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D6T C9 valve set

Discussion in 'Shop Talk' started by simonsrplant, Sep 21, 2015.

  1. jjimbo

    jjimbo Active Member

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    I did a cam in a C9 recently dew to lift retain failure allowing the lifter to turn side ways the customer complaint was bent pyush tube on intake. What was hapenig was that the exhaust lobe failed. and it would not let exhaust gas out. Build up to much pressure and bent intake push tube.
     
  2. simonsrplant

    simonsrplant Senior Member

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    Sounds somewhat similar... Were the block lifter bores damaged by lifter failure?

    I found similar information not concisely clear as to requirements to extract the lifters... I stopped in and tried on my way home the other night. The head casting hole for push rods is just too small to allow the lifters through. It seems likely that the failure lies within the cam and or lifters are at fault. Next will be removal of the head and inspection of the lifters, bores and camshaft.
     
    Last edited: Mar 9, 2016
  3. ETER

    ETER Well-Known Member

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    Can the base be dropped and then a visual inspection done of the suspect lobes from under? I know it's not a C9, but in order to pull the cam on the Mack E7, the lifters must be held up regardless of heads on or off (the harbor freight magnets came in several hundred dollars cheaper than the Mack special tool).
    Regards, Bob DSC05322.jpg
     
    Last edited: Mar 9, 2016
  4. jjimbo

    jjimbo Active Member

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    Not in the block that I did. How ever I had to pull the head in order to remove damaged lifter. The rest of the lifters I could remove with head it place.
     
  5. jjimbo

    jjimbo Active Member

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    Great idea magnet will work in other applications also. The C9 I was working on was in a windrow turner so to get the pan of I had to pull the Engine.
     
  6. simonsrplant

    simonsrplant Senior Member

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    Bob;
    Yes I could drop the pan and look up at the lobes but I would not see the rollers on the lifters clearly.
    I've been inside an E7 not so long ago... IMO I think the build is a little backward, having to hold the lifters up to slide in the cam... I had that particular motor out and recall supporting it upside down to fit the cam...
     
  7. ETER

    ETER Well-Known Member

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    simonsrplant, have you measured your cam lift yet on the bent tube lobes? If you measure one lobe lower as compared to an adjacent cylinder (inner base), then I would say your lifter has dropped or "flattened"...if your measured lift (outer circle) on suspect lobe is low but, but correct on the inner base then it's safe to say the cam is shot (and lifter) and looking up the base (even if you have to use a mirror) would give you a visual verification before teardown.
    Regards, Bob
     
  8. ETER

    ETER Well-Known Member

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    on edit, also makes me wonder if you could (if needed) replace the cam like the E7 by holding up the lifters, drop the damaged lifters out the base (like the E7) and complete the repair without head removal if normally required?
    Regards, Bob
     
  9. Nige

    Nige Senior Member

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    TBH in a D6T installation it's probably easier to pull the head off than it would be to get at the front end of the engine in order to pull the cam out without removing the head. The cam is driven from the front gear train so to get it out would probably need either the hardnose with the radiator/aftercooler/cooler completely removed, or at the very least the rear pins pulled and tipped forward to give enough space. I recall doing the cam on a C-15 in an 834H for exactly the same fault as you have here and it needed more than a bit of creative ingenuity to get the radiator/hardnose moved far enough to make enough space to get the cam out. The dealer personnel were hell-bent on pulling the engine because that's "what the book says" until I stopped them. If moving the hardnose would work in a D6T I have no idea.

    Simon, if the cam is bad (ETER's idea of measuring the lift on the lobe where the bent pushrod is located and comparing it to the others will work) you might be just as well pulling the engine first up unless you can somehow create enough space to get the cam out some other way. If you don't you might end up expending loads of effort trying and at the end of it all end up pulling the engine anyhow.
     
