oil pressure/ ventiltion issues

I am having an issue with to much pressure building up in my valve covers. It has a breather in one valve cover and a pcv in the other. pressure started building up and dripping oil out of the breather. I tried T- ing off my vacuum source and running a pcv to both valve covers and it is blowing the pcv out of the side where the breather was now. The engine is a chevy 350 with a slightly over stock cam, more for sound I guess. Can any one point me to an already open thread or give me some ideas?

Thanks Chandler

 

you may be experiencing too much blowby. have you done a compression check?

 

1 Verify vacuum at PCV
2 Check compression
3 Rebuild motor.

If you have vacuum at the PCV and it is not clogged up, and it still does not ventilate enough to stop the oil from coming out the brather, you've got problems.

 

Sounds like excessive blowby from worn rings. Compression test will tell easy enough.

 

you might wana try a cylinder leakdown test, compression tests dont allways find leakby from the rings. but i wouldnt do that test unless the compression test didnt find any obvious problems.

 

Does the valve coverhave a baffle plate in the cover to keep the oil from splashing directly into the breather ??? I've seen this happen way to many times. Most people don't install those square steel plates that come with the covers. Just make sure there is a sheild to keep the oil out of the breather. If you don't have the steel plates you can fab them up fairly easily >>>>.

 

Any pics of the steel plates? I am having a similar problem.

 

Just cut a piece of sheet metal to fit,there should be some bungs under the vc to bolt it to.

 

I had a set of Mooneyes no-name finned valve covers. I had them install breathers to each valve cover (option). There wasn't a splash guard, but they stuffed foam inside the breathers. Works fine for me.

 

Excessive blowby can come from bad valve guides, too.

During the '07 season, in less than 5000 miles, I went through SEVEN AND A HALF GALLONS of oil in my hemi after having a valve job done on my heads. My machinist let his son (a Chevy guy) do the work.

I took the heads back last winter and had them done right (at his cost) and the oil consumption problem went away, totally.

 

I am also having that same problem.

There is no baffle plate in the valve covers. I do not think there is enough room in there with the roller rockers. it is tight.


so I am also looking for a solution.

 

well i might as well get inline . model A banger , 7-1 head , 125# compression in ea hole . around town no problems ,
but at 60mph for say 100 miles & it seems to push oil out the rear seal . put a nipple in my intake manifold & plumed it to my breather tube (closed system) . works well but now no indicated oil pressure . any ideas appreciated ...... steve

 

It seems from what I've read that if you put vacuum to the crankcase the oil pressure will be reduced...If you have more vacuum than oil press then that is why gauge reads zero...Sounds like you need to fix the rear seal..

 

I have a set of baffles I cut out of old Chevy valve covers. If someone wants them.

 

Trust me on this you need baffles!!! If you are running true roller rockers, Not just roller tip, Then put in a spacer plate under the valve cover. Pressure in the crankcase comes from pistons moving up and down. On the down stroke the piston, with it's concave area under the dome, acting like a big toilet plunger pushing X amount of air back into the crankcase.

 

But for every piston moving down in the bore pushing air into the crankcase, there's another piston moving UP in another bore at the same rate INCREASING the air volume in the crankcase. Theoretically, at least, there should be no change of pressure in the crankcase because the volume of the crankcase remains constant. If there's pressure in the crankcase, and there usually is to at least some slight degree, it's due to a piston not sealing properly or an increase in engine temperature heating and expanding the air in the crankcase.