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2012 Knock/Chirp on cold start

Discussion in 'Ford Raptor Engine Discussion and Performance Mods' started by BrandonSVT, Mar 29, 2020.

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  1. BrandonSVT

    BrandonSVT Member

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    After getting my Kooks installed I started the truck up one morning to go to work and noticed an odd sound from the driver's fender well. Sounded like some sort of knock but then it sounds like a bad pulley bearing and then it goes away. It only comes on a cold start and sometimes it last 5 seconds and sometimes it last 30 seconds. I have searched every 6.2 noise video on the internet and nothing sounds exactly like this. I have owned the truck since new and it currently has 84k miles.

    I was worried it was a rod knock so I dropped the front differential to service it and while I did I dropped the oil pan. No issues in the bottom end. No play/movement in anything and pretty dang clean from running synthetic Mobil 1 for 84k miles. I have since removed the driver side valve cover since I'm going to replace them anyway and pulled the intake side rocker shaft to inspect the rockers. I haven't found any smoking gun but I was wondering if anyone has any experience with the rockers on the 6.2? Should the lash adjusters that are built in to the rocker be stiff or have some give to them? They have an articulating flat head that sits right on the valve stem and two of them you can push in some and the other two are solid. I am going to pull the exhaust side rocker shaft too and see if anything looks abnormal.

    Here's a video

     
  2. BrandonSVT

    BrandonSVT Member

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    A few pics of my inspections. Again, amazed at how clean everything is in here.

    20200326_190324.jpg

    20200329_161245.jpg

    20200329_161238.jpg
     
  3. B E N

    B E N Full Access Member

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    So this occurred only after you put the headers in? Check for marks where the headers are hitting, make sure the y-pipes are tight when cold.
     
  4. FordTechOne

    FordTechOne Full Access Member

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    I'm impressed...you pulled the pan and checked the lower end before even posting!

    Engine definitely looks very clean. Have you by chance inspected the serpentine (Front End Accessory Drive/FEAD belt in Ford term) for a knocking tensioner while the concern is occurring? it's possible that during a cold start at high idle, the tensioner is failing and generating the noise in your video.

    I have seen 6.2's break valve springs on occasion, but it generally results in a misfire and the issue doesn't go away once the engine warms up.

    Here is the diagnostic information from the Workshop Manual:

    • Engine noise, upper end — ticking, knocking or rattle noise that occurs during idle or high idle during the first cold start of the day and may disappear as the engine warms
    • Valve train noise (bled down lifter/lash adjuster/valve tappet)
    • CARRY OUT the Valve Train Analysis Component Test in this section. INSTALL new parts as necessary. Refer to the appropriate section in Group 303 for the procedure.

    Valve Train Analysis — 6.2L (2V)

    The following component tests are used to diagnose valve train concerns.

    Valve Train Analysis — Engine Off — Valve Cover Removed

    Check for damaged or severely worn parts and correct assembly. Make sure correct parts are used with the static engine analysis as follows.

    Valve Train Analysis — Engine Off, Rocker Arm and Overhead Camshaft
    • Check for loose mounting bolts on rocker arm shafts and camshaft carriers.
    • Check for plugged oil feed in the rocker arm shafts and cylinder heads.
    Valve Train Analysis — Engine Off, Camshaft
    • Check for broken or damaged parts.
    Valve Train Analysis — Valve Springs
    • Check for broken or damaged parts.
    Valve Train Analysis — Engine Off, Valve Spring Retainer and Valve Spring Retainer Keys
    • Check for correct seating of the valve spring retainer key on the valve stem and in valve spring retainer.
    • Check for correct seating on the valve stem.
    Valve Train Analysis — Engine Off, Valves and Cylinder Head
    • Check for plugged oil drain back holes.
    • Check for worn or damaged valve tips.
    • Check for missing or damaged guide-mounted valve stem seal.
    • Check installed valve spring height.
    • Check for missing or worn valve spring seats.
    • Check for plugged oil metering orifice in cylinder head oil reservoir (if equipped).
    Static checks (engine off) are to be made on the engine prior to the dynamic procedure.

    Valve Train Analysis — Engine Running, Valves and Cylinder Head
    • Check for plugged oil drain back holes.
    • Check for missing or damaged valve stem seals or guide mounted valve stem seals.
    • Check for a plugged oil metering orifice in the cylinder head oil reservoir.
    If insufficient oiling is suspected, check oil passages for blockage, then accelerate the engine to 1,200 rpm with the transmission in NEUTRAL and the engine at normal operating temperature. Oil should spurt from the rocker arm oil holes such that valve tips and camshaft roller followers are well oiled. With the valve covers off, some oil splash may overshoot camshaft roller followers.

    Valve Train Analysis — Camshaft Lobe Lift

    Check the lift of each camshaft lobe in consecutive order and make a note of the readings.
    1. Remove the spark plugs. Refer to Section 303-07D.
    1. Install the Dial Indicator Gauge with Holding Fixture so the rounded tip of indicator is on top of the camshaft lobe.
    1. Rotate the crankshaft using a breaker bar and socket attached to the crankshaft pulley retainer bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached.
    [​IMG]
    1. Zero the Dial Indicator Gauge. Continue to rotate the crankshaft until the (1) high-lift point of the camshaft lobe is in the fully-raised position (highest indicator reading).
    1. To check the accuracy of the original indicator reading, continue to rotate crankshaft until the (2) base circle is reached. The indicator reading should be zero. If zero reading is not obtained, repeat the measurement.
    1. If the lift on any lobe is below specified service limits, install a new camshaft and camshaft roller followers.
    1. Install the spark plugs. Refer to Section 303-07D.
     
  5. Canuck714

    Canuck714 Full Access Member

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    So what did you discover??
     
  6. BrandonSVT

    BrandonSVT Member

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    So I pulled both intake and exhaust rocker shafts and inspected the hydraulic lash adjusters. The video above is what I found. The intake and exhaust side had 2 of the four adjusters that I could compress by hand and 2 I couldn't. I bought a new OEM exhaust shaft rocker at a deal so I would know what a new part acts like and they are all solid and not compressible. Thinking this may be the issue I went ahead and replaced the exhaust side rocker shaft but this didn't fix the issue. I haven't got around to the tensioner check yet. The video below shows a new shaft rocker compared to the old one. The new ones have a metal case around the tip versus a phenolic looking material.

     
  7. BrandonSVT

    BrandonSVT Member

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    Also worth noting that if you wanted to know if your engine was a raptor 6.2 or other 6.2, all the engine components have markings from the factory where they where torqued and then a match mark put on them. Pretty cool.
     
  8. pat247

    pat247 Full Access Member

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    My Raptor has made a similar noise on cold starts since day one and like you said goes away after a few seconds. My truck has 150k miles and nothing has broken yet that I know of.
     
  9. BrandonSVT

    BrandonSVT Member

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    Sorry I don't have any updates on this guys. Seems like switching from Mobil 1 5-20w to Amsoil 5-30w has made this issue less frequent but every now and then I still hear it. I think its something that's been there but was amplified by the longtube headers.
     

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