Results 1 to 16 of 16

Oil/Dirt in intake and runners

This is a discussion on Oil/Dirt in intake and runners within the General Help forums, part of the LSx Technical Help Section category; I noticed that when we took off the LS1 heads that the runners were very dirty with thick grime. You ...

  1. #1
    Junior Member corvet786c's Avatar
    Join Date
    Sep 2005
    Location
    Port St. Lucie Fl
    Age
    45
    Posts
    31

    Black
    2008 C6 Corvette LS3

    Oil/Dirt in intake and runners

    I noticed that when we took off the LS1 heads that the runners were very dirty with thick grime. You can see the diffrence where injectors squirt fuel. What causes this how can I prevent it?

  2. #2
    King 0f n00bz shady milkman's Avatar
    Join Date
    Jan 2006
    Location
    Shepherd, Michigan
    Age
    29
    Posts
    11,775

    blacker than wesleysnipes
    98' trans am

    Quote Originally Posted by corvet786c View Post
    I noticed that when we took off the LS1 heads that the runners were very dirty with thick grime. You can see the diffrence where injectors squirt fuel. What causes this how can I prevent it?
    getting oil pushed back into the intake...its a common thing with the lsx platform ...switch to a ls6 valley cover and get a catch can..then your intake manifold will get clean and so will your runners. ..als obe worth it to sea foam your car.

  3. #3
    Impounded
    Join Date
    Oct 2007
    Location
    Beaver Dam KY
    Posts
    7,746

    79 T/A -91 Firebird
    1998 Trans Am -Oynx Black

    Install an Oil Catch Can.

  4. #4
    Impounded
    Join Date
    Oct 2007
    Location
    Beaver Dam KY
    Posts
    7,746

    79 T/A -91 Firebird
    1998 Trans Am -Oynx Black

    Quote Originally Posted by shady milkman View Post
    getting oil pushed back into the intake...its a common thing with the lsx platform ...switch to a ls6 valley cover and get a catch can..then your intake manifold will get clean and so will your runners. ..als obe worth it to sea foam your car.
    Dammit.


  5. #5
    It happens in ALL engines. All you are seeing is the normal carbon build up from the combustion process that happens in the intake. I know you are going to say combustion happens in the cylinders how could it get back into the intake. If you could look inside the intake as the engine was running you would be shocked at what goes on in there. Flash over from the valves opening causes combustion gases and oil to get burnt in the intake.

    Try running Techron every 3k miles in the gas, it will help clean. You could run something like Lucas fuel system treatment in the gas all the time. This will keep it clean.

  6. #6
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    Quote Originally Posted by 99RTA View Post
    It happens in ALL engines. All you are seeing is the normal carbon build up from the combustion process that happens in the intake. I know you are going to say combustion happens in the cylinders how could it get back into the intake. If you could look inside the intake as the engine was running you would be shocked at what goes on in there. Flash over from the valves opening causes combustion gases and oil to get burnt in the intake.

    What you are speaking of is called "reversion". That is usually more prevelant with larger camshafts that have more overlap.

  7. #7
    No it happens in ALL internal combustion engines.......i don't care what the cam specs are.

  8. #8
    Member
    Join Date
    Nov 2008
    Location
    harrisburg pa.
    Age
    61
    Posts
    868

    black
    02 vette vert

    Quote Originally Posted by 99RTA View Post
    No it happens in ALL internal combustion engines.......i don't care what the cam specs are.
    i think he said "usually more prevelant", not :no it doesnt.

  9. #9
    King 0f n00bz shady milkman's Avatar
    Join Date
    Jan 2006
    Location
    Shepherd, Michigan
    Age
    29
    Posts
    11,775

    blacker than wesleysnipes
    98' trans am

    Quote Originally Posted by Firebirdjones View Post
    What you are speaking of is called "reversion". That is usually more prevelant with larger camshafts that have more overlap.
    Quote Originally Posted by 99RTA View Post
    No it happens in ALL internal combustion engines.......i don't care what the cam specs are.
    Quote Originally Posted by dklowrider View Post
    i think he said "usually more prevelant", not :no it doesnt.
    and we have a winner dklowrider come on down you are the next contestant on the price is right!

  10. #10
    Member
    Join Date
    Nov 2008
    Location
    harrisburg pa.
    Age
    61
    Posts
    868

    black
    02 vette vert

    Quote Originally Posted by shady milkman View Post
    and we have a winner dklowrider come on down you are the next contestant on the price is right!
    no, bright lights make me nervous.

