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4.9L timing chain tension adjust - Question

Discussion in 'Maserati' started by 71Satisfaction, Oct 9, 2014.

  1. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    Art
    What rotation of the "shaft-and-holed-disc" makes the timing chain tighter vs looser timing chain tension?

    Are the rotations opposite for Driver vs Passenger cylinder banks?

    (I have locked two 19mm nuts together on the shaft allowing me to rotate the shaft-and-holed disc to move the locking pin to the next hole).

    The owner's manual appears to indicate the Driver's side tension is Increased if the rotation is counterclockwise, looking at the rotation from the rear with the water pump at front..

    Correct?

    Many thanks,
    - Art
     
  2. eogorman

    eogorman Formula Junior
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    The rotation for both timing chain tensioners should be the same and for your Bora you are right it is clockwise looking from the back of the engine. It is possible that the last person setting the chain tension did it the other direction since this is an eccentric and will tighten the chain in either direction. But in my opinion and the QPORT engine book ref it is best to tighten the tensioner in the same direction as the cam chains run.
     
  3. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    OK. Thank you. And this is where my weak ability to interpret written language interferes with mental clarity...

    I interpret this as Clockwise on the Driver's side and Clockwise on the Passenger because the chains are rotating in the same direction. OK - No big deal - I will try it one notch tighter (Clockwise) and analyze the results.

    [I had tensioned the Driver's side one notch Counterclockwise and it DID make the rattle worse, which is consistent with your advice.]

    Much appreciated.
    - Art
     
  4. staatsof

    staatsof Six Time F1 World Champ
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    There is something to be careful about here.
    I made a wrench for turning that eccentric but even with that one of my cam lobes was sitting directly on top of a bucket and as soon as I moved the adjustment it snapped, the wrench popped out and sent a wave down that chain causing it to jump a tooth on the main sprocket.

    Not easy to rectify.

    So how noisy are they?

    Maybe Gene has a tip for preventing this and can elaborate on that torque specification in the service manuals? I never understood it.

    Just to scare you a bit more, Al Burtoni (RIP) once told me he sets these while the engine is running! :eek:

    My balls aren't that big but my brain is. No way Jose for me. :D

    Your car looked nice in the latest thread and this IS ideal Bora weather.
     
  5. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    Thanks Bob,

    They are noisier than this Spring. At idle when hot it's one distinct chain clicking.

    The Bora manual covers it, suggesting 1ft/lb torque on the shaft. Or bear down it, then back off five holes. Having done it a couple years ago at Dave Burnham's without that light a torque wrench, I know it'll work the way it should once I get my head around which rotation is correct. I JUST tried the clockwise rotation on Drivers side and could FEEL the tension building on the shaft, which makes sense. I tightened it only one notch and it made the noise worse which suggests it could be the main chain tensioner or the other cylinder bank. I'm returning it to its original tension and experimenting.

    Never had a cam shaft snap back or jump like you describe. I'll have to have a brief discussion with Dave's shop.

    BTW - that time two years ago, Dave and I found a QP manual where the English translation clearly stated to tension the chains With the engine running. But the original Italian said the opposite, and logical, way to do it. A typo! But we got the chains quiet and when they chattered again a month later I did my own tensioning at home and succeeded nicely.

    Somehow it's not being as easily done this time.
    -Art
     
  6. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    Well, now I'm in the rough….

    Yes, Dave Burnham confirms there is a deeper technical issue of the cam position during tensioning. A torque wrench is of no use unless the cam is set where Maserati engine manual says it should be during tensioning.

    So I am relying strictly on "relative position" of the pin - whether to advance it to the next hole in the clockwise direction, or counterclockwise to eliminate the chain noise.

    My experimentation is proving inconclusive and I hope not destructive:

    Yesterday I rotated the shaft counterclockwise (as viewed from the rear of the car) such that the pin was able to move one hole to the clockwise. This was done with reference to Fig 15 in the Owner's Manual. I felt the chain noise was worse during today's drive, but not by much. It was almost acceptable.

    Today's chronology of experiment (as the engine slowly cooled from hot) has not improved the situation:

    1.) Following the eogorman comment, I rotated the shaft clockwise to enable me to move the pin 2 holes to the counterclockwise. The chain noise is clearly worse.

    2.) I returned the shaft's position to place the pin where it was yesterday. The "much worse" chain noise continues with no change.

    I am stumped with chain noise of my own doing. @&%$#&^@&$%@#.

    Fig 15 in the manual suggests counterclockwise shaft rotation to increase tension on the driver's side.
    You all agree clockwise shaft rotation is correct for increased tension?
    I'll see what the exploded view can shed for light of the comment about chain direction by eogorman.

    Any other factors? Can the off-centric tensioner be rotated beyond its useful limit, or is that tantamount to a out-of-spec stretched chain?

    The beatings will continue until morale improves.

