I've got a '79 F150, SWB, 4WD w/ the 300 6. It seems to run OK - get's me around, does my hauling etc. It blows oil into the air cleaner fouls the air filter and makes a mess. I've been told that the compression rings are leaking but the oil control rings are working since it doesn't smoke and the plugs all look good. I replaced the PCV valve hoping that would solve the problem but there was no change. My home remedy for this problem was to splice in a hose from the PCV valve hose to the hose that runs from the breather to the air cleaner. That gave me vacuum in the breather line so that the blowby all goes into the carb base and not the air cleaner.

The problem now is that I can't get a good idle. The modification of the breather system must mess up the fuel mix. I've got a rebuilt Carter single barrel on the engine. The idle varies and the engine is slow to return to idle at a stop sign, etc.

Wondering if there's a better solution to the oil in the air cleaner problem. I'm trying to avoid an engine rebuild for awhile but also want the truck to run better than it is now.

Any suggestions? Thanks in advance for your help.

 

The problem you have is either a bad pcv valve or worn rings allowing excessive blow-by. There is a larger capacity pcv valve available for older engines but it sounds as if your problem is worse than that. The idling problems are mostly likely related to ring and valve wear. Put your pcv plumbing back as per stock for best carb. performance and use a little heavier single wt. oil. Plan on a rebuild soon.

TomC

 

My 300-6 had the same problem. The PCV valve was replaced to no effect. The problem ended up being that the fitting into the intake manifold was plugged. I removed the intake in order to drill out the fitting and this fixed the problem. If you have a new PCV valve, you can check the system by removing the breather line from the fitting on the air cleaner. Put a card over this line and there should be enough vaccume to hold it in place with the engine at idle. If there is little or no vaccume check the fitting to the intake.

 

bubba, if I'm understanding you post right you've created a vacuum leak by splicing into the PCV hose, Put it back like it belongs and see if it will run OK then. Check your PCV system like mentioned above. If its OK your compression are bad.I have heard of people spraying carb cleaner into the PCV valve hose with the motor running to clean it up inside.

 

i had a 390 break no6. compression rings and had to plug off the pcv,plug off the dipstick tube with a peice of hose and a bolt.it was a mess but it ran and drove for8months after that it even blew the front rail gasket out of the intake and filled the alternator full of oil and kept on charging the old truck always smelled funny like melting iron,ahh good ol fords!

 

>I have the same prob. but with a $55 k&n air filter that i dont want clogged

 

>I've got a '79 F150, SWB, 4WD
>w/ the 300 6. It seems
>to run OK - get's me
>around, does my hauling etc. It
>blows oil into the air cleaner
>fouls the air filter and makes
>a mess. I've been told that
>the compression rings are leaking but
>the oil control rings are working
>since it doesn't smoke and the
>plugs all look good. I replaced
>the PCV valve hoping that would
>solve the problem but there was
>no change. My home remedy for
>this problem was to splice in
>a hose from the PCV valve
>hose to the hose that runs
>from the breather to the air
>cleaner. That gave me vacuum in
>the breather line so that the
>blowby all goes into the carb
>base and not the air cleaner.
>
>The problem now is that I can't
>get a good idle. The modification
>of the breather system must mess
>up the fuel mix. I've got
>a rebuilt Carter single barrel on
>the engine. The idle varies and
>the engine is slow to return
>to idle at a stop sign,
>etc.
>Wondering if there's a better solution to
>the oil in the air cleaner
>problem. I'm trying to avoid an
>engine rebuild for awhile but also
>want the truck to run better
>than it is now.
>Any suggestions? Thanks in advance for your
>help.

The PCV valve will not stop oil from passing by it. (And getting to your air filter) One thing that you might try is an oil shield under your valve cover or removing the PCV valve all together and using a valve cover "breather" in its place. You could also relocate the vaccum source for your PCV to the carb base plate. (if your carb has that port that is) Just a thought.

Candyman