  11. #11
    Its just something that all engines do.....some combustion takes place in the intake. Then as the engine gets older and the valves leak a little more it gets worse. Think about this if a intake valve leaks just 1% those combustion gases are going into the intake manifold where they are going to start burning on the way to to next intake valve that is open. Then also add thie fact that ALL engine also heat soak the intake causing carbon depoists in the intake and on the injectors.< that is a huge reason why injectors get blocked....they block from the heat soak carboning the exit holes in the injectors.

    Lesson for today is over...tune in next time for fun with Dick

  12. #12
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    Quote Originally Posted by dklowrider View Post
    i think he said "usually more prevelant", not :no it doesnt.


    Thank you sir,,,you are correct

  13. #13
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    To explain a little more, Reversion is exhaust gasses that are getting up through the intake valve during the combustion process,(aka: carbon),,this is completely different than oil in the intake that the original poster is talking about.

    The reversion process isn't so much of a problem in cars with stock camshafts. Most lobe seperation angles are spread out as far as 117 degrees to build low speed cylinder pressure by closing that intake valve sooner. Keep the exhaust gasses in the cylinder rather than escaping up through the intake track. If you have a valve seat leaking then you have other issues that need to be addressed.
    I've taken 150,000 mile stock motors apart and see more oil issues with worn valve guides coating the intake and exhaust valves than I've seen with reversion.

    Granted it does happen even with stock camshafts, it's not enough to even worry about. The biggest issue with these 4th gens is the PCV system that actually sucks the oil into and through the intake system. That's what needs to be addressed and can be stopped.
    There is nothing you can do about reversion. And more people are sticking larger camshafts in these cars every day, which makes reversion more prevelant. Those are the ones to keep an eye on. Although it's just a necessary evil we live with. You want to make more high rpm power with a high overlap camshaft, you get reversion.

  14. #14
    Junior Member corvet786c's Avatar
    Join Date
    Sep 2005
    Location
    Port St. Lucie Fl
    Age
    45
    Posts
    31

    Black
    2008 C6 Corvette LS3

    I just got new afr heads put on so I know it is no valve leak. I just want to clean intake and dont want that garbage on the new heads. U know what I mean. I just ordered a catch can hope this helps with oil in intake.

  15. #15
    Member
    Join Date
    Nov 2008
    Location
    harrisburg pa.
    Age
    61
    Posts
    868

    black
    02 vette vert

    Quote Originally Posted by corvet786c View Post
    I just got new afr heads put on so I know it is no valve leak. I just want to clean intake and dont want that garbage on the new heads. U know what I mean. I just ordered a catch can hope this helps with oil in intake.
    im new to these cars and learning things almost daily, that is next on my list. at113k its a little late to worry about the oil deposits, but at least i wont be mixing the oil into the intake stream, should run better but i dont know if its a seat of the pants improvement though. the can from the ws6 store is a pretty good price, i dont know yet if it works or is just a can without a screen or something to promote the oil and condensation dropping out of the air.

  16. #16
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    Quote Originally Posted by corvet786c View Post
    I just got new afr heads put on so I know it is no valve leak. I just want to clean intake and dont want that garbage on the new heads. U know what I mean. I just ordered a catch can hope this helps with oil in intake.

    Yes,,,reversion that 99RTA mentioned would allow combustion or carbon to come up through the intake valve. I think he got that confused with the oiling problem through the PCV that it appears you are experiencing.
    To be sure you can pull the throttle body and stick your hand in the intake just behind the throttle body and feel around,,,if it's oily residue then it's the PCV. You can also pull the PCV apart and check for oil inside the hose, PCV etc... In some cases such as mine, it would back flow (somehow) and puddle up in front of the throttle body in the bottom of the smooth bellow.

    The catch can will stop it from entering the intake system.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Do we have variable runners on our intake manifolds?
    By Naaman in forum External Engine
    Replies: 5
    Last Post: 02-07-2013, 05:06 PM
  2. LS6 intake manifold and 227 Intake runners
    By IT_SS in forum Internal Engine
    Replies: 4
    Last Post: 07-07-2009, 03:11 PM
  3. Question: 227 CC intake runners
    By IT_SS in forum Internal Engine
    Replies: 9
    Last Post: 05-29-2009, 12:07 PM
  4. Question for the runners out there
    By grandkodiak in forum Almost Anything Goes
    Replies: 29
    Last Post: 05-15-2007, 07:16 PM
  5. 15” x 4” front runners
    By Trolleyman in forum Wheels and Tires
    Replies: 2
    Last Post: 08-24-2006, 03:39 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •