4.6 DOHC in F100 - Rattling sound in engine / transmission - Help please!

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  1. #1

    Default 4.6 DOHC in F100 - Rattling sound in engine / transmission - Help please!

    Maybe some of you guys have ready seen my build thread on here, have a question regarding a noise when running.

    Last November, was able to start the engine for the first time after (partially) rebuilding it.

    Done on the engine:
    - Heads removed
    - Valves surface lapped
    - New valve stem seals
    - New lifters
    - New chains and tensioners
    - All new gaskets
    - 5W30 synthetic oil
    - Engine put together using assembly lube
    - Oil pump packed for proper priming
    - Engine had oil pressure almost immediately after starting
    - New plugs

    Used Motorcraft or ACDelco on everything.

    Haven't touch the short block itself. I drive the car up to Norway after i bought it (1200 Miles), no noises or smoke, engine was running fine. Only small rattling sound coming from the chain tensioners at start-up, that's now fixed btw.

    Transmission:
    - New flexplate
    - New TC
    - New TC nuts
    - New filter & oil (Mercon V)

    All electrical sensors new, no codes found when doing the KOEO tests. I have only run the engine briefly as the cooling system was not finished yet. Also only the cats installed, no exhaust system yet.... Haven't done the KOER tests, didn't want to run the engine too long.

    I have just uploaded the video to YouTube:

    https://youtu.be/1gfSVhduZKg

    In the video (45 seconds in), i rev up the engine a bit and when the revs drop there is a rattling / knocking sound? It disappears completely when at idle speed. Around 58 second i rev it up again slightly, same sound that disappears at idle.

    Am currently offshore and am reading every thread on here and also http://forums.tccoa.com to see what it could possibly be. Hope its something simple as a collapsed lifter... not a rod bearing or worse.... Was able to locate the sound, around cylinder 8 more near the bellhousing area. Have shortly listened to the head using a screwdriver near my ear, couldn't pinpoint it.

    As soon as i get back in March i am going to do some more investigation but was hoping that one of you guys might be able to tell what it could be from experience.

    Thanks in advance, Willem Holman

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  3. #2
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    Yes watched your vid and sounds like a valve train noise and then the misfire in the beginning confirms, to me at least, that something went wrong in cam and valve area, remove your valve covers and examine

  4. #3

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    Hi Tellerx1,

    Thanks for your reply on this. My initial thought was valve train also, especially because i took it all apart and installed new lifters. Did use assembly lube on the cam journals when installing them, so hopefully nothing wrong with the cams. Did also put the lifters in an oil bath for a day or so, as recommended in the Shop Manual.

    Have found this 2V 3V 4V Valve Spring Compressor tool online, i believe its the only tool that does all 4.6 engines:

    http://www.freedomracing.com/4v-v8-2...or-st-126.html

    Also need some stuff from Summit Racing so will order 2 new lifters, just in case. All cam lobes and followers looked in great shape so they went back in the heads again.

    Did you post a reply on Youtube also?! Didn't write any details on Youtube, maybe i will do that later for others that are not on this forum.

    Thanks again, Willem

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  6. #4
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    It sounds like a lifter.
    Yes the Freedonracing spring kompressor toll is working for 4V.
    I have one but had to modify it slightly. For some valves it hit the heads and wasn't able to compress the spring.
    Some grinding on the tool fixed it.

  7. #5

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    Hi Tbird,

    Thanks for your reply. Sure hope its a lifter.... Am ordering 2 lifters so hopefully it will be fixed after. I'll try the tool and see if i need to modify it, thanks for the heads-up!

  8. #6

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    @TellerX1 (or anybody else reading this!)

    You mentioned a misfire in the beginning, not sure when that happened... Could you tell me around when in the video?!

    Thanks Willem

  9. #7
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    yes i believe i heard the misfire happen twice or three times, at the beginning, before you rev the motor

  10. #8
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    Yes i even went back just now and once again listened to the video 2 more times and heard that misfire. Right at the initial start up you can hear an out of rhythm bump from what sounds like might be coming from the exhaust. Misfires are quite common with valve train trouble
    Last edited by tellerx1; 02-08-2018 at 07:51 PM.

  11. #9
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    Hey thats a small fix, in comparison to what you've accomplished. Getting that motor running so well is a feat some of us only dream of.

  12. #10

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    @Tellerx1,

    Thanks for the compliment man! I must admit that i am a bit proud of what i have done so far. Have worked on cars before but not a project like this.... That's why i started my build-thread, for myself to look back and also for others to encourage them.

