Generation III External Engine LS1 | LS6 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

Trying to relieve crankcase pressure...

Thread Tools
 
Search this Thread
 
Old Aug 14, 2013 | 03:27 PM
  #1  
S1dc_Drifter's Avatar
Thread Starter
Teching In
iTrader: (2)
 
Joined: Jul 2011
Posts: 27
Likes: 0
Default Trying to relieve crankcase pressure...

I am getting some blow-by at high rpm. I have a breather in place of the oil cap and a catch can with PCV deleted. I have oil coming out of the breather under heavy load. The motor is brand new with about 200km on it, it is used in a drift car so it sees high rpm majority of the time.

I spoke to my builder and he said I need to vent some more crank case pressure. I have a few options to choose from:

1) Moroso evac system and use my current catch can (I have open headers)

2) Ls6 Valley Cover with catch can and get rid of oil cap breather

I wanted to get some opinions, I have heard of people continuing to get blow-by even after the ls6 valley cover swap. Also I have heard mixed reviews about the evac system.

Basically I need to vent the most amount of crank case pressure to relieve small oil leaks and blow-by without spending 500-1000 on a vacuum pump.

Thanks guys!
Reply
Old Aug 15, 2013 | 10:03 AM
  #2  
01ssreda4's Avatar
TECH Senior Member
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (96)
 
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Default

Why do you have so much blowby?
Reply
Old Aug 15, 2013 | 01:12 PM
  #3  
S1dc_Drifter's Avatar
Thread Starter
Teching In
iTrader: (2)
 
Joined: Jul 2011
Posts: 27
Likes: 0
Default

Originally Posted by 01ssreda4
Why do you have so much blowby?
I am not quite sure. I will being doing a leak down test shortly. I have heard that these engines have blow by issues. The reason its spraying is because of the breather. The dip stick pops up a little bit also.

for people to run these evac and vacuum pumps I can't be the only one suffering from this.

I am just trying to get opinions on the best way to remedy the issue.
Reply
Old Aug 17, 2013 | 12:28 AM
  #4  
01ssreda4's Avatar
TECH Senior Member
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (96)
 
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Default

Brand new engine............sure the rings have seated?
Reply
Old Aug 17, 2013 | 09:07 AM
  #5  
Grr's Avatar
Grr
TECH Fanatic
20 Year Member
iTrader: (2)
 
Joined: Mar 2005
Posts: 1,363
Likes: 1
From: Fargo ND
Default

use the catch can and hook that PCV back up, its foolproof and you shouldn't get any oil in the intake
Reply
Old Aug 17, 2013 | 02:38 PM
  #6  
Trboboost91's Avatar
Teching In
 
Joined: Aug 2011
Posts: 11
Likes: 0
Default

Ill just add to this in hopes of more help without starting a new thread.
I have a roadrace miata that is ls1 powered and I guess I has the breather/pcv system hooked up completely wrong or I have a lot of blowby/crankcase pressure as it pushes oil right past my valve cover gasket on the pass side but not the drivers side (wierd?) when used at high rpm/load.
Looking for the best remedy for this. Possibly just a factory diagram of the correct hose routing.
Reply
Old Aug 18, 2013 | 12:14 AM
  #7  
01ssreda4's Avatar
TECH Senior Member
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (96)
 
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Default

Factory pcv is simple. Fresh filtered air from TB to the front of the passenger valve cover, this would be an inlet to the crankcase. Then both valve covers vent at the rear, the lines combine in a Y to a single line, to a PCV valve, then to the intake (vacuum) neck, this is the waste exit. The LS6 valley mod deletes to two valve cover exits (they get plugged off) and replaces them with a single front valley cover exit. The earlier model valley required a PCV valve, the later did not because is had a built in restriction.
Reply
Old Aug 18, 2013 | 09:50 AM
  #8  
Trboboost91's Avatar
Teching In
 
Joined: Aug 2011
Posts: 11
Likes: 0
Default

That's what it looks like on a ls1 on a vette I looked at at the track.
But mine has 2 90 degree vents on the pass valve cover (1 for fresh air, and I assume 1 for the pcv line, but the drivers valve cover has a rubber grommet at the back big enough that it has a pcv valve in it, unlike the pcv valve in the line like you speak of.
According to vin the motor came from a 02 z28.
Not gonna lie, I'm pretty green to the Ls motor. But I'm willing and wanting to learn.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Aug 18, 2013 | 11:02 PM
  #9  
01ssreda4's Avatar
TECH Senior Member
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (96)
 
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Default

The driver hole is much bigger. My car had an elbow and reducer there and the PVC was located at the front of the engine. However, on older engines it was very common to have the PVC valve installed like you described.
Reply
Old Aug 23, 2013 | 10:44 AM
  #10  
S1dc_Drifter's Avatar
Thread Starter
Teching In
iTrader: (2)
 
Joined: Jul 2011
Posts: 27
Likes: 0
Default

Ok guys, So I have done some research and plan on doing the new ls6 valley cover with a dual catch can and leave the filler cap breather on. Hopefully this relieves the blow by.

One more question What happens do the driver side rear valve cover port. Does it just get plugged or is it routed to the passenger side?

Here is what I am going with

Reply
Old Aug 24, 2013 | 06:29 AM
  #11  
ssgunny's Avatar
TECH Enthusiast
iTrader: (6)
 
Joined: Jun 2007
Posts: 502
Likes: 1
From: RI
Default

I connected my rear drivers side valve cover port to the rear passenger side.
Reply
Old Aug 24, 2013 | 11:19 AM
  #12  
MIGHTYMOUSE's Avatar
TECH Senior Member
20 Year Member
Photogenic
Photoriffic
Liked
iTrader: (59)
 
Joined: Nov 2001
Posts: 10,018
Likes: 51
From: Virginia
Default

those catch cans won't help with blow-by. Your best bet is to put a wristband around the breather and replace it whenever it gets saturated
Reply
Old Aug 28, 2013 | 06:46 PM
  #13  
RockinWs6's Avatar
TECH Addict
 
Joined: Mar 2013
Posts: 2,628
Likes: 30
Default

Do a leak down test............check piston clearances. What did the builder say they were? something is way wrong.
Reply




All times are GMT -5. The time now is 06:01 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE