rad_vet

Last week i installed a catch can between the valley cover and the pcv to the intake manifold. After 80 min of track time (4 20 min sessions) there was less than a cup of oil in the catch can. However, the engine went through two quarts of oil. I thought the rings or valve guides were worn out. A compression check showed 205-210 psi in each cylinder and nothing comes out of the oil filler port while revving the engine. I did notice oil was going through the hose from the valve cover to the intake. I am assuming this is how all the oil is being lost.

After reading what others have done on this list, I would like to try the following:

Plug off the ports to the intake manifold, run a hose from each valve cover to the catch can, run a hose from the valley cover to the catch can, and run a drain hose from the catch can to the oil pan. The catch can will vent to atmosphere.

For those who have done this, did you have to drill a hole in the oil pan and thread the hole to connect a barb fitting and hose or is there a plug on the pan or block that can be used? Will this system vent the crank case properly without suction from the intake manifold?

Thanks.

Tony

trackboss

It would be a lot easier to just dump the catch can oil back into the valve cover at the end of the day if there is any in there.
The system will vent properly. No suction is needed from the intake. That is there for smog purposes from the factory. As long as you plug the intake barbs when venting to the atmosphere, as you described, you are good to go. Some vent to the atmosphere and still run hoses to the intake which does nothing but create a small vacuum leak. Unmetered air gets in the motor and can possibly cause a lean condition.

kmagvette

I have the opposite "problem". I installed a catch can, flogged the crap out of my car (Watkins Glen) and after two days I do not even have a hint of oil in the catch can. I fill a full 1 quart over and my engine does not burn oil - that is not a complaint. I typically go six track days between changes.

I was expecting to at least see some sign of oil in the catch can; I even connected it properly.

Timz06

From my experience, if you need catch cans etc, your engine is probably not built properly or is damaged.

Tim

ErnieN85

it's blowby which causes the problem and there will be some no matter what! Hot oil is thinner so if your temps are high and your running hard that is when the problem occurs. Stock PCV system is good enough! just get an engine oil cooler so the oil isn't hot and vaporizing easier.

ZR1 MK

The pcv suction gets reduced with increased throttle and is zero at full throttle due to vacuum reduction. After that, its pressure forced only.

To improve breathing and reduce crankcase vapor pressure (less pressure on the rings, seals and gaskets), I installed a 5/8" hose with a ball valve, and a one way valve from the valley area to a breather tank/filter to atmosphere. Its gets opened for track use only.

igo380

Where did you get the one way valve? I havent been able to find one for my set up.

Thanks

Jim

ZR1 MK

PCV valves are one way valves, but if you want to use large hose for increased flow, Moroso has a valve for 5/8" hose.
http://www.summitracing.com/parts/MOR-97800/

RX-Ben

What year is your car? Certain years like to drink oil due to the rings.

I disagree with the comment regarding no need for catch cans....properly constructed cans filter the crank air, which has oil in it due to the action of the crank. If you are getting nothing in your catch can you may be running the older style valley cover or have a weak vacuum pull (restriction in the can or lines) or not running a baffled can or not having the can cool enough to precipitate out the oil. You should get something. I would be more concerned with totally a totally dry can than with getting some oil in the can.
In my oil-drinking 2001 (w/the problematic rings), w/LS6 valley cover, at the track the can doesn't pick up much, but I suspect the rings are letting a bit of oil by during high rpm/low load conditions (downshifting while braking) due to the rate of oil consumption.

trackboss

I had some aftermarket catch cans on my car and was not getting much oil in them at all, but my intake was always very wet with oil. I suspected that the vacuum from the engine was still pulling the oil. I then made my own can and took the whole vacuum out of the equation which resulted in a catch can with several ounces of oil in it after a session on track.
In other threads I've discussed the oiling issues with these motors. IMO opinion, basically a deep skirt block combined with very shallow wet sump oil pan and high cornering forces result in too much oil staying up in the heads. The crank whips up the oil and makes it very difficult for the oil up high in the motor to drain down where it needs to go. A crank scraper would make a huge difference and furthermore a dry sump would completely solve the issue.

RX-Ben

I looked a bit for a crank scraper but did not see any offered - does anyone know of any?

Webz

I'm running an ISHIHARA-JOHNSON crank scrapper and windage tray on my LS3. My PCV is plumbed into a vented catch can eliminating the return into the intake. I have had the compression checked on the car and it is in great shape. I have an accusump and am seeing oil pressures in excess of 65 PSI when idling at 200 F(oil) and +35 PSI @ 290F. With all of that I am still getting about 2/3 quart of oil in the catch can over a day of track time.

http://www.crank-scrapers.com/Chevrolet_LS.html

RX-Ben

Thanks for that link - I came across it a while ago but since misplaced it (I should've searched for "LS crank scraper" instead of LS1). Do you run the teflon version?