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Yet another engine noise

Discussion in 'Mondial' started by MvT, Aug 21, 2014.

  1. MvT

    MvT F1 Rookie
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    #1 MvT, Aug 21, 2014
    Last edited: Aug 21, 2014
    guys, another engine noise story! Got something disturbing the last time when I cranked her up in the morning. I have this weird sound I cannot realy place with this type of engine. To me it would sound like hydrolic valve lifters, but of course this engine does not have any :) It's like the sound of a marble going round in the heads. Oil pressure good. After a min or two it's gone. Had this last year as well when it was starting to get colder.. However duration was much less and most of the time it was not there. Sound doesn't come from the airco.

    So what I did recently:
    - Camshaft seal was leaking and replace it.
    - Took the followers out and honed them. All where good and no movement
    - Was also time for an oil change. Used 20w50
    - New MANN filter
    - Did two valve clearance adjustments. 1 exhaust was at 0.25 and made it 0.30 and 1 intake was at 0.15 and made it 0.20
    It's a bit strange as the last time they were correct and I didn't change any valve clearance.
    - Put everything back together, no missing parts ;) and torqued everything down with the right levels.

    Drove 700miles and then yesterday morning when the outside temp dropped to 10ºC/50ºF got this strange marble noise again, but a bit louder then last year. then after a minute it was gone. Drove 100miles. No issues. However I could hear a valve having to much glearance. (hmm strange.. was the valve clearance good afterall? Always check clearance two times) Oil pressure still good.

    Any comment appreciated. Will take things apart tomorrow again.

    Let's here the noise.

    [ame=http://www.youtube.com/watch?v=MIU9HBxXV_U]Engine Noise - Part 1 - YouTube[/ame]
     
  2. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
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    Hey MvT we can hear 2 sounds, first of all there is the higher pitch noise that sounds like a cracked manifold type 'BLOW'
    BUT there also is a kind of rattle at the end of the clip as well? or is that the recording?
    First check compressions....
    and is that a manifold blow sound, it's hard to tell from the clip?

    A manifold crack and blow would go as it heats up..
     
  3. raf456

    raf456 Karting

    Jan 27, 2013
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    Robert Freiburghouse
    My marble was also elusive and was eventually found to be the innards of one of the cats had come loose (or not loose depending on ??). New cats or test pipes are the solution for my marble.
    Bob
     
  4. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
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    How are you cranking without starting the engine.
    I ask this because I can hear 2 instances of the sound I think at 3:29 and 3:31
    It sounds to me like a combustion leak sound, the big question is, is it outside the engine, ie cracked manifold or inside, leaking valve...
    I'm thinking out load here.....
    It sounds like a very high up leaking exhaust manifold sound I think..
     
  5. billh1963

    billh1963 Formula Junior
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    That sounds to me like something loose on the outside. Does not sound internal to me because it does not match engine rpm

    My thoughts are (in no particular order)
    1. loose heat shield
    2. a/c compressor
    3. bad bearing on a/c or water pump
    and, my number one thought...are you sure it's not static discharge on the belts? When it's cold they make weird noises as static discharge occurs until they warm up. Start the car in the dark and look at the belts while the engine is running and see if you see any sparks

    Get a piece of hose and put one end to your ear and move the other end around to carious components. You will narrow it down
     
  6. MvT

    MvT F1 Rookie
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    #6 MvT, Aug 21, 2014
    Last edited: Aug 21, 2014
    We have no cats in Europe up to 1989 :) Thought of someting in the exhaust as well, but it is really the upper side of the engine from where the sound is coming from.

    I film with a GoPro :cool:

    Took out the fuelpump relays for the cranking. There are indeed two instances of sounds during cranking. I guess that is the noise. We also have to different noises. One I didn't her and see before. Let's call the first the marble sound and in the end the engine had a bit bonking backfire behavior (didn't do that before). Now when I turned it off I heard a hissing sound from the intake manifold (didn't heard it either before). The sound when you squeeze out a sponge or when you step in very wet packed tree leaves.

