jsobotka5

I am new to this website, but frequent it quite often due to my recent LS engine build. Let me start with a quick background of my build. I have a brand new carbureted 408 ci engine which was built by a local race shop. It has an aftermarket valley cover and kateck valve covers. The motor was ran on the dyno and produced over 600 hp. I know this topic has been beaten to death on here but I did not have much luck finding what I was looking for. I was unsure of how to run my breather setup because I did not want anything on my valve covers. Wanted to go with a clean look under the hood. I welded a -10 fitting in the rear of the valley cover and run a -10 hose to a catch can mounted to the radiator support with a breath on top. I took the car out for the first time and noticed that the breather on the catch can was boiling out oil after driving for less that 10 minutes. What would cause this excessive amount of oil to reach the catch can? On my old big block I had a breather on the drivers side valve cover and a breather with a pcv valve on the passenger side that attached to the vacuum port on the back of the carb. Will I need to go back to this or are there other options I can try?

Tainted

iTrader: (9)

do you have a crossover tube to each valve cover so that both sides can vent and equalize?

jsobotka5

no sir, no crossover tube. just the line running to the catch can

Iam Broke

Modern rocker covers are baffled so you pull air, not oil in excessive amounts. I suspect you are sucking oil up the tube from the valley cover port.

Where are you letting air into the crankcase if you are drawing through the catch can via vacuum?

To ventilate the entire engine, I draw filtered air from the MAF tube into the bank 2 rocker cover. out the bank 1 cover to the catch can. Catch can to vac port on my SC above the rotors. Checked breather on bank 2 rocker cover is just insurance to keep from over pressurizing the crankcase under boost. I know you are NA, but just an example.

Tainted

iTrader: (9)

I'd highly recommend running a crossover tube and a breather to let air in and the catch can.

jsobotka5

I have nothing else on the engine as far as valve cover breather or vacuum line hooked to the intake / carb. Just the line running from the valley cover to the catch can. That line does not have a pcv valve in it either.

jsobotka5

so your saying run a line between both valve covers with a breather mounted in it. I have seen that on the CT525 race engines. I believe KRC Power Steering makes a kit but its just for one valve cover. Goes from front to back with two breathers mounted in line.

Tainted

iTrader: (9)

3/4" tube, tie both valve covers together. Consider maybe getting 2 of the same side valve cover with the oil filler cap and mount a breather in each one and run your catch can.

You're drawing air from both sides and venting it that way. seems the most ideal solution short of a real vacuum pump

ruffneckred

Hi, I read this thread with earnest as my son has an 06 GTO, ls2 6.0ltr. He has oil blowing out of the dipstick until you remove the filler neck. Then you can almost see the exhaust notes... Goat has 33K miles, last 3K are his.

Prior owner put a K&N cold air intake on and as far as I can tell there is a vacuum line from the duct in front of the throttle body that runs from passenger side valve cover. Not sure if it is supposed to have a PCV valve in it at that point? At the back of the driver side valve cover is what appears to be a pcv valve with a hose plug on it. Can some one steer me to how the PCV system is supposed to work?

We are hoping to not have a ring / ring land / hole in piston issue, but there is a miss and passenger side exhaust is weaker.

Thanks in advance for any help I can get.

SAPPER

iTrader: (10)

If hes blowing oil out the dipstick, he has more serious problems than a pcv issue. Sounds like a stuck ring or more serious damage. Hes getting actual compression into the crankcase.

MIGHTYMOUSE

iTrader: (59)

in practice i have found big ports on the valley, especially rear of valley to be about the worst place to vent from, sounds like you found that out too.

the highest points on the engine possible and furthest forward (for forward acceleration) possible, with splash shield preferred.

venting one cover vs. the other or 'balancing' them is a matter of opinion since all the airflow comes from the middle.