Do fabricated valve covers need to be vented?
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From: Bonne Terre, MO
Do fabricated valve covers need to be vented? Recently just put a set on my motor, and just wondering if they need to be vented at all? There are no provisions for one, just wondering what kinda things this may cause if I run them without any ventilation.
You need to vent crankcase pressure somehow. I have a vent on both sides of my engine. Take the valve covers off, bore a hole the size needed, insert grommet and vent filter, reinstall.
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Thread Starter
TECH Resident
iTrader: (3)
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From: Bonne Terre, MO
would the -12 off one side to a catch can, not be enough? The car will see the street, but I have done some reading, and this seems to be the best option, If I need to vent both sides, I will but just wondering if it is necessary.
You don't have to vent both sides, you can if you want to but the engine's pressure is pretty equeal. Only reason I have ever been given to vent both sides, was so the contaminents that are airborn, can leave from both sides of the engine since the heat and fumes rise, having a vent on both sides will help keep all of it out a little better. I can't say how much though.
I had a set of valve covers that had -10 bungs on them, so ran a -10 line, connected the 2 together with a T and then to a breather can like described above. If the bungs weren't already on the valve covers, I would have only put one on, fwiw.
Vac pump, if you keep the vacuum level at a reasonable setting, say 8 to 10 in, would be beneficial.
I had a set of valve covers that had -10 bungs on them, so ran a -10 line, connected the 2 together with a T and then to a breather can like described above. If the bungs weren't already on the valve covers, I would have only put one on, fwiw.
Vac pump, if you keep the vacuum level at a reasonable setting, say 8 to 10 in, would be beneficial.
That is NOT a cut and dry answer. It depends on how much crankcase pressure there is in a given application. An N/A engine with moderate cubes and moderate compression won't create the pressure that big cube, high compression, or power adder engines will. Start with one and go from there. DO NOT however "T" off your hoses into a catch can. Both hoses should have there own entry when using a single catch can.