    Thanks,
    - Art
     
  7. 71Satisfaction

    71Satisfaction Formula Junior

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    Just had a thought - I'll remove the cam covers on the offending side and see if I can visually/manually check how the chain tension changes with shaft rotation…
     
  8. thecarnut

    thecarnut Formula 3
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    #8 thecarnut, Oct 9, 2014
    Last edited by a moderator: Sep 7, 2017
    I find this illustration from the QP3 repair manual useful. Notice that to tension the chains the tensioners are rotated towards the center of the engine.

    One thing I find that really helps is to slightly rotate the engine in the opposite direction of normal rotation just prior to making the adjustment. This seems to move the chain slack to where the tensioners are located. I put the car in 5th gear and push the it backwards just a little ... it does not take much.

    Ivan
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  9. 71Satisfaction

    71Satisfaction Formula Junior

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    Many thanks Ivan, Bob, eogorman
    That diagram and advice from you all should do the trick. I'll start there, bumping the car back a bit in 5th.

    BTW - I already Googled "4.9L timing chain tension" and reviewed a thread I myself had started here on this topic. In that case it ended in success and I memorialized it with a detailed description of procedure - but I failed to include any mention of direction-of-rotation-for-tension. My recollection of the process was correct, but it was useless to me now… LOL!

    http://www.ferrarichat.com/forum/maserati/392395-4-9l-time-saving-tips-timing-chain-adjustments.html
     
  10. eogorman

    eogorman Formula Junior
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    Ivan I believe your diagram is not correct. Both chains move in the same direction. Both chains go under the tensioning idlers and the cams all rotate in the same direction. The Bora manual is also wrong. It shows the chain going over the idler. THe fig 6 in the Qport manual is the same as the one in the Bora manual and not correct. When I adjust the chain tension I take off the cam covers and take the slack out by pressing the chain with a screwdriver. Bob is right there are a couple of positions that the chain is pressured by the cam if it is at the right angle to the valve tappet. By taking the cam cover off and taking the slack out you can see this happen if it is in that position. Once the slack is taken out then the cam tensioner can by moved and the pin inserted without any pressure on the pin.
     
  11. staatsof

    staatsof Six Time F1 World Champ
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    Having the cam covers off lets you make sure you don't have situation such as I had.
    I know it's rare but it DID happen to me.
    You don't want that.

    Now with respect to noises in general, you are aware that when cold those peculiar V belts have a nasty habit of making very metallic sounding noises. Some belt ease spray will temporarily eliminate that as a source.

    Yes the typo in the QPIII manual is well known but I wasn't kidding about Al Burtoni!

    Buona fortuna.
     
  12. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    Ivan, eogorman, Bob -
    I remain grateful for all you gentlemen's info and precautionary advice.

    There was a moment when I had my wrench off the eccentric's shaft and it MIGHT have rotated and detensioned the chain inadvertantly. I'll take the cam cover off to verify chain tension along with Ivan's 5th gear push back tip to get the cam in the right position to "unload" the chain.

    Side issues.
    1.) The reason for re-tensioning the driver's side was to eliminate a distinct chain noise. Now that I've messed up the tension on the Driver's side, the Driver's side chain noise is ADDITIONAL to the original chain noise I was trying to eliminate.

    I suspect the original chain noise, which has remained constant, is from the central timing chain. Maybe I'm losing the automatic tensioner. Which I understand is an "engine out" situation. Last I looked there are none available for sale, but they can be rebuilt.

    2.) Thanks Bob, re Noises when cold. I'll have to listen closer. Other than chain noise, I haven't been aware of "accessory noises" - cold or hot. There is one very faint gently "tinkle, tinkle, tinkle" noise I sometimes get at idle, which I once believed was the metal threaded collar on the loose end of a hanging AC hose. I fixed that loose end, but the occasional "tinkle" sound remains.

    I'm heading down to the Garage and will take precautions.

    Best,
    - Art
     
  13. 71Satisfaction

    71Satisfaction Formula Junior

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    #13 71Satisfaction, Oct 9, 2014
    Last edited by a moderator: Sep 7, 2017
    The plot seems to have thickened….

    I removed the holed disc to find this damage. Seems the face of eccentric's shaft has been slamming itself against the mating surface creating excessive play. And the more play there is between the surfaces, the more slamming there is. Not good. I'll call MIE for a replacement, if they have.

    The amount of play between shaft and disc spans 3 holes of adjustment. So there's the answer: No wonder I can't get this side's chain to be quiet, the difference betw a noisy and a quiet chain is less than 3 holes.

    Are the dynamic loads of change-in-tension on the chain such that they transfer to the tensioner's eccentric and shaft with this amount of force? Seems crazy. I would not be surprised if the damage was the noise I'm mistaking for chain noise.

    I'm going to pull the other side to compare.
    - Art
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  14. BartvanderWeiden

    BartvanderWeiden Formula Junior

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    Art,

    With the nut thightened the clampforce should be that high that the camshaft cannot turn and damage the drilled ring like it did in your case! So, thighten it properly.

    Success,

    ciao,

    Bart
     
  15. f308jack

    f308jack F1 Rookie

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    Also make sure that the surfaces are clean and true: As Bart stated above, it is clamping force between the plates, not the pin, that holds it in the correct position. IOW, it works like a clutch, and with the nut not tightened enough will divert the load and cause the damage you found.

