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Thread: Heard of warped intake?????

  1. #1
    Join Date
    Jul 2002
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    Heard of warped intake?????

    I have been trying to chase down oil in my intake manifold but not anywhere else in the tubes, intercooler, plenum, etc. We have reinstalled the intake 3x to no avail. A leak down shows 16% on 5 cylinders and 19% on one cylinder as the high. Bottom end recently rebuilt. Intake manifold was ported during rebuild.

    As far as I know, there is no way that oil can get into the intake other than a bad intake seal or blow by. But nothing indicates blow by (good leak down results, and no oil in the intercooler or tubes other than usual). Ever heard of a warped intake manifold resulting in a bad seal? Any help is immensely appreciated. larry

  2. #2
    how much oil? It can get in thru blow-by because the PCV valve connects to the back of the blower inlet.

    Brian

  3. #3
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    Some oil in the intake from the PCV system is a common thing on these cars. Especially if the PCV valve has been replaced with an aftermarket one - Ford has a special valve for the SC that supposedly works best, it's only a couple bucks from Ford.

  4. #4
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    As stated, no oil in tubes, plenum, or intercooler. And, leak down appears very good. No signs of blowby. Must be something with intake manifold unless anyone can steer me otherwise. Thanks for responses! L

  5. #5
    Have you had your heads resurfaced?
    Have you decked the block?

  6. #6
    Join Date
    Sep 2002
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    Oil gets in to the intake it's vary normail for the SC you will find more oil if you have a 5%or 10% over drive thats what I have found.

    No big deal just clean it ever so often.

  7. #7
    Jason its not normal to get oil ONLY in the intake manifold and not anywhere else in the intake tract.
    Reread his posts.

  8. #8
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    yea, heads were milled slightly (know where you're headed). Block did not need to be decked, appears sufficient gap between intake and block at ends. Oil is not slight in intake. In fact, enough to foul plugs thus producing knock. To confirm, it appears that the rest of the intake is clean and no sign of blowby. This is really wierd. Pulled intake to have machine shop verify that mating surface are true. Anything else? Install on intake is not the issue but must be something related to manifold. L

  9. #9
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    Larry,

    Is it possible that you have the PCV valve hose connected to the intake manifold adaptor instead of the inlet plenum ? This would draw oil mist directly into the intake manifold while the engine is pulling a vacuum and would not contaminate the rest of the intake with oil. Under boost it would pump air into the crankcase and if revved hard might even cause a little oil to come out of the dipstick tube.

    David
    1991 SC AOD 4.2..2.3 Whipple..........10.910 @ 125.61
    2016 SRT Challenger Hellcat...............707HP/650TQ

    My Garage

  10. #10
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    David, we thought that may be the case so we quadruple checked all of our connections, that's one that I would have wanted to be wrong on, if you know what i mean. Appreciate the brainstorm cause we are stumped unless something obvious is wrong with the intake. Larry

  11. #11
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    u said in previuos post ..that the intake was pertty clean its self but oil is fouling your plugs correct?..... how about your valve seal! if leaking they could foul your plugs up also and or an incorrectly seated valve could of gave u the leakege on your highest cylinder. etc could be a combination of the both or either one

  12. #12
    Originally posted by LarryH
    yea, heads were milled slightly (know where you're headed). Block did not need to be decked, appears sufficient gap between intake and block at ends. Oil is not slight in intake. In fact, enough to foul plugs thus producing knock. To confirm, it appears that the rest of the intake is clean and no sign of blowby. This is really wierd. Pulled intake to have machine shop verify that mating surface are true. Anything else? Install on intake is not the issue but must be something related to manifold. L
    Well I was'nt saying that maybe the intake ends were touching the block thus holding the intake away from the heads. What you get into is when you resurface the heads or block that inturn changes the degree of angle in relation to the unmachined intake manifold surfaces. There have been times I've had to have an intake machined after having heads resurfaced. I'd take a good hard look at that because that may be your problem. On the other hand the intake itself may be warped because of unevenly torqued bolts. The piece is Aluminum and highly suseptable to that kind of thing.

  13. #13
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    sorry, i assumed what you were eluding to (gotta stop that). Manifold is being checked now. Appreciate the idea regarding the altered angles. That's possible but the heads were only slightly milled and the block was not. Thanks L

  14. #14
    That normaly should'nt be a problem, but I did'nt know if you knew for sure if they had been resurfaced prior to you owning the car or not. Just something to look at.

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