pressure build up
Thread Starter
Teching In
Joined: May 2015
Posts: 11
Likes: 0
pressure build up Today i changed valve cover gaskets and oil and filter.When i started the motor and ran it for a while turned it off i could hear hissing noise coming from the pvc hose.My motor has the pvc hose going from the passenger valve cover to the manifold behind the throttle body.Anyway upon further investigation i noticed that after switching off the motor pull out the dipstick or take the oil filler cap off and there seems to be a build up of pressure.The motor has just had the cam done and a tune done a couple of days ago with no problems.Only seems to have started after oil and filter change.Pvc seems to be working as well.
Nope PCV routing is rear of driver's side connects to rear of passenger side. Front of passenger side valve cover port connects to PCV valve, which connects to the intake at the throttle.
Define "PCV seems to be working". It sounds like it's not working.
Define "PCV seems to be working". It sounds like it's not working.
Trending Topics
Thread Starter
Teching In
Joined: May 2015
Posts: 11
Likes: 0
I just went and run the motor and it is sucking air not blowing so its a vacuum issue.I now have both valve covers connect to the manifold and when i shut down the motor it sucks air for about 5 seconds.I have after market valve covers which only have one port each.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'
Brett Foote
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
OK. My valve covers have two ports each, so you won't be able to route it my way. I'm thinking something got in while your valve covers were off and are blocking that port. Maybe old gasket material or something.
With one port on each valve cover, one needs to "vent" to let air in and the other draws to the intake. Try putting it back the way you had it at first and unblocking the drivers side tube - let it just vent to open air
With one port on each valve cover, one needs to "vent" to let air in and the other draws to the intake. Try putting it back the way you had it at first and unblocking the drivers side tube - let it just vent to open air
I have recently been doing a ton of research on the PCV systems on the LS engines and adding oil/air separators. The stock LS1 setup is horrible on these engines as most people know, allowing oil soaked mist to go into the intake and reduce the octane rating of the fuel.
Basically your engine creates pressure due to blow by through the piston rings, that pressure enters the crank case and builds up. It has to be released or it can blow out your seals. But venting to atmosphere causes bad smells and allows the engine to build up a milky sludge, this happened to me! The port on the passenger valve cover towards the front of the engine should connect to the intake manifold, that creates vacuum to pull out the pressure build up. You use the front port on the valve cover because when you accelerate the oil with fill up to the rear of the valve cover and will cause excessive oil into your intake at WOT if vacuum is pulled at that rear port into the intake. You should also run a oil/air separator between that connection and the intake to stop any oil mist from going into your throttle body. So that takes care of the vacuum, but you need to allow the engine to pull air from somewhere because the vacuum at idle will be more than the pressure created by the blow by. So the rear ports on the valve covers should be connected and ran to the air intake between the throttle body and air filter.
Only difference I would do is use the front and not the rear to connect to the vacuum port to the intake and add a oil/air separator between them.
Basically your engine creates pressure due to blow by through the piston rings, that pressure enters the crank case and builds up. It has to be released or it can blow out your seals. But venting to atmosphere causes bad smells and allows the engine to build up a milky sludge, this happened to me! The port on the passenger valve cover towards the front of the engine should connect to the intake manifold, that creates vacuum to pull out the pressure build up. You use the front port on the valve cover because when you accelerate the oil with fill up to the rear of the valve cover and will cause excessive oil into your intake at WOT if vacuum is pulled at that rear port into the intake. You should also run a oil/air separator between that connection and the intake to stop any oil mist from going into your throttle body. So that takes care of the vacuum, but you need to allow the engine to pull air from somewhere because the vacuum at idle will be more than the pressure created by the blow by. So the rear ports on the valve covers should be connected and ran to the air intake between the throttle body and air filter.
Only difference I would do is use the front and not the rear to connect to the vacuum port to the intake and add a oil/air separator between them.
TECH Addict
Joined: Aug 2005
Posts: 2,305
Likes: 126
From: Monroe,NY
On my 5.3 the passenger side goes to the intake manifold and the passenger side goes to the cai intake for fresh air. The driver side needs fresh air coming in you can't block port off on valve covers. You can just put a breather on it.
OP, on that picture that "rabid" posted...
Air flows from the throttle (so, it's filtered air, not unfiltered) to the valve cover. Then, vacuum draws from the rear ports through the PCV to the intake manifold.
In your case, you can't connect the rear ports, so you can't run that set up. You would just have to run one port to the PCV and then the intake, and leave the other port open. put a breather on the open port for filtered air going through the block.
If you're game for it, take the intake manifold off, get the LS6 valley cover with the PCV integrated into the cover, then you just loop a short vacuum line from the valley cover to the intake manifold. Solves the whole problem.
Air flows from the throttle (so, it's filtered air, not unfiltered) to the valve cover. Then, vacuum draws from the rear ports through the PCV to the intake manifold.
In your case, you can't connect the rear ports, so you can't run that set up. You would just have to run one port to the PCV and then the intake, and leave the other port open. put a breather on the open port for filtered air going through the block.
If you're game for it, take the intake manifold off, get the LS6 valley cover with the PCV integrated into the cover, then you just loop a short vacuum line from the valley cover to the intake manifold. Solves the whole problem.
Exactly what I did except I put a air/oil separator between the LS6 valley cover and the intake