GM Vented Oil Cap
09-01-2006, 06:17 PM
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GM Vented Oil Cap What is your take on using the GM vented oil cap as a backup measure to relieving crankcase pressure when under boost? The turbo will be used as a vacuum source.
Both valve covers will be connected in the back. The LS6 valley cover will be used with a catch can leading into the turbo inlet. A check valve will be inline between the valve cover and the intake PCV port.
Is this sufficient or should I use a breather?
I'm also thinking of plugging the passenger's side valve cover in the back and doing what mighty mouse did with the brake booster valve on the driver's side valve cover.
Both valve covers will be connected in the back. The LS6 valley cover will be used with a catch can leading into the turbo inlet. A check valve will be inline between the valve cover and the intake PCV port.
Is this sufficient or should I use a breather?
I'm also thinking of plugging the passenger's side valve cover in the back and doing what mighty mouse did with the brake booster valve on the driver's side valve cover.
09-01-2006, 09:38 PM
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The vented oil cap is the "smog police" stealth version of the breather. If you are exposed to manditory testing or random inspections, it may sneak by, but it is not going to be up to the same relief functionality of the breather.
When in doubt, run the breather.
Rick
When in doubt, run the breather.
Rick
09-02-2006, 10:29 AM
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this is copied from a TSB (Document ID# 1656273) for 2005 GTO's - apparently the PCV systems freeze on these cars
Use a new vented oil fill cap, P/N 12589430. A vented oil fill cap will regulate the crankcase pressure between 15 kPa and 18 kPa. This will prevent the over pressurization of the crankcase under the freezing conditions of the PCV system. Once the PCV system thaws out, the crankcase gases will pass through the PCV system and normal crankcase pressure will be restored.
here's a pic i found in the external engine forum
Use a new vented oil fill cap, P/N 12589430. A vented oil fill cap will regulate the crankcase pressure between 15 kPa and 18 kPa. This will prevent the over pressurization of the crankcase under the freezing conditions of the PCV system. Once the PCV system thaws out, the crankcase gases will pass through the PCV system and normal crankcase pressure will be restored.
here's a pic i found in the external engine forum
09-02-2006, 11:03 AM
#5
hmm so its a pop off valve. as long as it seals under vaccum that would be a great addition to anyone trying to have crankcase vacuum but allow no pressure build up at wot... i made my own for $10. but that one looks much more factory i'm sure...would just have to cut the spring a bit so it opens under any pressure at all...unless it has some geometry problem where it needs pressure to seal.
i boght a pep boys vent with an unscrew top and put a piece of rubber down inside to let it seal under vacuum but vent any pressure.
i boght a pep boys vent with an unscrew top and put a piece of rubber down inside to let it seal under vacuum but vent any pressure.
