Announcement

Collapse
No announcement yet.

Diagnosing a bad harmonic balancer..

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Diagnosing a bad harmonic balancer..

    Last week, I was driving my 87 Buick Park Avenue coupe, when it started making a hideous noise. Some lame loser had the gall to tell me "Hey! You blowed your motor up! You ain't got no oil left!" when I pulled into a store.

    The problem was, in reality, a failed harmonic balancer. Starting in 1987 through the end of the production run, the 3.8L / 3800 engine had a rubber torsional damper in the harmonic balancer. If this rubber tears, the steel parts of the balancer will hammer against each other. This raises a TERRIBLE clatter. I repaired it today and made a video showing the troubleshooting process, repair, and a complication I had.

    The complication was possibly specific to the Park Avenue, and may not affect the A-Body cars.

    The 3.8 and 3300 engine have a balancer which can fail in this manner, so I want to post this here to share it.

    https://youtu.be/V5LpYFT4TUw



    Sincerely,
    David

    Look me up on Facebook

    #2
    You know David, I've had a couple of them make knocking noises where the rubber was not visibly damaged. But there was a definite knock on the engine especially when fully warmed up and idling at a stand still in gear. To the point to where we were pulling oil pans to inspect bearings and not finding any internal engine damage. These may have been cheap balancer replacements maybe? I don't remember seeing any brand names on them. My experience with this has been on A-Body's. And getting that old key out to replace it with a new one during install has always been such a pain. Would you happen to know if those keys are sealed into place with some sort of adhesive?

    Really good vid David.

    Comment


      #3
      Any idea why these engines seem to have such a high failure rate on the HBs? Ours even had one fail under warranty that was installed by the dealer. Would love to know if it was actually a GM part, considering so of the other things I have found.
      Jerry

      Comment


        #4
        Originally posted by Skip View Post
        You know David, I've had a couple of them make knocking noises where the rubber was not visibly damaged. But there was a definite knock on the engine especially when fully warmed up and idling at a stand still in gear. To the point to where we were pulling oil pans to inspect bearings and not finding any internal engine damage. These may have been cheap balancer replacements maybe? I don't remember seeing any brand names on them. My experience with this has been on A-Body's. And getting that old key out to replace it with a new one during install has always been such a pain. Would you happen to know if those keys are sealed into place with some sort of adhesive?

        Really good vid David.
        Yeah, that's what mine did to start with. The rubber "deformed" and allowed the pulley hub to shift and start banging. Then the rubber fully ripped....

        I've never changed the key unless there was a real reason because it also holds the timing gear in position. Just leave it. The new one will be no better.

        I ordered this one from Rock Auto. It is a "GreyWerks" brand. It was made in Korea and the quality appeared to be very high. The rubber was some sort of urethane with a nice glossy finish to it' and all the forged surfaces were nicely finished and painted.

        Originally posted by CorvairGeek View Post
        Any idea why these engines seem to have such a high failure rate on the HBs? Ours even had one fail under warranty that was installed by the dealer. Would love to know if it was actually a GM part, considering so of the other things I have found.
        It's hard to know why they failed so often. I have a theory that the large span of rubber was part of the reason. It has a lot of flex to it. Also, the A/C and other accessories put a hell of a lot of torque on that belt. It's been hot here, and I don't spare the A/C so that pulley has been carrying a load. That torque comes from the crankshaft right through the rubber, to the pulley rim.

        Look me up on Facebook

        Comment


          #5
          "I have a theory that the large span of rubber was part of the reason. It has a lot of flex to it. Also, the A/C and other accessories put a hell of a lot of torque on that belt. It's been hot here, and I don't spare the A/C so that pulley has been carrying a load. That torque comes from the crankshaft right through the rubber, to the pulley rim"

          That's better than anything I can think of! The previous owner of ours had wondered about the long term affect of the cycling A/C compressor. I do like the V5 compressor better.
          They are a unique looking HB.
          Jerry

