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Excessive 6.2L noise/clatter

Discussion in '1982-Present GM Diesel' started by Mikey von, Jul 16, 2006.

  1. Mikey von

    Mikey von 1/2 ton status

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    I am new to diesels and noticed my 89 3/4 ton 6.2L makes a lot of noise.

    To me, the sound is almost like something is loose or rubbing. Some have said it sounds like excessive valve clatter. This noise makes my truck louder than most older diesels. The clatter/noise is most noticeable at idle. It almost sounds like the fan is hitting the shroud, but I have checked that and it is not the case. The 6.2 also makes a loud clank when shutting off.

    The PO has removed the fan clutch and put an after-market fan on. I plan on removing that and putting a fan clutch back on. I will check the harmonic balancer then.

    Could the valves need adjusting?

    Any ideas?



    Thanks,



    Michael
     
  2. 86dieselburb

    86dieselburb 1/2 ton status

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    Dont think the valves adjust on these diesels. I am no expert, still learning. Am in the process of rebuilding one and the rockers are a shaft set-up with no adjustment mechanism of any sort.

    Have you looked at the IP timing? When I bought my truck the timing was retarded slightly. So I adjusted it so the marks lined up and it got louder.. Maybe yours is too advanced? Does it smoke alot?
     
  3. Mikey von

    Mikey von 1/2 ton status

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    I have read that the valves do not need adjusting, but I have no clue and the person who wrote it did sound for sure. Thanks for the info!

    [FONT=&quot]I have yet to look at the IP timing. I cannot get my truck to smoke at all. [/FONT]
     
  4. 86dieselburb

    86dieselburb 1/2 ton status

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    Well look at the IP timing mark. The mark on the pump and block should line up. When your facing the motor if the mark on the pump is more towards the passenger side, then it is retarded and advanced if its more towards the drivers side. Most people just keep the lines lined up or advanced a wee bit. I have mine with the marks lined up, doesnt really clatter till the upper RPM ranges.

    I read somewhere that for every centimeter the IP mark is off from the block mark, that is like 2 degrees. So you dont want the marks to be too far apart. Retarding seems to quiet the motor and lessen smoking when you punch it. Advancing makes more clankity clank and more smoke when you punch it. You really shouldnt see smoke unless you have the sucker floored.

    Definitely check the balancer they have a reputation for failing. Might want to check the balancer timing tab, (Have no idea why there is a tab there, another way to time I guess) but on mine one of the pop rivets holding it to the timing cover broke and it was hitting the balancer. Maid more of a screetching noise. I just zip tied it up out of the way.


    How many miles on your motor? Other than the noise, how does it run?
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    That would be millimeter, not centimeter :eek1: 1 cm = .393", 1 mm = .0393"

    I agree that the IP timing might be too advanced. When I first installed my rebuilt IP I had the timing too advanced and it was stupid loud in regards to clatter. It sounded louder than an older Cummins. I backed it off so my marks are almost perfectly aligned and it still sounds like a diesel, but sounds more normal. The only time it's kinda loud is when it's dead cold and the cold advance is doing it's thing. As soon as that kicks off it's pretty quiet though.

    Rene
     
  6. BKinzey

    BKinzey 1/2 ton status

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    The valves don't adjust but they can wear out. If adjusting the IP doesn't work go ahead and pop the covers off just to make sure something isn't worn out.
     
  7. 86dieselburb

    86dieselburb 1/2 ton status

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    Yeah..millimeter...sorry us Americans, we is metrically challenged.
     

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