Crank case vent ?
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Senior User
Joined: May 2005
Posts: 124
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From: Pt. Orchard, WA.
Crank case vent ?
I have a 1964 merc. 390 in my 55 F-100 there is a metal tube under it that lets out a little smoky "exhaust" is there any way to redirect this back into the motor to cut down on the fumes when idling at the stop light or moving slow
FTE Leadership Emeritus
Joined: Jul 2002
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From: Long Island USA
Switch to a PCV system.
You're getting a little blow-by (past the rings) and it comes right out that vent. A little blow-by is OK.
You can get a pair of valve covers from the late 60's or even from a '70's pickup truck, a carb spacer that gets you the PCV vacuum hookup and hook everything up.
Problem is, your carb is probably tuned to NOT have the PCV. The PCV will put more air into the system (like a vacuum leak) and ruin the way it runs now. You'd have to re-tune to get it running right again.
Others will be along momentarily to give even MORE answers
You're getting a little blow-by (past the rings) and it comes right out that vent. A little blow-by is OK.
You can get a pair of valve covers from the late 60's or even from a '70's pickup truck, a carb spacer that gets you the PCV vacuum hookup and hook everything up.
Problem is, your carb is probably tuned to NOT have the PCV. The PCV will put more air into the system (like a vacuum leak) and ruin the way it runs now. You'd have to re-tune to get it running right again.
Others will be along momentarily to give even MORE answers
New User
Joined: Mar 2006
Posts: 16
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I recently converted my 352 from the stock road draft tube set-up, to a PCV system the way krewat described to you. You'll need to find something suitable to plug the hole where the draft tube originates, and get an oil filler cap that SEALS against the filler neck.
After-market valve covers are also available on e-bay for about $20 that have the baffled port on them for PCV and breather hook-up.
Unless you have easy access to a vacuum port on the intake manifold, you'll need a carb spacer with one on it. And what krewat said about readjusting your carb is a possibility, but I did not have to adjust anything on mine.
After-market valve covers are also available on e-bay for about $20 that have the baffled port on them for PCV and breather hook-up.
Unless you have easy access to a vacuum port on the intake manifold, you'll need a carb spacer with one on it. And what krewat said about readjusting your carb is a possibility, but I did not have to adjust anything on mine.
Posting Guru
Joined: Jul 2003
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From: Colville, Washington
When you convert to the PCV you need a breather type oil filler cap on the opposite valve cover, preferably. The PCV will pull oil fumes out of the engine and the crankcase will need a source of clean air to replace it. If you seal the oil filler it will cause the whole PCV system to malfunction.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
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From: Long Island USA
Originally Posted by Putt
When you convert to the PCV you need a breather type oil filler cap on the opposite valve cover, preferably. The PCV will pull oil fumes out of the engine and the crankcase will need a source of clean air to replace it. If you seal the oil filler it will cause the whole PCV system to malfunction.
New User
Joined: Mar 2006
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If you use the old oil filler cap, which does NOT seal, you will suck unfiltered air through it and into the engine. Either use a cap on the filler neck that seals around the neck and also has a filtered breather in it, or use a filtered breather in a baffled port on the opposite valve cover, which will then require you to seal the filler neck. Regardless, you don't want to introduce unfiltered air into the engine.
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Posting Guru
Joined: Jul 2003
Posts: 2,232
Likes: 1
From: Colville, Washington
foradrive-my bad!! I read that as using a sealed off type oil filler.
You and I are on the same page, just different terminology!!!
You and I are on the same page, just different terminology!!!
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Joined: Oct 2004
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From: Central Oregon
My PVC system uses the port on the back of the intake with a inline valve hooked to the carb base plate. The oil tube goes into the intake witha sealed cap with a nipple, hose going to the air cleaner. The system is a stock PVC system off a 64 Galaxie. I used this type of system because my truck has a set of 64 427 valve covers that has no holes for putting in oil or a PVC.
