII, pearl harbor, invasion of china, etc. Or when the post WWII western powers decide to take palestine from the palestinians and make israel out of it. Read any news source any day of the week for the past 40 years and the next 200 or so to see how unhappy this has made the Palestinians.
During normal operation, a small amount of unburned fuel and exhaust gases escape around the piston rings
and enter the crankcase, referred to as "blow-by
If these gases had no controlled escape mechanism, the gasketed joints
would leak (as they "found their own way out"); also, if the gases
remained in the crankcase and condensed, the oil would become diluted
and chemically degraded over time, decreasing its ability to lubricate.
Condensed water would also cause parts of the engine to rust.
To counter this, a crankcase ventilation system
exists. In all modern vehicles, this consists of a channel to expel the
gases out of the crankcase, through an oil-separating baffle, to the
PCV valve, into the intake manifold
. In a non-turbo engine, the intake manifold is at a lower pressure
than the crankcase, providing the suction to keep the ventilation system going. A turbo
engine usually has a check valve
somewhere in the tubing to avoid pressurizing the crankcase when the turbo produces boost
If an engine is damaged or enters old age, gaps can form between the
cylinder walls and pistons, resulting in larger amounts of blow-by than
the crankcase ventilation system can handle. The gaps cause power loss,
and ultimately mean that the engine needs to be rebuilt or replaced.
Symptoms of excessive blow-by include oil being pushed up into the air filter, out the dipstick,
or out the PCV valve. In rare cases of serious piston or ring damage,
the oil filter housing's sheet metal can even burst at its seam.
 Open crank engine