bunkerbuster

I recorded a video of my 416 ls3 with no pcv. It is blowing out *a lot* of oil mist out of the front of the passenger side valve cover nipple. Is this abnormal? It also likes to drip oil on the passenger side headers after WOT runs can't tell where it is coming from. When I recorded this video, the mist smelled like straight up gas. Then it smelled more oily after the car warmed up.

https://www.youtube.com/watch?v=MasRacFs2mk

dw456post

I couldn't open the link ----are you running a blower?
You really need a PCV. I had the same problem, but after a good RX catch can and a couple of CFM breathers on the valve covers, problem solved. I have two pass side valve covers. The one on the drivers side is an old LS1 truck valve cover with a plastic baffle built in the VC. I heard the LS3 valve covers were a better design, but I have never seen the underside of one. The LS2 vc's only have a metal cover that lets in a lot of oil. I had some oil blowing out of the dipstick also. The working PCV keeps a lot of the fumes out of the engine bay.

bunkerbuster

Try link again. I edited. It is an ls3 swapped into a 4th gen f body, so the pcv didn't translate, thus the guy before deleted it.

MuhThugga

You need to have a PCV system in place, or else the motor is just going to build up crankcase pressure and vent where ever it can.

dw456post

I don't know why it didn't translate. It should be easy enough to hook up. If he just blocked off the tubes, you can get a GM diagram and make it work.

bunkerbuster

Nothing is blocked except for the nipple on the intake, all hoses disconnected. Oil mist has been getting my engine compartment since. The engine was built for boost. Not sure if that make a difference. Is there a good reliable diagram showing how to plumb an ls3 including a catch can? I just googled, and found 2 conflicting sources.

MuhThugga

The passenger side valve cover nipple is connected to the air intake after the mass airflow sensor. The driver side valve cover nipple is capped.

Then, connect the valley cover nipple to the catch can inlet, and then connect the catch can outlet to the intake manifold nipple.

This is an LS1, but it is the same concept:



The only difference being that the fresh air side is connected at the intake tube instead of at the throttle body.

bunkerbuster

I guess I'm trying to wrap my head around how it works, but by hooking it into the intake... That works like a vacuum right? Essentially drawing out that oil mist. Or am I way off here? Otherwise, what's the point of piping it back into intake?

MuhThugga

The connection at the valve cover draws fresh air into the engine. The connection at the intake manifold acts as a vacuum and pulls the crankcase pressure out. This does draw an oily mist, which is why a lot of people install catch cans on their engines. Some have even gone as far as installing a check valve on the fresh air side to ensure air only travels in one direction.

bunkerbuster

I suppose I have always taken the difference between the L99 and LS3 for granted. Is there a way to distinguish the 2 apart? I bought the TA with the "ls3" already swapped into the TA. Thus, I can't just know by auto vs manual.

DietCoke

iTrader: (18)

You cant run a 4" stroke LS3 without a pcv... lol. You're going to make an oil mess and give up free horsepower.

bunkerbuster

If my valley cover does not have a port, where do I plumb the vacuum from my intake manifold? I see that the fresh air from TB is supposed to go to front passenger side port.

1sick_eg

You can add another vent to the valve covers, or get yourself an ls3 valley cover.

bunkerbuster

Found out it is indeed a ls1 valley cover. Looks like I'll be getting an ls3 valley cover, unless there is a cheaper method for plumbing the vacuum.

MuhThugga

LS1 valley covers don't fit LS3 blocks.

If it doesn't have a nipple on the valley cover, then it is most likely the Gen IV 4.8 truck cover.

redbird555

iTrader: (14)

Why not just do what the l92s do? Run a pcv valve off the passenger side rear cover to the intake and then a clean air line from the tb to the drivers side valve cover. Or use a catch can to clean the air up but still use the same routing. No need to change valley covers and you'd want a catch can anyway with either setup. Only down side is longer hoses

bunkerbuster

Did any not watch the YouTube video I posted earlier in this thread? For some reason, the oil mist does not blow out anywhere else except on the front passenger side vc. What does that say about the nipple on the driver side vc? If they are truly open nipples from vc to open air, then why not blow out there too?

L92 =\= LS3 when it comes to pcv systems. Based on my reading...

redbird555

iTrader: (14)

I watched the video but its hard to tell? It could just be the way its coming through the engine. Everything in the engine is cross vented so if you plug on orifice off the mist will eventually find its way out of the other side. It could just be at that port most of the oil mist finds the easiest way out.

Yes the l92 system is different but the shortblocks are exactly the same except the l92 has valve reliefs in the pistons. There's no reason an l92 pcv system wont work on an ls3. Since you already have the truck valley cover you could just do what I said above and copy the l99 or l92 pcv system. Or spend the extra 110 bucks and get an ls3 valley cover. That is the more expensive option, either way the engine needs a pcv system.

bunkerbuster

I have plumbed the system, can I get a double checking of this before firing up?:

Intake manifold(vacuum)<=(catch can)=>USA driver side valve cover rear nipple

TB(air)<==>USA passenger side front valve cover nipple

USA passenger side rear valve cover nipple is capped

Valley cover nipple does not exist therefore capped.

I may need to add a check valve/emergency vent off the front passenger side nipple. (Is this literally the pcv valve?? )

redbird555

iTrader: (14)

you need a pcv valve between the valve cover and the catch can otherwise it looks ok