Why would oil be coming through my PCV valve and getting on my carb around where the hose hooks on? Hose not sealing good enough or what?

:hail: IROC-Z

 

More likely lack of baffles in the valve cover, or excessive ring blow-by.

 

I put a clear plastic fuel filter in the line (thanks vader) so you can monitor just how much oil gets through the aftermarket valve covers witout baffles......plenty.

 

thanks guys. mine have baffles but i guess not good enough. The strange thing is that every time i check the oil, it's full. doesnt smoke or anything. so i guess it isnt hurting anything.

 

You shouldn't be getting oil leaking there. I suspect that 2 things are going on, possibly simultaneously. Neither very harmful, really, but easy to fix and will help keep things clean in the future:

1. The PCV hose itself is old and hardened, possibly cracked. Simple fix- replace it with some commonly available 3/8" vacuum or fuel hose- that's the size that the PCV uses. It's in several pieces with a couple of vacuum T's off of it between the valve and the carb, if memory serves.

2. The PCV port on the front of the carb is plugged up. Happens a lot on older QJets. Oil schmutz and dirt build up in the metal vacuum nipple on the front of the carb. Can clog it up partially or completely. Have at it (gently!!) with a screwdriver and a can of carb cleaner if it's lightly gooped up. If it's really nasty it's best to pull the carb and do it on the bench- you don't want all that crud going into your engine.

 

This is a common problem in Autocross which may be at full throttle, 7,000 RPM one second...then on the brakes under full deceleration the next. Throw in 1.0+ g cornering and transitions and oil control in the Valve covers becomes a major hurdle.

Over the years I have found that the single most important item in the Valve Cover for keeping oil out of the PCV valve and being sucked into the engine is the type of baffle used in the Valve cover. Ever notice that Stock Chevy motors never seem to suck up oil through the PCV? GM designed the baffling system very, very well.

The bafflling is key. Look at a factory GM valve cover and look at the baffling system in the oil\air separator. From the top side you have a horizontal baffle plate . Below that are two angled baffle plates at opposing angles. These type of separators are very efficient at stopping oil vapor, yet flow a ton of air.

Most aftermarket Chrome Valve covers are POS made in Taiwan jobbies. The baffling they use often consists of only some punched louvers or slots cut in a single horizontal plate inside the " chimney". This will easily pass oil vapor. Tall valve covers with this type of baffle can actually be worse than a short or regular height valve cover. The length of the inside baffle assembly is the same...so a tall valve cover actually makes it easier for oil spray and vapor to get underneath the " chimney " and be sucked up into the PCV sysytem.

GM Performance sells a nice series of Stamped Steel valve covers with the proper three baffle plate system. You can get them in Chrome or Crinkle Black. Tall or Short . SOB to add Oil to the car, no factory oil cap like the stockers....but you won't suck up any either. Guaranteed!!! BTW, to solve the oil adding problem, I gutted the baffles from the "Chimney" on the breather side and just use a K&N push in breather. Works fine and adding oil a breaze.

Interestingly enough...sometimes the simplest systems work. Edelbrock Aluminium Valve covers seem to work very well. They employ a fairly simple flat plate that screws on just beneath the Breather\PCV hole. Has some deflectors that are cleverly designed that seem to do the trick very well.

Of course, valve covers with no baffle system at all are just a nightmare for sucking up oil.

 

The valve covers I bought are tall Edelbrock chrome ones. There were cheap though. The problem I speak of here (the oil on the carb) started pretty much instantly after putting on a brand new carb, pcv hose and the valve covers. So, taking this facts into consideration, I believe I need some of those Edelbrock aluminum or GM Performance valve covers with good baffles.

One last Q: until I get the new valve covers, is the oil vapor being sucked into the carb going to hurt anything?

 

Probably not in the short run....as long as it's not consuming too much oil. In the long run of course you can get deposits on pistons and valves forming. Not to mention fouling the plugs. I wouldn't do any really hard driving though. Oil in the combustion chamber can cause pre-ignition.

Edit: And if my memory serves me correctly, I do believe that the Edelbrock Chrome Valve covers do have the cheap punched louver baffles. I know the AC Delco's work well...I've got them on my car and it cured the problem.