For reasons untold here, i drove 220 miles of highway/city driving WITHOUT the oil filler cap in place.
Result: A little bit of oil had escaped and was smeared over my cam cover and made the firewall behind the cam cover a bit greasy to look at.. That was all.
So if the oil is all over your engine -and gushing out so fast, i doubt it's all due to a defect filler cap.
But replace the cap in all cases. It is only a few $.
Could it be that your 'oil channels' inside the engine are clogged so the oil can't get back into the oilpan. -And therefore overflows from the cam cover?