Smokin 390fe
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Smokin 390fe
hey out there! well, been trying to figure out why my fresh supposedly "ready to go" 390fe is smoking. went through all I could think of. Checked all the obvious stuff( Bad intake seal, oil flow restrictors, intake gaskets, ect. Well, took off my heads, thinking head gasket issues,and lo and behold, I got a close look at my valve stem seals. They are new. BUT, they arent sitting at the bottom of the valve stems, every single one is all the way at the top of the valve stem up against the base of the retainer. I personally have never replaced a set, is this normal? I was under the impression that they somehow locked in or were retained at the bottom as to keep the oil out of the guide.Am I mistaken or is this a problem? any ideas?
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Joined: Apr 2009
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From: Stanley, VA
X2, the seals are called "umbrella seals" because that's what they act like. The seal fits snuggly on the valve stem and move up and down with the valve.
There is a type of seal often called "Perfect Circle" style that does "clamp" around the valve guide and doesn't move. This is a positive seal and requires that the top of the guide be machined to fit the seal.
If the engine smokes on start up and then clears up I would suspect worn valve guides. If it smokes while going down the road I would suspect worn rings.
There is a type of seal often called "Perfect Circle" style that does "clamp" around the valve guide and doesn't move. This is a positive seal and requires that the top of the guide be machined to fit the seal.
If the engine smokes on start up and then clears up I would suspect worn valve guides. If it smokes while going down the road I would suspect worn rings.
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Are you using stock valve covers or an aftermarket set? An aftermarket set without baffles can create that situation as well. Too much oil is being drawn into the PCV, after shut-down the oil pools inside the PCV hose. On start-up the pooled oil is pulled into the engine, causing the smoke.
Otherwise, it is usually bad valve stem seals.
Josh
Otherwise, it is usually bad valve stem seals.
Josh
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Joined: Dec 2009
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From: Mississippi
Are you using stock valve covers or an aftermarket set? An aftermarket set without baffles can create that situation as well. Too much oil is being drawn into the PCV, after shut-down the oil pools inside the PCV hose. On start-up the pooled oil is pulled into the engine, causing the smoke.
Otherwise, it is usually bad valve stem seals.
Josh
Otherwise, it is usually bad valve stem seals.
Josh
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Joined: Aug 2001
Posts: 14,441
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I would tend to think a malfunctioning PCV would create smoke all the time, not just start-up.
Stranger things have happened though...
Josh
Stranger things have happened though...
Josh
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