pcv
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From: Southbound
Cruise-In II Veteran
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Joined: Jan 2006
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From: Crossville TN
The PCV valve output is oil vapors from the crankcase of your engine. If you have a fuel vapor canister and it is "T"-ed into the PCV output hose, then both oil and fuel vapors get fed into the baseplate of the carb.
You can tie that PCV output into the front or back of the carb's baseplate, BUT (as mentioned above) if you also have power brakes and they are fed from the rear of the carb baseplate, you run the risk of oil/fuel vapors getting into the power brake diaphragm and having it deteriorate from those fumes. So, while that hose arrangement may "work", it is not such a good idea to tie the PCV output and power brake vacuum supply hose together.
You can tie that PCV output into the front or back of the carb's baseplate, BUT (as mentioned above) if you also have power brakes and they are fed from the rear of the carb baseplate, you run the risk of oil/fuel vapors getting into the power brake diaphragm and having it deteriorate from those fumes. So, while that hose arrangement may "work", it is not such a good idea to tie the PCV output and power brake vacuum supply hose together.
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3rd Gear
Joined: Nov 2012
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pcv valve hose
My power brake booster hose is tied in to a plug on the hi-rise aluminum intake leaving only the pcv hose on the back of carb.Will this make me lose some vacuum to ohter things like my headlights?Is it bad to have oil from the pcv getting into my carb?
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Joined: Mar 2006
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From: Florida
It all depends what carb you have.
If it's a qjet, then any pcv connection (3/8" tube) will be at the front.
If it's a Holley, some are near the rear.
The important part is that the channels in the baseplate disperse the vapors as evenly as possible to all the cylinders. Check your carb to make sure it does not just go to one cylinder. The brake booster is fine going just to one.
If it's a qjet, then any pcv connection (3/8" tube) will be at the front.
If it's a Holley, some are near the rear.
The important part is that the channels in the baseplate disperse the vapors as evenly as possible to all the cylinders. Check your carb to make sure it does not just go to one cylinder. The brake booster is fine going just to one.
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
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From: Crossville TN
It doesn't matter if the PCV line is connected to the front or to the rear of the carb (at the baseplate). Both are "manifold" vacuum connections and both are large enough to handle the PCV output. But, it is best if the PCV line is the only line at its connection point.