    I haven't checked the manifold. I will check however I have a feeling it doesn't sound like it plus when I hear from under the car it is very much less.

    I have a feeling it is a valve or valve seat. I hope so not! :eek: However cranking the engine does not give any weird noises..
     
  7. MvT

    MvT F1 Rookie
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    Thanks Bill for the checks
    1. I will check. however usually it tight them up very good as I hate loose shield.
    2. I checked. (with a hoose) seems not to be the airco.
    3. Pump is new 2000 miles old.

    I check indeed with a hoose and the noice is strongest at the front bank!
    I will lose up all belts airco, waterpump, alternator just to be sure.
     
  8. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
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    Yes but a leaking valve would start to be noticed under combustion first. I thought inlet at first but that would be unusual as they hardly ever burn, if it were a valve it would be exhaust and it could start with a sound like this BUT a compression check is going to show that up I have no doubt.
     
  9. MvT

    MvT F1 Rookie
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    btw Bell has your sound disappeared with the new followers?
     
  10. billh1963

    billh1963 Formula Junior
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    Don't forget the static discharge theory. If the noise goes away after the engine warms up a little that's it
     
  11. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
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    No, my sound stayed the same after everything I did.
    It only went once I changed the oil and that points to valve guide exhaust side.
    The sound has gone but I will investigate the valve Christnas time.
    For now I'm just having fun in the car which is going great guns.
     
  12. bartzagato

    bartzagato Formula Junior

    Aug 7, 2010
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    Hi Tijn

    Sorry to hear your troubles.

    Oil pressure comes up after the engine started, let's say roughly a big sec after the moment the engine runs. The meter takes perhaps a bit more time to get on the job. This is all normal and you should not worry.

    But damn, that marble sure sounds like a marble. :(


    Tow to garage, buy a stethoscope: Midlock automotive stethoscoop | Test en diagnose gereedschap | Autogereedschap.com

    That's an unbelievable wonder! Then you get what the doctor can hear.

    Is there a oil pressure valve that doesn't like your new oil? It flippers open/closed till viscosity is more suitable for it to stay closed.....

    For a reasonance noise it's too hard.

    Unfortunately these are all 'guesses'. Youtube diagnosis are damn hard.
     
  13. MvT

    MvT F1 Rookie
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    Ok thanks for confirming Bart!

    That's was my idea too. Need to get a compression meter for that today.
    Took the rear bank cam cover off and initial look doesn't reveil anything disturbing. All nicely bathed in oil. First compression test.
     
  14. David Lind

    David Lind Formula 3

    Nov 19, 2008
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    Remove the AC belt and see if the noise goes away. I had almost exactly the same noise in my Mondial 3.2 and it was an AC idler pulley bearing. I was on the highway and didn't have time (or place) to remove the belts in sequence, so I just cut off and removed the AC belt. Presto! Noise was gone.
    Hope your solution is that simple!
     
  15. Bell Bloke

    Bell Bloke Formula 3

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    #15 Bell Bloke, Aug 22, 2014
    Last edited: Aug 22, 2014
    Yes you could do what I did and remove all the belts and start from cold.
    Also get a fine feather on a stick, remove the wheel liner and check for exhaust manifold leaks.

    Hey MvT, I'm checking in here regularly so keep us posted :)
     
  16. MvT

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    #16 MvT, Aug 22, 2014
    Last edited: Aug 22, 2014
    Gents, I'll first do a compression test before I fire her up again. I just want to rule out any valve or valve seats to avoid further possible damage. After this I am more comfortable in turning over the ignition key to make some fire in the chambers again when we can rule that out.

    My preferred supplier will have the Compression test tool arriving in the afternoon.

    The sound doesn't seem to come from the AC, but I didn't remove the belt yet nor from the waterpump. I'll do that when I have compression test rules things out. Let's hope that it is the AC afterall! however it is a bit comforting already that you have heard the same sound on your 3.2! :D

    Nice tip! I'll be hunting for my neighbour's chicken :D I'll take that test when all other are negative together with Bill's static dischargs tip.