          Comment


            #6
            Originally posted by CorvairGeek View Post

            That's better than anything I can think of! The previous owner of ours had wondered about the long term affect of the cycling A/C compressor. I do like the V5 compressor better.
            They are a unique looking HB.
            It could be harder on the balancer, since the cycling clutch is full torque when it runs, but the V5 torque demand falls off as the system stabilizes.
            Last edited by turbokinetic; 08-05-2018, 12:31 AM. Reason: formatting error

            Look me up on Facebook

            Comment


              #7
              I can see where you guys down south would have much higher failure rates on your balancer with the high demand you guys put on your A/C. Up here in Chicago I only run the A/C when necessary and front defroster during the cooler months. 80 degree summer days with low humidity I don't bother, I open the windows. But on days like today where it's 97 degrees out, yeah I crank up the A/C. And I'm keeping a close eye on the balancer as its very old at this point. The one on my car is currently 15 years old and I know the rubber is getting hard. I did hear a faint knocking at idle on my neighbors '93 Ciera the other day so we are gonna change that one before it goes any further. If these things are of poor quality they will start knocking short after a new install. The ones I used to sell when I worked at GM parts rarely went bad that quickly. Good parts are getting harder and harder to get for these cars.

              Comment


                #8
                Originally posted by Skip View Post
                I can see where you guys down south would have much higher failure rates on your balancer with the high demand you guys put on your A/C. Up here in Chicago I only run the A/C when necessary and front defroster during the cooler months. 80 degree summer days with low humidity I don't bother, I open the windows. But on days like today where it's 97 degrees out, yeah I crank up the A/C. And I'm keeping a close eye on the balancer as its very old at this point. The one on my car is currently 15 years old and I know the rubber is getting hard. I did hear a faint knocking at idle on my neighbors '93 Ciera the other day so we are gonna change that one before it goes any further. If these things are of poor quality they will start knocking short after a new install. The ones I used to sell when I worked at GM parts rarely went bad that quickly. Good parts are getting harder and harder to get for these cars.
                This is true good parts are hard to find. Search RockAuto for a "GreyWerks" branded one to get a very nice example that uses synthetic rubber (maybe urethane).

                The GM ones were similar to what I got from RA.

                Look me up on Facebook

                Comment


                  #9
                  Not seeing the "GreyWorks" one being offered at the moment. Will check from time to time and see if they re-stock them.

                  Comment


                    #10
                    Originally posted by Skip View Post
                    Not seeing the "GreyWorks" one being offered at the moment. Will check from time to time and see if they re-stock them.
                    I have the invoice here. It's listed as part number "ATP 102067" if that helps.

                    EDIT: Put that in the part number search on Rock Auto and it will come up.

                    Look me up on Facebook

                    Comment


                      #11
                      AAAaaaaaah, ATP. Okay. Gotcha.

                      Edit: okay, for mine ('93 Century 3300) it shows as ATP 102105

                      It does show that one as being a "Greyworks"
                      Last edited by Skip; 08-06-2018, 12:41 AM.

                      Comment


                        #12
                        David,

                        So this affects both the LG3 and LN3 motors?

                        Thanks!
                        Ken T.

                        Comment


                          #13
                          Originally posted by Century7667 View Post
                          David,

                          So this affects both the LG3 and LN3 motors?

                          Thanks!
                          Ken T.
                          Yes, the LG3, LN3, L67, LG7 etc. All the Buick 90 degree v6 that have a harmonic balancer.

                          Look me up on Facebook

                          Comment


                            #14
                            I am doing an oil change on my '93 Century today, I have the passenger side tire off and I see my harmonic balancer has a few spider cracks on the rubber. Doesn't look serious but you never know with these. I'm going to order one for mine when I order the one for my neighbors car. I want to have one on the shelf just in case.

                            Comment


                              #15
                              Originally posted by Skip View Post
                              I am doing an oil change on my '93 Century today, I have the passenger side tire off and I see my harmonic balancer has a few spider cracks on the rubber. Doesn't look serious but you never know with these. I'm going to order one for mine when I order the one for my neighbors car. I want to have one on the shelf just in case.
                              Oh yeah - looks like you'll be needing a replacement before long. Just be sure to order the correct one for the 3300 engine since the part number I posted is only for the LG3 3.8.

                              Look me up on Facebook

                              Comment

                              Working...
                              X