What causes oil to splatter on the valve cover through the breather cap. Has a fairly new pcv valve run to port on carb.Vent cap on back of block is plugged with a freeze plug.

I'd check and see if the cap's bottom is sealed b/c when I made my 406's home made PCV system, I had to remove all the stuff inside it, then seal all the little holes and finally install a brass 90 hose fitting.

They leak if the holes aren't plugged like you are talking about. And you better have either an intake w/ an oil filler tube and push-on cap or another cap in the front of the drivers side valve cover to complete the air circulation circuit.

pdq67

I have an rpm air gap intake and holley 670 street avenger carb. Breather cap is on the front driver side valve cover. PCV valve is on the pass. side rear and run to big port on carb. Is this proper ventalation? The engine is a 275 hp 327. Engine was made in 1966.I have the correct intake and valve covers that I may put back on the car.

What type of valve covers are you using ? Do they have baffles? If not you can get baffeled rubber gromets that the breather goes into and give that a try.

pcv should be on the drivers side.

Valve covers do have the baffle. They are polished aluminum with the srtaight grooves cut in them. What does it do by moving the pcv valve to the drivers side?


Thanks.

GM made our engines so they end to end and cross breath to help pull the crankcase blow-by vapors out!

That's why on holed valve cover engines, the PCV thing come's from the pass side back and it breath's in through the oil fill cap on the drivers side front. It cross flows..

The old engines are middle front to back flow.. Breath in middle of the intake manifold's oil filler tube and out through the hole by the dizzy.

I would put each diagonally opposite like stock if it's a newer holed valve cover engine that no longer has the road draft tube boss back next to the dizzy to get the cross flow needed to purge the blow-by out b/c if it isn't purged all over, it will eventually sludge your oil.

pdq67

I built a closed PCV system for my '69 just because the vented oil cap was spewing a mist of oil on my aluminum valve cover.

I bought a chrome oil fill cap with a port on it and ran a hose to the bottom of the breather. My PCV is then hooked into the front big port on the bottom of my Edelbrock carburetor. These two hoses are diagonal from one another in orientation.

I have plenty of ventilation for the block and no oil residue on my valve covers.

:hurray:

Thanks. I am going to change my setup and see what happens.

I switched the pcv to the front driver side and the baffle to the rear pass. side and it seems to have worked. No more oil on the valvecover.

Thanks !