    First things first. -->> compression testing.
     
  17. Bell Bloke

    Bell Bloke Formula 3

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    Hey, been thinking that it's probably not a valve because it goes when hot
     
  18. MvT

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    Was thinking the same that is why I drove day before yesterday (First time I heard the noise again since last year), but the sound does not go away within the time it did that day so I am not taking any chances and run the test. 75 GBP (100 euro) for the compression test set. Always wanted to have a set anyway.

    posting back in few hours. Fingers crossed!
     
  19. Bell Bloke

    Bell Bloke Formula 3

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    I'm betting on the manifold :)
     
  20. PV Dirk

    PV Dirk F1 Veteran

    Jul 26, 2009
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    These engines are very stout. I think it's important to start with the basics and more likely problems. As mentioned, cut off the a/c belt and then start engine. (saves time :D) If it is still there cut off alternator belt and then water pump belt, or remove them. My guess is that it is an accessory like others here have mentioned. These are the cheap and easy and most likely causes. And the engine should be fine for a few moments without any of the accessories, just don't take it for a long drive without the water pump :)

    If it is a rattle as suggested by some, I flush those out by getting under car when its not running and hitting a frame member with a rubber mallet in different areas. Rattles can usually be caused to repeat that way and while the engine isn't running so you can trace them. Had great luck with this method. Sorry about the anxiety this is causing but it is likely to be an easier problem.
     
  21. MvT

    MvT F1 Rookie
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    #21 MvT, Aug 22, 2014
    Last edited by a moderator: Sep 7, 2017
    Ok guys, we have some readings. Bare in mind that I did this with a cold engine so the readings will be less then that you normally would get with a nice warm engine. I will re-do this when things are normal again as I am curious what the end result will be. I guess in around the 175 to 180 range.

    Front bank from rotor to cam pulley:
    160 Psi
    165 Psi
    160 Psi
    165 Psi

    Rear bank from rotor to cam pulley:
    165 Psi
    160 Psi
    165 Psi
    160 Psi

    We can safely say that it isn't a valve or valve seat.
    Just a pic of the spark plugs after 10.000km/7,000miles. Thought you might want to see it. When I first got her and pulled them they all where black (Too rich in fuel)

    During startup you will hear the marble sound a few time bit its difficult to locate. However David and Bill might be right!

    Tomorrow I will disconnect the belt stuff. Compression test is always on my basic test list Dirk :)
    Image Unavailable, Please Login
     
  22. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
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    Perfect compression test.
    Plugs look fine, you can only really check them after a run.
    Mine were black and I mean black until I disconnected the rich mix start injector.
    Now mine starts perfect and not a black plug to be seen.
     
  23. MvT

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    #23 MvT, Aug 22, 2014
    Last edited: Aug 22, 2014
    Yup, I'm also driving around with a disconnected rich mix start injector. :cool:
    Sorry we had a power down so flashlight work.. Here a video of a compression test of the last cylinder with marble sound. Not sure if it is the manifold. Took initial look but sound is less loud in that area.

    [ame=http://www.youtube.com/watch?v=dJrGGitHWP4]Compression test - YouTube[/ame]
     
  24. Bell Bloke

    Bell Bloke Formula 3

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    Ah so you are getting the sound in the absence of combustion in the cylindar 8 area, and under cranking..
    Could it be aircon then as others have said, that's in that area.
    I can hear a knocking also, where is that coming from? I noticed it in your first clip as you shut the engine down.
     
  25. MvT

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    Not sure Bell. The marble sound is a bit overtaking to get any reference on that sound, but I hear it too. I will take off the front cam cover too tomorrow just for inspection. Also I need to replace the 4 shims I replaced earlier as the seem too tight regardless if I find something or book results. I could hear lose valves after adjusting them. really weird as they are within the specified range.
     

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