    Thanks for the info on the backfires, can hear it now also when i play the video, does sound like its coming from the exhaust..... I have ordered two aluminum 10 mtrs ducts, will connect them to the exhaust next time i am home. Then at least i can focus on the engine sounds only and not the exhaust... I guess not breathing in exhaust fumes is a bonus also hehehe

    Thanks Willem

  13. #11

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    Hi to all that have been posting in this thread. I have been working on identifying the noise and have not gotten to the bottom of it...

    What i have done:

    - Installed Transmission without TC, just to make absolutely sure the noise came from the engine and not the tranny. Ran engine for 30 seconds, noise still there so tranny ok. Installed Transmission with TC, new Hayden tranny cooler and filled up with oil.
    - Drained the engine oil (5W30 from a nameless brand, only ran couple of minutes after rebuild...), filled up with Castrol 5W30. The "old" oil was completely clean when drained from the engine.
    - Removed all 32 hydraulic lifters and inspected for damage and tried to compress them. All lifters felt the same, solid and not possible to compress. - Inspected both heads / valvetrain / cam lobes etc. Could not see any visible damage or marks or other.
    - Finished cooling system, filled up with coolant.
    - Installed IMRC vacuum control valves and vacuum system.

    Connected exhausts to Aluminum flex-pipe and routed outside my tent/garage to be able to run the engine for longer periods. Bought an engine stethoscoop so i could listen better as to where the noise comes from.

    - Ran the engine for longer periods and made sure it was at normal operating temperature.

    After a while i sort of located where the noise is the "loudest". The noise is the loudest at Cylinder 4 and i can hear it most clearly when i have the end of the stethoscoop on the bracket of the IMRC vacuum control valve....... As if that is not confusing enough: The noise is louder when the IMRC's are open (vacuum disconnected from IMRC valve). The noise is present at all RPM's when you listen with the stethoscoop.
    When listening "normal", its only when letting of the throttle.

    So what i am thinking is that there is an issue with the Cylinder 4 inlet valve / lifter that is getting used when the IMRC's are open (above 3000 rpm). Unfortunately i didn't have more to to investigate before having to return to work (now offshore) so i will have to do more checks when i get back. I have bought 2 spare lifters so going to change them out and do some checks.

    Another question i have:

    - Should the engine keep running when at idle speed and the IAC valve electrically disconnected? Or should the engine stall due to lack of air going in the engine? I am asking because another issue i have with the engine is that it doesn't respond immediately when i come off the throttle. It takes a couple of seconds for the RPM's to return to idle speed. It just doesn't feel right......

    So as a test, i disconnected the Idle Air Control valve and when it's disconnected, the engine responds better to the throttle...... But the idle speed is a bit lower.... If the IAC valve is completely closed when electrically disconnected, it could mean i have a big vacuum leak somewhere and thats causing the engine to "run on a bit" after i come off the throttle. If that makes sense?!

    In the back of my mind i am thinking that the above mentioned 2 issues are sort of related to a problem in the intake manifold or IMRC's... So i have ordered new Mahle gaskets (MS16275 & MS16276) for the intake assembly. Think i will take if off to inspect, just in case.

    Thanks Willem

    Read more at: https://www.modularfords.com/threads/...on-Help-please!

  14. #12

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    Quote Originally Posted by Iamsterdam View Post
    Hi to all that have been posting in this thread. I have been working on identifying the noise and have not gotten to the bottom of it...

    What i have done:

    - Installed Transmission without TC, just to make absolutely sure the noise came from the engine and not the tranny. Ran engine for 30 seconds, noise still there so tranny ok. Installed Transmission with TC, new Hayden tranny cooler and filled up with oil.
    - Drained the engine oil (5W30 from a nameless brand, only ran couple of minutes after rebuild...), filled up with Castrol 5W30. The "old" oil was completely clean when drained from the engine.
    - Removed all 32 hydraulic lifters and inspected for damage and tried to compress them. All lifters felt the same, solid and not possible to compress. - Inspected both heads / valvetrain / cam lobes etc. Could not see any visible damage or marks or other.
    - Finished cooling system, filled up with coolant.
    - Installed IMRC vacuum control valves and vacuum system.

    Connected exhausts to Aluminum flex-pipe and routed outside my tent/garage to be able to run the engine for longer periods. Bought an engine stethoscoop so i could listen better as to where the noise comes from.

