VCB100 Lock On Breather
2psi Valve Cover Mount Blow Off Valve

2psi High Volume Blow Off Valve

Valve Cover Mounted
Part #VCB100B
In stock - Usually ships in 1-2 Business Days
Only $97.00 ea
Protect your car in the case of a blown head gasket or piston failure by venting your crankcase positive pressure with this 2psi Valve Cover Mounted Blow Off Valve. AN #12 x 3/4 NPT fitting included, upgrade to AN #16 optional.
Qty Options:

No Welding Required!

Made from 6061 Billet Aluminum stock, it is a two piece adjustable valve that relieves pressure in the crankcase due to blown head gaskets or piston failure which can result in lots of air volume bypassed to the engines crankcase. It also protects in the situation where the vacuum pump isn't working due to a thrown belt. The GZ Blow Off Valve PN VCB100B consists of a base with a nylon washer and nut that can be installed in a standard grommet hole in a valve cover or placed in a valley pan and a top that may be removed to replace the spring of Teflon ball inside. The top has an o-ring between it and the base to which is attached for leak free sealing. Once the valve is activated, the blow-by gases are vented through a fitting in the top which may be routed to a catch can or other means of containing fluids in the gases.

A pressure relief valve (blow off valve) is essential for any turbo, blower or nitrous equipped high performance engine with a Vacuum Pump. If for some reason the pump can't keep up with crankcase pressure (like a hole in the piston on a blower car), the blow off valve will safely vent that pressure to a puke tank instead of pushing out a gasket in the engine and getting oil under the tires.


  • 1/2" NPT Outlet
  • 6061 T6 Aluminum Construction
  • Preset to relieve crankcase at 2 psi pressure
  • Fits in 1 1/16" to 1 13/16" (1.0625" to 1.8125") mounting hole
  • Includes AN #12 x 3/4 NPT fitting or upgrade to AN #16 x 3/4 NPT fitting (optional)