    Best,

    Jack.
     
  16. BartvanderWeiden

    BartvanderWeiden Formula Junior

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    Jack et all,

    In the old days in Modena I learned a trick at Trally' s work shop: crank shaft at TDC and set the cams to the exact spec either by lift or with a 360 degree disc. Then take the second cam shaft bearing cap off and place a thin piece (~0,2mm) of flat copper between the cap and cam and thighten it carfully till the cam seizes. Than adjust the chain tensioner and set the cam gears on the cams. All assuming that one losened these before, the locking nuts can be nastly thight on the cams!
    Do not forget to take out the copper sheet piece when you are done!:)

    Good luck,

    Ciao,

    Bart
     
  17. f308jack

    f308jack F1 Rookie

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    Bart,

    Yes, but this method will only work when the cam-adjusters are loose as well.
    During routine maintenance chain-adjustment, normally one doesn't take all cam-covers off, although in theory one should. Btw, a piece of paper instead of copper stock works just as well. I take a sheet out of the printer, cut a 4cm long strip at a little less width than the bearing and fold it double. Works a treat.

    What a beautiful arrangement Jaguar designed for this!

    Best,

    Jack.
     
  18. staatsof

    staatsof Six Time F1 World Champ
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    Don't be sorry, very sorry. Take the cam covers off and be certain. I know I always will.

    I used the piece of paper as well and it worked just fine on that engine but I won't do that again either.

    That's because on another engine I tried the same thing and it cracked the cap!

    You don't even want to know what that involves to remedy.

    So I wonder how Art is doing?
     
  19. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    Good evening Gentlemen, all went well Friday.

    I called and discussed the critical issues with Dave Burnham and Ivan before proceeding (Thank You!).

    Following was the process:
    - Open passenger side chain tensioner disc and shaft and inspect for similar damage. No damage found. I noticed how hard the cover nut on this side was torqued down. Reinstall and torque down good.
    - Flip the damaged driver's side disc to it's clean, undamaged side and install verifying nice, snug fit.
    - Remove all spark plugs. Note they look a little rich-burning.
    - Remove driver's side bottom cam cover.
    - Put the car in 5th and push backwards until the cam lobes were unstressed and tension was removed from timing chain.
    - I observed clearly excessive slack in the timing chain. Which must mean I had indeed unintentionally detensioned the chain at some point in my previous day's work with the disc and pin.
    - Retension the chain with light torque, rotating the shaft/disc clockwise to tension.
    - Back off tension by one pin hole.
    - Insert pin, reinstall cover, torquing it down tight (the hammering damage to the disc was only partial).
    - Put car in 1st gear and roll it forwards 20-25ft to rotate engine through complete firing cycle. Used this to verify no valve-to-piston strike in case the chain had skipped any significant teeth. No interference found.
    - Reinstall cam cover, spark plugs, etc.
    - Check the current cash balance in my "car hobby" bank account.

    Fired up the engine.
    No chain noise.
    Idle is smooth.
    Let the engine warm up for 15 minutes.
    Took a short drive around the neighborhood.
    Engine runs well, no chain noise.
    Went for an hour or two drive on Saturday, everything running smoothly.
    Waiting for new disc from MIE to replace the damaged one still on the engine.

    Thank you all very much for your input.
    - Art
     
  20. 71Satisfaction

    71Satisfaction Formula Junior

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    Update on timing chain tension issues!

    - Late this summer the passenger side upper timing chain gave some noise from 4000rpm and up.
    - I tensioned the chain up to a modest torque, then backed off one pin-hole per the manual*.
    The chain still gave me some noise above 4000rpm.

    - I retensioned the chain with modest torque (just "hand feeling" it), and did NOT back it off a pin-hole.
    Chain noise is gone in all modes.

    Is this moderate amount of tension consistent with you all's methods and experiences?

    If I had to guess I'd say it was max 5ft/lbs.
    I recall Maserati recommending tension be erred on the loose side, rather than on the tighter side. Their torque spec is 1 ft/lb.

    Cheers, and Happy Winter to you all,
    - Art

    *The rotation for increasing tension on the passenger side was consistent with Ivan's engine diagram posted above.
     
  21. Quattroporte3

    Quattroporte3 Formula 3

    Nov 13, 2010
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    Good to hear of your progress, Art.


    Does that mean each side rotates inwards towards the block, or both rotate clockwise?
     
  22. 71Satisfaction

    71Satisfaction Formula Junior

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    Thanks,
    Yes. The "top" of each side rotates towards the center of the block to increase chain tension, like in the arrows on the diagram Ivan posted.
    Looking from the rear, the driver's side rotates clockwise (CW), the passenger side rotates CCW.
    Best,
    - Art
     
  23. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    Circling back to revisit my upper timing chain(s) which seem to be getting noisy again...

    - Has anyone experience with a "typical interval" for timing chain needing their tension adjusted?
    - Has anyone installed or heard of chain self-tensioner(s) retrofitted on any 4.9's?

    Cheers,
    - Art
     

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