MaroonMonsterLS1

Rebuilt my LS1 about 800 miles ago. 230/232 cam, stock rods/pistons, .040 cometic gasket, 799's milled about .028, etc...your basic bit** LS1 for an f body. Nitrous plans for the future, so rings were gapped .028.

for the first 500 or so miles I was nice to it, breaking it in and all. Once I started to lay into the throttle to start tuning with hptuners, I started to notice some smoke in my rearview. Nothing horrible, but not good either.
After a couple WOT rips last week, i had a CLOUD of white (with blue tint) smoke behind me. Clearly I had an issue. Motor kept oil pressure but I was worried it was going to start a fire...so luckily I was less than a mile from home (county blacktop already doing 80 during the pull) so I was able to baby it to my shop.

Get it in the air and determine the rear main is leaking...So I yank out the 4l60e, and find the rear main pushed out of the rear cover. I was able to grab the seal with my fingers and it came right out. First thought said just bad luck, so I grabbed a new seal, put a thin layer of black rtv around the outside edge, and drove it into the cover. All seemed well.

I got it put back together last night, cleaned up all of the oil mess. And started her up. Let it idle for about 20 minutes to get to temp and burn off all of the oily fingerprints from working on it. no leaks.
Drove it to work and back (no WOT rips) and same thing...no drips, no mess. GREAT...I think my problem is solved.

So after work, I lay into it on the way home. Notice a small amount of smoke again...no clouds but something not right. Get it home again...and I have a drip again making a mess on the garage floor.

So...I'm guessing I have a PCV issue? Someone want to give me a little confidence and confirm that...or tell me to look somewhere else? I bought the square speed engineering catch can and have it routed just like the attached photo, Except the red line...I have that capped at the valve cover and then just a filter breather on the IAC line that would normally run to that port on the valve cover. I don't usually get any oil in my catch can...I just get some condensation and that's about it. Which makes me think it's maybe not working right...possibly due to my routing.

Can someone let me know how to change up my PCV so I don't continue to have this issue.

P.s. thanks for staying along for the whole read...I probably wrote way too much for such a simple issue

MaroonMonsterLS1

here's the pcv routing

ddnspider

iTrader: (26)

Was going to guess crankcase pressure. I've always vented both valve covers and never had an issue or noticed a strong oil smell.

themealonwheels

iTrader: (20)

It's been a while since I played with an LS that didn't use the valley for PCV, but isn't there some sort of valve in the driver side rear valve cover port? If so, wouldn't that mean you have two valves in series, one in the VC and one in the line after the catch can?

I like the simplicity of the valley cover option, no external valves. If you're willing to throw a little money and time at the issue, I'd do the valley cover swap as that won't hurt and it could help.

MaroonMonsterLS1

I don't mind spending money if needed...but I have to be 1 of 1000 guys that have a heads/cam f body and don't have the valley cover.
So I'm just trying to track down what I've screwed up.

I'll have to tear it apart and go through the pcv. I'm betting either
A. my new check valve is stuck shut and thus I have no ventilation.
B. my catch can has something blocked in it somewhere (may be my own fault) and I'm not getting any ventilation.

I'm going to try changing up PCV first. I'll post pictures if I notice anything screwed up

cookseyb

Get the LS6 valley cover and throw away the catch can. make sure the fresh air is hooked to the lid some where. Have fun

Majestic9C1

iTrader: (19)

This.. mine has been fine for a few years since I swapped to the LS6 version

98CayenneT/A

2 of 1000, I don't run the valley cover either.
I run my clean air from the rear drivers side valve cover to the throttle body. Then the dirty air front passenger side valve cover to catch can then to the intake. I have my pcv check valve in the line after the catch can going into the intake. Zero issues here.

madmann26

Inspect the rear cover carefully.

I went through the same thing and one of my bolt holes in the cover was cracked. It would only push oil when warmed up and when I leaned on it hard.

Or the seal is in backwards, which coming from you, I doubt.

Hell, get a new rear cover with seal. It’s like $65.

madmann26

For instance,

sjsingle1

iTrader: (1)

your PCV layout does not show the pass side rear valve cover nipple....you have the later style covers with no nipple or ...?

On my stock covers I connect the 2 rear nipples to each other for balance

I also have the LS6 VC....I think it is well worth it

have you thought about installing the new rear seal on the cover with the cover off ...then installing the cover ? I have never done a seal with a cover on.....if you buy a new GM rear cover in has the seal on it

and you are using a GM rear seal right ?

MaroonMonsterLS1

I found my 5/16 barb fitting pcv to be junk. could barely blow through it.

I have another good cover in the pile of parts at the shop, So I'll be dropping the trans again and putting on a new cover with a new seal.
Redo-ing the PCV with a different (larger) valve. Connecting the passenger rear port to the driver rear port for balance.
I also found an oil cap-breather deal sitting on the "why the hell do I have these parts" shelf in the storage shed at the shop, so I'll put that on for ***** and giggles.

Just got a bunch of trans work coming into the shop, so it might be a few weeks before my car even gets to see the shop floor. But that's OK, money coming in is never something to complain about

MaroonMonsterLS1

So, I made a bunch of PCV changes.
I found my small (5/16 barbs on both ends) pcv valve wasn't flowing well at all. I could blow through it but it was like filling up a balloon.
So, I got a new PCV valve (#391), routed it properly to the catch can...Just like the pic above but I connected the passenger side valve cover in also.

I put an oil cap-breather filter setup on too.

I've been driving and ripping on it now for a week every day to work, and I haven't had any more leaks.
I have one TINY drop that I can see every time I park. Never more than one drop.
I'm not sure where it's coming from, might be residual from the first leak, or I might need to seal up the rear main again.
But the PCV seemed to seriously solve the issue I was having.

brandon6.0

iTrader: (32)

U most likely babied it to much after rebuild. U didnt seat the rings in! This needs to be done after a rebuild medium to full throttle hits while varrying throttle.
Engine will produce more power and last longer if performed correctly!

Just vent both valve covers with open breathers. If not it will likely keep blowing rear main seal. Ive see some engines blow the oil dipstick out from blowby!

MaroonMonsterLS1

A. reused rings
B. Dingle-ball hone
C. I definitely worked her hard and seated the rings.
The old pcv was just not working. No place to vent, and a valve that wouldn't flow.

brandon6.0

iTrader: (32)

Well goin by your post it seemed like u did a full rebuild.

Carry on! Good deal finding the fix!