    Last edited: Mar 9, 2016
  10. ETER

    ETER Well-Known Member

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    Good point Nige on expending "extra" effort for a short cut when the correct method of repair will save time in the long run...I haven't been into a C9 or this machine, so there are nuances that I am not aware of. It's just nice before the "rip and strip" process starts to have actually put "eyes on" the failure. That C15 has a very loooong cam, but at least you can inspect it easily!
    Regards, Bob
     
  11. jjimbo

    jjimbo Active Member

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    I miss spoke this morning and would like to correct what I said The C9 that I worked on I did have to pull the head to remove follower. I had to remove the cam for the damaged follower. It had turned side ways and mushroomed above the roller. The rolled pin and roller were also damaged.
     
  12. mrappels

    mrappels Well-Known Member

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    the cost of a new cylinder head gasket is probably around 100 dollars, not more than a couple hours to remove too. least for the c11 its 120 usd here, so it'd definitely not be that much to pull the head, when it'll likely give you a much better view of what's going on hey.

    the radiator group will have to come out to get the cam out i believe. there was a cam failure on the d6t at another project, just befor i qualified. i got moved there just after it broke down, it was also because the valve bridge kept jumping off. the push rods were ok, and when we set valve lash it would be in spec, it fell off twice more before the cam follower revealed itself to be the culprit. it would turn onto its low spot (i assume) and jump off, then settle on its good face and leave us confused and without an explanation. so it was sent to our workshop n fixed there. there was no SOS sampling to be heard of and only at the end did the metal reveal itself in the oil.
     
  13. simonsrplant

    simonsrplant Senior Member

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    So my plan is to pull the head and cooler group. I can inspect everything properly with it off. With the cooler group off and a majority proportion of the individual rad cores, but nose cone on, I believe I will be able to extract the cam.
    Dependant on the findings the cam may be left in place and remaining block removed for replacement.
    What effect would scoring on the lifter bores have? They are just splash lubricated roller followers, surely a "dressed" scored bore wouldn't be detrimental to longevity?
     
  14. Mark250

    Mark250 Senior Member

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    the lifter bores are pressurised with lube oil, don't forget this oil is also low pressure feed for HEUI system

    C9 lifter oil feed.jpg
     
  15. jjimbo

    jjimbo Active Member

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    The C9 that I did I also changed the HUIE pump and injectors. I have a componet shop in the area that dinos alot of engines. they told me that after a follower failure thet can not get the horse power with out changing due to the fine metal in system.
     
  16. simonsrplant

    simonsrplant Senior Member

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    Thanks gentlemen... That I was not aware of! The head is coming off tomorrow... I fear the worst for the motor.
     
  17. ETER

    ETER Well-Known Member

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    jjimbo, how do you think that "fine metal" would find it's way into the lube system after such a failure? Good luck on the teardown simon and update us on your findings.
    Regards, Bob
     
  18. jjimbo

    jjimbo Active Member

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    In the case of the engine I was on the follower turned side ways and damaged the lobe on the cam. The mechanic before me had removed the head and replace the follower. So when the follower failed again it worn more of the lobe away. So as the lobe was worn away that is where you get the fine metal.
     
  19. Nige

    Nige Senior Member

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    Without changing what...?

    Any fine particles generated by the lifter roller griding away at the cam lobe ought to be caught in the engine oil filter IMHO. I've seen a number of cam/lifter roller failures on C-series engines and can't recall a single one where the engine wasn't restored to full heatlh simply by replacing the cam and the affected lifter. As I used to monitor the oil analysis on all our engines I'd have though that if anything untoward had gone on after the lifter failure I'd have noticed it.
     
    Last edited: Mar 11, 2016
  20. simonsrplant

    simonsrplant Senior Member

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    So as expected the lifter was ruined. There was also visible wear to the cam. Only minor scoring is visible in the lifter bore.
    My question for the hallowed collective is:
    Is the minor scoring acceptable and the motor repairable by replacing the cam and lifters or does the high pressure oil system lubribate the lifters to extremes and any damage to the notes have significant effect on motor reliability.
    Pics to follow.