SB Chevy Oil blow-by from the front filler tube

OK, here it is. I have a 1968 327 that is stock (As far as i know). I had both heads rebuilt and installed by a shop. I have an Edelbrock RPM intake w/filler tube and 600 cfm electric choke carb (Also gone through). I am running PCV (Zoop Bilit type) on both valve covers (60's Edelbrock finned covers with provisions). I also have a pair of AC Delco I'm not using (Is there a difference?). the driver's side is going to the base of the carb and the p***enger side to the base of the air filter. What's causing oil to seep out from the filler tube with a breather cap (I have stock cap and the chrome aftermarket, no difference). Any ideas. This has never happened prior to the rebuilt heads.

Ken

 

sure you didn't just crack a ring sounds like blow by.any oil coming out of the dipstick tube or other places?

 

Usually oil out the breather is a sign of to much pressure building up in the crankcase generally caused by to much blow by. If you have a leakdown tester that's the best way to check. A problem with the pcv system could also be the problem. With the engine running pull the pcv valve out of the drivers side valve cover and stick your finger over the end-should feel a strong vacuum. If not check the valve and the vacuum source at the carb. Also the way you have it set up the hose to the p***enger side isn't really doing anything. If you're going to run that hose to the base of the aircleaner it should just have an unrestricted fitting, not a pcv valve. Normal air flow in a pcv system is for air to flow from the air cleaner into the valve cover on one side to replace the air being pulled out of the engine and into the intake by the vacuum at the pcv valve. Putting a pcv valve, which is really just a one way valve, in the air supply side will stop air from flowing from the air cleaner. Don't believe me? Pull the hose off the air cleaner and try blowing through it. Your setup it should be pulling the air in through the breather on the filler tube so if you want a pcv valve on both valve covers I would just use a "T" fitting to connect both to the base of the carb. One other possibility, I think there should be a baffle at the bottom of the oil filler tube to stop oil from slashing up the tube, maybe it got misplaced when the manifold was off, I'm sure there's somebody here that will know for sure on that.

 

BigDog, Yes you're right. No oil leaks anywhere else. I think I need to re-do my set-up. I spoke to the machinist who rebuilt the Heads and said the same thing. I think I'm on the right track. I'll also search for that piece that was here awhile back about PCV set-up. If anybody else has more to suggest? Please do so and Thanks.

Viva La HAMB

ken

 

I could be wrong but didn't the early 327 have a road draft tube and a baffled cannister inside the valley ?