Hey guys. This keeps happening....the passenger side valve cover gets gunked up after a few weeks after I clean it. It's gunked all around the oil fill cap with black stuff. I pulled off the hose that goes from the TB to the valve cover, and it's all dry inside - no oil at all. Any ideas? I was going to pull off the PCV valve and see if its clogged, but there are these lines in the way and I don't know what they do.

 

after you confirm that your PCV system is operating properly, you may want to consider a crank case breather... depending on how old your motor is you may be getting more blowby than normal, and the pcv system only works its best at idle (where there is the most vacume....)

a crank case breather will prevent positive pressure from being built up inside the crank case.....

 

I came across an old post that Fred (Injuneer) made, and I took the oil fill cap off, and let the engine idle. There was no sucking or pushing of air...so wouldn't this indicate that the amount of blow-by is normal?

 

Also, I tried to take off the PCV valve to see if its clogged up, but there are a few lines in the way. I found a picture of it on shoebox's site, but his shows no lines in the way.

 

you need to rev the engine up.... bring it up too about 3k and hold it and re conduct this test....

if its starts pouring smoke out the oil fill cap, then you have a problem... if not... everything should be fine.....

a good operating pcv system should baisically suck your hand to the oil fill.... untill you hit WOT and run out of vacume....

a crank case breather will allow fresh cool air to flow through the engine, and during WOT blasts when vacume is at its lowest, it will prevent the buildup of positive pressure in the crank case....

this is what causes some oil leaks...

 

http://images.cardomain.com/member_i...1_121_full.jpg
http://images.cardomain.com/member_i...1_122_full.jpg

 

I got the PCV valve off, shook it and it rattled so I guess that means it's good. Would it be possible for the oil to be coming through the valve cover bolts?

 

I checked the bolts, and they're tight. Can't anyone help me?

 

A breather is going to allow unmetered air into the engine throwing off your air/fuel ratio.

 

lol..... thats funny... great questions, from all, great answers from all, but you guys let yourselves get nowhere with these closed minds.

what is everyone concerned about... going fast... and that would be WOT... at WOT there is no vaccume...(manifold pressure is equalized to atmospheric "0psig or 14.7 psia") so how can that allow a ton , if any of un metered air into the engine, in an amount large enough to make the tiniest change to air fuel, that the computer couldnt correct from using O2mv....

knowing this information now... if the blowby in the crank case was great enough, couldnt it cause a positive pressure inside the crank case.....? now we know that manifold vacume at WOT is 0, with that in mind, how do we remove the crank case pressure...?

a couple of ways...

breather, and allow it too escpae naturally untill vacume returns.

or a crank case evacuation system, which is baisically a check valve welded into the the exhaust system downstream, and uses the negative pressure created by the exhaust as it passes through the tube, too pull out the crank case vapors.....

and a vacume pump... a pump that pulls a vacume on the crank case.

 

At WOT, the engine runs in open loop, therefore your O2 sensors won't be adjusting your AFR.

Try an experiment, with your engine running, unscrew your oil filler neck from the valve cover...notice the change in idle.

 

your the one who said unmetered air affects Air fuel ratio.

so at WOT, is it unmetered or metered.

I'll just enjoy my engine with the crank case breather... the unmetered air and my screwed up air fuels....

maybe well meet up at the track one day....