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Discussion Starter #1
Hey . My 351c is eating oil and and need to top up after a week of driving .. there is black stains out of the exhaust on the rear pan under the rear bumper ... no oil on the spark plugs and no leaks..where else should I check ? Value stem seals ? Intake manifold sucking oil?
 

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On a cleveland the intake gaskets are are a common failure mode which present as excessive oil consumption especially if you used Fel-Pro print-o-seals.


However before you take it apart do a compression test and a leak down test. Also check the valve guide seals.
 

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Discussion Starter #3
I did use felpro gaskets ..it started consuming oil after a cam change ...I'm using an edelbrock 2v to 4v manifold ... maybe I should use the recommended edelbrock gasket and not the felpro one ?

On a cleveland the intake gaskets are are a common failure mode which present as excessive oil consumption especially if you used Fel-Pro print-o-seals.


However before you take it apart do a compression test and a leak down test. Also check the valve guide seals.
 

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I prefer to use the factory "turkey pan" with a ring of sealant around each intake port. Keeps the hot oil off the bottom of the intake. An oil leak into the intake usually will show on the spark plugs, pull them and see if you have one or two that don't look like the others.

Before you tear anything apart, are you using a valve cover with a proper baffle for the PCV? Oil disappears pretty quickly if it's not baffled.
 

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Discussion Starter #5
Not sure if it's baffled... came with it .. here's a picture .... it has a pvc valve installed ..I got spare ones too

I prefer to use the factory "turkey pan" with a ring of sealant around each intake port. Keeps the hot oil off the bottom of the intake. An oil leak into the intake usually will show on the spark plugs, pull them and see if you have one or two that don't look like the others.

Before you tear anything apart, are you using a valve cover with a proper baffle for the PCV? Oil disappears pretty quickly if it's not baffled.
 

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I see the problem. You air cleaner is on sideways. :)

Those valve covers have separate baffles in them that the user needs to install. Pop the PCV out and stick yer finger in. It will be very obvious if it is installed. You should be able to feel it. You don’t need to take them off to check. Those are the same covers I have on my engine, except mine are older and say Ford Motorsport.
 

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Discussion Starter #9
The value cover is baffled ...changed the pcv valve...hopefully that helps with the oil consumption....what to check on next ?
 

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I did use felpro gaskets ..it started consuming oil after a cam change ...I'm using an edelbrock 2v to 4v manifold ... maybe I should use the recommended edelbrock gasket and not the felpro one ?
Well the fact that it started consuming oil after a cam change tells me it is prolly the intake manifold gaskets, or manifold. Does it smoke after decel and you romp on it? If so I would think valve stem seals and if not it points to the last thing you did. Intake manifold.

After pondering a bit I have another idea. My wife says this is not good, but I'm gonna tell you anyway. You most likely changed the cam for a higher lift, and or added rockers. The valve stems could have been carbon coated and with the higher lift they became damaged by the carboned up valve stems.

Seals are easy to replace without pulling the head or intake. I might check into the valve seals before opening up the engine again. I hate antifreeze and oil.
 

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I’m leaning toward valve guide seals especially on the exhaust valves as they run hotter. If the intake gaskets were leaking I think it would show up on the spark plugs. You said your plugs were clean. Now if the exhaust guide seals were bad, you would be loosing oil here which would never enter the combustion or show up on the plugs.
 

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Discussion Starter #15
i will check the plugs again to eliminate the intake valve gasket leak , is there another way to check?... i started losing oil after a cam change so aye
 

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Those Felpro gaskets split very easy. Torque them to spec and no more. Also you must glue the gasket to the head with a contact cement ( gasgacinch or yellow weatherstrip cement)

If there is a trace of any oil where the manifold meets the head/valve cover area the intake gaskets are split.

Next time I take the intake off I'm going to try either Cometic or SCE gaskets
 

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Discussion Starter #17
im going to try the edelbrock gaskets meant for these performer intakes this time


Those Felpro gaskets split very easy. Torque them to spec and no more. Also you must glue the gasket to the head with a contact cement ( gasgacinch or yellow weatherstrip cement)

If there is a trace of any oil where the manifold meets the head/valve cover area the intake gaskets are split.

Next time I take the intake off I'm going to try either Cometic or SCE gaskets
 

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what compression should i have on each cylinder a mostly stock 351c 2v ?
depends
mine bone stock 120K miles about 130 dry and 145 wet

id just be sure theyre all pretty even. I think 10% differential between cyls is the rule of thumb
 
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