when i was doing some routine maitenence on my 85 f-150 a few months ago, i noticed that inside the throttle body was black with oil. i took the upper manifold off and it was black too. i cleaned everything and put it all back together and the truck ran a lot better. now i notice the problem is back, along with the breather tube spitting out oil. is there any way to fix this permanantly? i'm thinking about just running the pcv tube out the bottom of the truck and plugging the hole on the intake it goes to. would that fix it?

 

Did you change your PCV valve?

 

no, when i cleaned the intake the first time, i cleaned it too. i didn't replace it because the haynes manual said that if it rattles when you shake the valve cover, then its good. i shook it and it rattled so i cleaned it and put it back on.

 

In view of the symptom, I would change it anyway. The rattle test just tells you it is not stuck. It may not be closing when it should. They are cheap and it is worth a try.

Other than that, do you have any oil consumption? Possible blowby issues?

 

i will change it. that was what i was thinking. its cheap, so why not. no to the oil comsumption though. my truck has never been bad about that. it does though, have a loud ticking sound coming from under the valve cover. the louder i rev the engine, the louder the ticking. i don't know if that has anything to do with it or if its a seperate problem all together.

 

sounds like a lifter sticking and the valve lash getting out of adjustment.

 

i don't know anything about the valve lash and how it works. can you tell me any possible things i could do to fix it.

 

Let's take it from the top:

you have what sounds like crankcase pressure from your statement that there is oil spitting out of the breather. That is why I asked about the positive crankcase ventilation valve which is there to relieve crankcase pressure in a controlled manner. So that's one item. Crankcase pressure is normal within limits. If it is too great for the pcv system to relieve it, you may have some blowby, or combustion pressure leaking past the rings or a bad piston.

Secondly, you have ticking noise that increases in volume as the engine rpm increases. Taken alone, since it sounds like it is coming from a valve cover, it is reasonable to imagine it would be a sticky or collapsed lifter, or a rocker arm in need of adjustment.

So what type of engine are we talking about here? Assuming it is a pushrod engine, I would say that the valve cover needs to come off, but I would first pull plug wires with the engine running to see if that has any effect on the ticking noise. If there is no change in the ticking noise when you pull the plug wire for the affected cylinder then you need to look for the ticking in the valve train.

Valve lash, is a term used to describe the clearance between the rocker arm and the valve stem. With hydraulic lifters, the most common type, the valve lash should be zero and thus the rocker and valve stem are in constant contact. Therefore there is no ticking sound produced which is common with solid lifter engines.

Some Ford engines have an adjustment on the rocker arm, some do not. But if you want to isolate the ticking noise, and pulling plug wires has no effect, remove the valve cover and start the engine. (Be prepared for some mess from oil, don't rev the engine or it will be a lot worse.) With the engine idling, press on the rocker arms above the push rods one at a time to see if that quiets the ticking noise. If it does, then you have isolated the sound source.

Keep us posted, let us know what you find.

 

the engine is an efi 302. i did try the spark plug thing a while ago. the ticking was still there. i've also tried putting marvels mystery oil in the oil, but nothing happened. i haven't tried the valve cover trick yet. i was planning on rebuilding the engine this summer though. do you think it would run long enough to make it to summer, or does the problem require immediate attention?

 

Anyone would be guessing to answer that without being able to examine the engine.

 

well, i guess i'll try taking the valve cover off and finding the bad cylinder. if it is a sticking lifter, can i just get a longer pushrod or something? i really wouldn't want to tear into the engine for one little thing.