392 crankcase ventailation
Moderators: scottm, TrWaters, 392heminut
392 crankcase ventailation
bouught a 392 that been overhauled but not finished. there is no provision to vent crankcase. engine has hothead valley cover,tunnel ram 2/4 set up &stock valve covers. any ideas?
392 breather
Easiest thing to do is install a breather on one valve cover & drill a hole for a grommet & push in type PCV valve on the other cover, or the oil fill cap.
crankcase ventilation
I have a 392 with the hotheads valley cover and valve covers. I added a 1.25 tube to the valley cover at the front with a K&N breather and i am going to put a fitting in the oil fill plug at the back of the valley cover and use a inline PCV valve this should vent the crankcase. Hotheads also makes breathers that will fit under your intake.
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budmspeeco
- Posts: 133
- Joined: Tue Dec 21, 2004 5:35 pm
- Location: South Houston, Texas
PCV/ breathers
I have seen this mistake countless times. Install a PCV valve on one valve cover and a breather on the other only creates a vacuum leak . The correct method is to install a vent line to go under the air filter base in the area between the filter and the carb inlet. This creates another vacuum source to pull gasses from the crankcase & runs them through the combustion process in the engine. I would/have put a PCV valve on each valve cover rather than a breather / PCV combination. I think the engine will be cleaner and idle better. 
'48 anglia
breathers
The air has to get into the engine,thats through the breather. It goes through the engine to the PCV valve(1 way valve). It then goes up the hose from PCV valve to the fitting on plate between carb& intake(or fitting on carb if Edelbrock carb is used). A PCV valve on each cover would only work if you had the OEM oil fill tube & breather oil cap.
breathers
The breather at the front is in the same postion as the stock breather on a 392 the pcv at the back of the valley would be where the road draft tube would have been on the old V8 engines. The road draft tube created a vent and also sucked the air throught from front to back from a vaccuum created by air passing by the tube while diving. Using the breather with the hose connected to the air cleaner would also draw or vent the crankcase if you had two breathers to allow fresh air in, with one of the two being the breather connected to the air cleaner.