390 PCV problems (*PICS*)

Engine, ignition, fuel, cooling, exhaust

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blue68
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390 PCV problems (*PICS*)

Post by blue68 »

Okay, so my 390 has less than 5000 miles on it, and everything on it is new.... everything. It seems like my PCV hose gets saturated with engine oil and it looks as if oil is getting into my intake thru the carb spacer.. The PCV valve is a new Motorcraft unit. The hose is new as well. If I take the hose off and hold it upright, motor oil drips out of it :eek: . Here's pics of what it looks like:

So what should I do.. because I don't want oil in my intake.

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Thanks ya'll!! :)
kid

Post by kid »

Make sure you have a baffle in the valve cover under the cap. If you do you have way too much blow by.
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Post by blue68 »

I'm not too sure what you mean by baffle, but there's a metal valley lookin thingy in there. It's the first thing you see when you take the cap off. How can I fix this blow by?
kid

Post by kid »

Okay that is the baffle. It prevents oil spray. Run a compression check on the engine and let us know the numbers a compression gauge is not expensive. The PVC does allow oil into the intake that is what it is for. But the oil coming out of the hose when pointed up is too much for normal operation.
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Post by blue68 »

Thanks for the info! I'm not trying to be hard-headed or anything, but why should I run a compression check? That's kind of scary... the motor is brand new and runs as strong as an ox.
kid

Post by kid »

Something is causing a lot of oil breathing. Stuck valve seal, ring or cracked ring and yes it will still run as strong as an OX. I built a race motor that lost all compression on #7 and still ran Low 9s in the quarter.

I never build a motor without a before light off compression check and a 30 minute compression check and a 100 and 500 mile check.
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Post by averagef250 »

Or you can use the super easy method... Just pull the PVC valve out while it's running and put your hand over the hole. If you feel more than a very light puffing you have too much blowby.

You have to seat the rings in a new engine. If you just piddly fart around in it you'll glaze over the cylinder walls and you'll be pulling it down again.
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Post by blue68 »

averagef250 wrote:Or you can use the super easy method... Just pull the PVC valve out while it's running and put your hand over the hole. If you feel more than a very light puffing you have too much blowby.
I pulled the PCV while it was running and I dont even feel anything on my hand when I put it over the hole. I even stuck my finger down in the hole and still didnt feel anything.

I drive the living CRAP out of this engine... WOT every day. Would this have something to do with the extra blow-by?
kid

Post by kid »

yes and if you did it too soon you could have a real headache
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re: 390 PCV problems (*PICS*)

Post by mylifeswork »

You could also use a cylinder leakage tester. If you are not getting much blowby while idling it could be oil is sealing the rings and the compression test may not give accurate results. Of course if that was the case you would see at least one spark plug darker from oil than the rest. The cylinder leakage test puts air pressure into the cylinder to determine how much leakage you have and from where. In this case it should be the rings. You will hear air leaking from the valve covers where the fresh air or pcv cap is. If you hear air out the tailpipe then you have a leaking exhaust valve. If you hear air leakng out the carburetor or air inlet you have a leaking intake valve. The cylinder being tested must be at Top Dead Center on its compression stroke to be accurate.
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Re: re: 390 PCV problems (*PICS*)

Post by blue68 »

mylifeswork wrote:You could also use a cylinder leakage tester. If you are not getting much blowby while idling it could be oil is sealing the rings and the compression test may not give accurate results. Of course if that was the case you would see at least one spark plug darker from oil than the rest. The cylinder leakage test puts air pressure into the cylinder to determine how much leakage you have and from where. In this case it should be the rings. You will hear air leaking from the valve covers where the fresh air or pcv cap is. If you hear air out the tailpipe then you have a leaking exhaust valve. If you hear air leakng out the carburetor or air inlet you have a leaking intake valve. The cylinder being tested must be at Top Dead Center on its compression stroke to be accurate.
Hmm.. this is very interesting. Whenever the engine is cold and I rev it a little, it has a hissing sound when I let off the gas (coming from the carb area). I don't know if you are familiar with turbochargers or not, but this whooshing sound sounds just like a blow off valve. Whenever it gets warmed up, that whooshing goes away.
kid

Post by kid »

That is air flowing over the choke valve edge. My 250 does it warmed up with the engine drawing so hard at low throttle openings it whistles and nothing is wrong.
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Post by mylifeswork »

Yeah that wouldn't have anything to do with blowby or your oil consumption.
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Post by mylifeswork »

I actually think your hearing the high vacuum signal or extreme low pressure created when you close the throttle.
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re: 390 PCV problems (*PICS*)

Post by cdeal28078 »

I used the wrong pcv on the last 5.0 I built and it would push oil up the dipstick and into the pcv after just a couple minutes of idle.
Not sure about the 2v carb spacers but the 4v carb spacers do not work good with aftermarket gaskets causing vacuum leaks,
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