WAHUSKER

iTrader: (4)

Just curious what all you guys have done (that have this issue) to fix it? I've searched but can't find many ideas. Other than putting a breather cap into the oil filler hole, which seems like a weak fix. So I was looking at the motor tonight & wonder if it isn't the PCV tube that runs into the top of the throttle body (IAC area). Thinking when your in boost, that hose is getting pressurized, and MUST be flowing hi-pressure air into the valve cover (easily defeating the catch can vacuum).

Anyway, I've plugged it off to see what happens. I figure on a brand new forged stroker motor setup for boost, it can't be broken ring lands (I've read this is a symtom of that). I'll let you know if it works.....gotta be a way to NOT soak down my show-car engine bay when I race.

Mark

kp

iTrader: (34)

If the hose between the top of the TB (metal 90 degree elbow) is hooked up to the valve cover it will pressurize the crankcase pretty well, that needs to be capped off at the valve cover and the TB.

WAHUSKER

iTrader: (4)

Yep, that's the one I'm talking about. Sounds like I'm on the right track. Thanks kp!

kp

iTrader: (34)

No Problem, also make sure to use an aftermarket check valve for the PCV as well, the PCV wont seal 100% under boost. Wont be as severe as that breather hose but it should still be done.

Also your idle and part throttle trims might get a little wacky after you plug those, I usually just adjust the MAF numbers a little to compensate.

White.Lightning

iTrader: (53)

Is this recommended to do even if the dipstick is NOT blowing out?

Andy

Ed Blown Vert

iTrader: (2)

My TB is capped with the valve cover hose running down to the inlet hat. I also have a check-valve in the pvc line.

kp

iTrader: (34)

Opps, I forget that if you arent running a breather on the valve cover that you have to run the line from the valve cover to the blower inlet, otherwise there will be no place for the crankcase pressure to vent to at WOT

I prefer the breather since oil vapor will tend to get into the inlet but if the motor is in good shape it wont be a problem.

BOOSTAT4500

iTrader: (17)

I ran a -16 line from the oil fill whole down to exhaust like you see on drag cars. Solved all my pressure and oil consumption problems. I was able to ditch the line going to the blower hat and it kept everything much cleaner, plus no more oil traveling through the IC pipes. Just another option.

ddnspider

iTrader: (26)

just thought id throw out my plan for pcv and get some feedback,KP i remember you helping me try to figure it out so thought id see if i got everything.
the front pass cover oil cap get a big screw in breather. the 2 rear ports go to a Jaz catch can with a breather on top.Then cap off the intake and TB.Did i get everything?

kp

iTrader: (34)

Thats how some do it and it works fine.

I still use a PCV though, keeps the oil a little cleaner if you street cruise a lot - maybe

I use the LS6 valley to PCV valve to AMW catch can to check valve to Intake. Then use a breather on each valve cover.

I probably dont need the PCV anymore but I am too lazy to change anything and it works OK for me..

ddnspider

iTrader: (26)

it is a street car...DD really.i hope itll surfice,guess we'll see,what if i put check valves in the hoses off the back of the valve covers.

kp

iTrader: (34)

You dont really need a check valve in those hoses, the way you are doing it just using the JAZ can as a breather, Same as the one in the oil fill hole, just it wont drip on your headers.

The PCV pulls air through the crankcase at idle and any fumes/moisture gets sucked into the intake and burned off. At WOT the PCV is closed (along with the check valve that seals off the intake boost from the crankcase) and then the breathers in the valve covers take over the job of venting excess pressure. Sometimes you will get some oil vapor along with the blowby and thats the idea behind using the catch can off the valve covers.

I use the catch to keep the oil from getting in the intake.

BOOSTAT4500's way of doing it works well at WOT only and pan-e-vac systems dont usually work well at idle/part throttle with a full exhaust. The check valves will flutter a lot with any backpressure and exhaust will end up back up n the crankcase (most of the time anyhow).

There is more then one 'correct' way to do it. Only problem with no PCV is the underhood starts to get that oily smell after a lot of regular driving, some people it doesnt bother but I dont like it, reminds me of old road draft tubed stovebolt 6 in the old 64 chevy I used to drive Naturally if you have a motor with bad ring seal and a ton of blowby its going to get pretty bad at idle but if the motor is sealed well it will probably be just fine..

ddnspider

iTrader: (26)

Would doing it this way cause blowby?Id like to minimize that if possible,ie is there anything else in addition to what i listed that could or should be done to help?

kp

iTrader: (34)

Blowby is the combustion that gets past the rings coupled with the backside of the pistons pumping as well in a small area. Nothing you can do can make it worst or better externally except try to control it with breathers, PCV, vacuum pumps etc.

If you change your oil a lot and dont do a lot of short trips not having a PCV will be fine, if you notice smoke rolling out of the breathers at idle and the car starts smelling like a used oil drum you may want to hook up the PCV The PCV will even help scavenge the oil out of a turbo that doesnt have enough 'downhill' drain at idle sometimes..

ddnspider

iTrader: (26)

hmm interesting.Well i hope itll be ok on my dd,but if not,you maybe getting a pm lol

BOOSTAT4500

iTrader: (17)

I didn't notice any flutter, or pressure at all comeing back up the line, no matter what the throttle position was. My exhaust didn't have much back pressure at all though. ( 3" Y into single 4" dumped at the axle, bullet race muffler ), so that probably helped. Just my .02. Lots of good ways to do it.

kp

iTrader: (34)

It really depend a lot on the cam etc. If you can keep decent velocity running past the nipple stuck in there it wont back up. Its worked for a lot of years

andereck

I think the LS1 is a tough case for ventilation. The crankcase volume is smaller than engines of the past including the oilpan. The valvecovers are very short. Most LSx blocks also don't have any cross bulkhead breathing, and the windows added to the bulkheads on performance blocks are actually patented by GM. I have seen dipsticks pop out of LS1's due to the increased crankcase pressure with relatively low boost. It is difficult to manage and takes some creativity.

As a side note I have had better than expected results with a pan-evac system on other engines incorporating a full exhaust. At idle the breather will actually stick to the palm of your hand. The only trouble is that the airpump check valves will burn out after a fairly short amount of time, like a few thousand miles. I found it necessary to stuff the breathers with scotchbrite or steel wool to help reduce oil pullover and a plastic restrictor in the hose also proved benificial. I think a pan-evac will only really work well on a full length collected header system, but your experiments may prove otherwise.

kp

iTrader: (34)

Honestly the only dipstick I ever blew out on an LS1 was when I broke the ring lands in the old #7 piston using nitrous. I have had 3 different LS1 procharger setups and never popped a dipstick on any of them But yea the LSx diesnt have a lot of room in the crankcase, cant change that easily and the longer the stroke the worst it gets..

I have tried pan-evacs on several street cars with full exhausts. With a big overlap cam it would pulse real bad at the breather and if you held a lit cigarette up to it you could see it blowing out pretty well. Granted these were good 275 degree plus @ .050 roller cams in 470+ inch motors. But they do work, put them over the rocker arm of an unrestricted oiling up top motor and its amazing how much oil they would vacuum up at WOT

The valves dont last long at all even on a race car but its a cheap system that does what its supposed to.

Pro Stock John

iTrader: (34)

I run a filter on each valve cover and that's it.