PVC valve and crankcase pressure
Thread Starter
Instructor
Joined: Nov 2023
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PVC valve and crankcase pressure
Hi,
When I removed my stock manifold and carburetor I replaced it with an edelbrock 2101 manifold and an edelbrock AVS2 Carb. I am no longer using the stock air cleaner. I have a 10" unit now. The PVC valve is connected to the manifold where they told me to connect it. The other valve cover has a vent hole that connected to the stock air cleaner. Not it has a stand alone vent. I feel like since I did this the car uses to much oil. The car does not leak oil at all. It does not seem to be burning oil. Clear only coming out of the tail pipes. How do I know if I have correct crank pressure? The car has 26k original miles and the compression of all cylinders is normal. Valve stem seats were replaced a year ago because they were 45 years old.
Thanks,
Scott
When I removed my stock manifold and carburetor I replaced it with an edelbrock 2101 manifold and an edelbrock AVS2 Carb. I am no longer using the stock air cleaner. I have a 10" unit now. The PVC valve is connected to the manifold where they told me to connect it. The other valve cover has a vent hole that connected to the stock air cleaner. Not it has a stand alone vent. I feel like since I did this the car uses to much oil. The car does not leak oil at all. It does not seem to be burning oil. Clear only coming out of the tail pipes. How do I know if I have correct crank pressure? The car has 26k original miles and the compression of all cylinders is normal. Valve stem seats were replaced a year ago because they were 45 years old.
Thanks,
Scott
Last edited by stosti; Oct 9, 2025 at 11:54 AM. Reason: Accuracy
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2026 Corvette of the Year Finalist - Modified
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It is much more likely that increased oil consumption is due to leaking around an intake port that didn't get sealed properly. The PCV system, all things being equal is working the same as the original setup. Check your plugs and see if you have oil fouling to try and pinpoint the location.
Instructor
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2026 Corvette of the Year Finalist - Modified
2025 Restomod of the Year
Instructor
Joined: Nov 2023
Posts: 136
Likes: 174
2026 Corvette of the Year Finalist - Modified
2025 Restomod of the Year
It is not uncommon for an aftermarket manifold to have some mismatch to the head ports, especially if the heads have been milled at some time in their life.
Safety Car
Joined: May 2001
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From: Fairfax Virginia
A leaky intake manifold could pull oil from the crankcase and burn it. It happens more often when the intake is removed and replaced improperly.
It happens when the RTV used to seal the intake to the block breaks free and allows a leak to occur. I have seen people pulling and tugging at the RTV on the China Wall and this can cause the vacuum leak to occur.
The oil is pulled into the combustion process and it gets burned up. This will cause oil consumption at a slow rate and will leave your garage floor clean as a whistle.
It happens when the RTV used to seal the intake to the block breaks free and allows a leak to occur. I have seen people pulling and tugging at the RTV on the China Wall and this can cause the vacuum leak to occur.
The oil is pulled into the combustion process and it gets burned up. This will cause oil consumption at a slow rate and will leave your garage floor clean as a whistle.
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Le Mans Master
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From: Hermosa
Take a look inside the PCV hose that goes to the manifold first. If there is oil in that hose the PCV may be your source of oil.
That may indicate inadequate baffling inside the valve cover.
That may indicate inadequate baffling inside the valve cover.
