hotparts

Hi guys,

i don`t understand why everybody lets the stock crankcase cover breather for blown cars. Is this really enough also for big blower engines (LS2 402 CI) with about 20-23 psi boost and many laps at the racetrack?

I only changed the ventilation at the valve covers. I put a dash 10 in each valve cover and from both valve covers a line to one catch can with a breather and a line back to the cold air intake.

I use the high katech valve covers with no wash plates and under higher boost there comes a lot of oil out from the two breather lines in the covers.

Is it because of the small crank case ventilation or is it normal without wash plates? I connected the crank case line to a seperate catch can. It is always try. Should i messure the crank case pressure under boost and how much should it have?

Is it from my heads or oilpump:
I veha the 225 AFR heads and about 600 kpa oilpressure under high boost and rpm.

Thank you for helping:thumbs:

ajrothm

We made these baffle plates for my Katechs..


-10 males for breathers


We run two -10 lines(one from each cover) to the rear of the car where we have a vented catch can.

Its not running yet so I can't attest to how well the baffles work but you need something in there for sure.

hotparts

Thank you for the picts. My adapters are at the front so maybe there comes a lot more oil from the chanels there.

But what do you think about the crank case vent. The stock LS2 is so small, i always think the valve covers get too much pressure becuse of the small crank case line?

ajrothm

I am using an LS6 valley cover that has the vent. More then likely I will run that vent as well to a seperate catch can...

I would hope venting the valve covers with two -10s would be plenty of ventilation. I would say if you are still pushing oil out of the rear main or the dipstick out, you probably have too much blow by the rings....(which is common on LS motors)

You are going to have to have some kind of baffle in your covers though or you will sling oil right out of those -10s... Those are pretty good size holes and a direction shot off of the rockers....especially once the crank case is pressurized.

Turbo2L

iTrader: (1)

You can put weld a baffle tab on the back side of the -an fitting and it will help with oil carryover. This technique worked well on my DSM over 30psi. YMMV.

rotary1307cc

iTrader: (5)

Here is what i welded as a baffle under mine. -12 to each cover

stevieturbo

You must use a baffle plate of some sort.

Ive breathers on my rocker covers and the valley cover. I dont get much oil from them, but do get lots of condensation.

hotparts

But is the stock LS2 valley cover enough vent from the opening size?

Should i messure the crank case pressure under boost and how much should it have?