    - Ran the engine for longer periods and made sure it was at normal operating temperature.

    After a while i sort of located where the noise is the "loudest". The noise is the loudest at Cylinder 4 and i can hear it most clearly when i have the end of the stethoscoop on the bracket of the IMRC vacuum control valve....... As if that is not confusing enough: The noise is louder when the IMRC's are open (vacuum disconnected from IMRC valve). The noise is present at all RPM's when you listen with the stethoscoop.
    When listening "normal", its only when letting of the throttle.

    So what i am thinking is that there is an issue with the Cylinder 4 inlet valve / lifter that is getting used when the IMRC's are open (above 3000 rpm). Unfortunately i didn't have more to to investigate before having to return to work (now offshore) so i will have to do more checks when i get back. I have bought 2 spare lifters so going to change them out and do some checks.

    Another question i have:

    - Should the engine keep running when at idle speed and the IAC valve electrically disconnected? Or should the engine stall due to lack of air going in the engine? I am asking because another issue i have with the engine is that it doesn't respond immediately when i come off the throttle. It takes a couple of seconds for the RPM's to return to idle speed. It just doesn't feel right......

    So as a test, i disconnected the Idle Air Control valve and when it's disconnected, the engine responds better to the throttle...... But the idle speed is a bit lower.... If the IAC valve is completely closed when electrically disconnected, it could mean i have a big vacuum leak somewhere and thats causing the engine to "run on a bit" after i come off the throttle. If that makes sense?!

    In the back of my mind i am thinking that the above mentioned 2 issues are sort of related to a problem in the intake manifold or IMRC's... So i have ordered new Mahle gaskets (MS16275 & MS16276) for the intake assembly. Think i will take if off to inspect, just in case.

    Thanks Willem

    Read more at: https://www.modularfords.com/threads/...on-Help-please!
    Man, you are putting a ton of money and labor into it. Soon you are going to wear out threads in block. I would put it together, spray gaskets & vacuum hoses to check for air leaks, and run it. Where you sailing. MV? I guess no SS unless on lakes.

  15. #13

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    Hi Power,

    Thanks for your reply. Yes i have been a bit busy but hope to drive it in the summer.....

    After doing some more reading on here and other forums (http://forums.tccoa.com) i understand that the IAC vlave should be closed when electrically disconnected, so that leaves me with 2 options:

    - IAC valve is stuck open, although its a new one (Standard)
    - Vacuum leak somewhere...

    Will mount the old IAC valve to see if that cures it, otherwise i will spray everything with some Start Help gas.

    I work on an construction vessel / pipelayer offshore Angola, on a 6 weeks on - 6 weeks off rotation, so plenty of time to work on the car once i get back!

    Thanks Willem

  16. #14
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    IAC is a valve controlled with PWM (Pulse Witdh Modulation).
    It works with 12V and 0V and needs to modulate with these two voltage.
    To have the best working enviroment it shall modulate between 30 - 70 % opening.
    On Ford system the following will be a really good starting point.
    If the idle speed with IAC (the engine speed is controlled from PCM) is 750 rpm.
    Then when you disconnect the IAC (fully closed) the idle speed shall be around 150 rpm less. In this case 600 rpm.
    To set the idle speed without IAC is done with adjusting the throttle stop screw.
    With this setup the IAC will be in a good working range.

    Lifters.
    They have be able to bleed within a certain time frame.
    This can easy be tested before installation.
    Compress each lifter in a wise with clean and semi soft jaws and the bleed down time shall be (if I remember correctly) between 5 - 15 seconds.
    Most common is that they can't be compressed when faulty.
    Just replace the bad ones with new.

  17. #15

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    Tbird, thanks for your reply.

    Going by your reply on the IAC, the engine should NOT stall when the IAC is disconnected (providing there is no vacuum leak somewhere)? It idles around 750 and does go down to around 600 when i disconnect the IAC, so that could mean there is no vacuum leak. Going to do some more testing when i get back.

    Have seen this on Ebay after hearing people talking abot this forum: https://www.ebay.com/itm/122253622374

    It restricts the airflow through the IAC and drops the rpm's quicker when letting of the throttle.


    Regarding the lifters: I removed everyone of them and sort of compressed them using big pliers with the jwas procted with some tape. They all felt the same, pretty hard..... So i guess i will take the ones near the noise out again and test them in the vice.

    Thanks again for your reply, Willem

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