L;
It was the beginning of the government's over regulation of the auto industry ("smog lie") starting around 1959.**
It (PVC) was used on military vehicles to keep debris out of the crancase during WW II (to start with) allowing the engine to breath.
During the 1950s, most of the vehicles on the highway were MFG in the 30s & 40s having worn piston rings. These; when slowing down or traveling downhill, pulled oil past the rings and then smoked a lot afterward.
The PVC systems prevented this and why they were required for a while in some States.
Later; the KV system was added and still exists today. These MUST be in place to pass SMOG along with the rest of the garbage.**
Happy trails.
PS: There's a big discussion of all this (Bench Racing) listed as "BIG BROTHERS SMOG LIE".
** It's escalated to where they (SMOG devices) now cause the vehicle to use much more fuel that necessary, creating more tax revenue for the government. Plus all the BS that goes along with it, fees/controls/inspections. etc.
In California; It's the largest and most well orchestrated, 'consumer fraud' EVER created.
If 'clean air' were the issue, the electric car would NOT have been subverted, three times here, beginning in 1974.
