86' 6.2 3 groove rubber dampened Balancer

[Massboy]

I have a question on my harmonic balancer. I have the 3 groove rubber dampened pulley balancer that has a 4 bolt pattern. I understand it was put on the 86' and up engines to help prevent belt oscillation. My problem is when installing the torque converter bolts my brother went to turn the motor by the pulley with his hands. The pulley will turn, with a lot of effort on the rubber without turning the crank. The rubber all looks in good condition and doesn't appear to be deteriorated in anyway. I'm curious if this is how it dampens the oscillation or if it is bad. I will be running AC and need the 3 groove pulley but understand I could just run a hard mounted 3 groove pulley. Will it slip trying to turn all the belts? Not sure if the motor will have more noise under the hood going with the non-dampended pulley. This will be a everyday driver that the wife will drive and it needs to be as quiet as a 6.2 can be. I know, that's kind of an oxymoron. What 6.2 is quiet?

 

[brian wafer]

it should be replaced ,not supposed to turn .

 

[black dawg]

mine wont turn, and I have had both style pullies with no sound difference.

When a 6.2 is timed right, they can actually be pretty quiet.

 

[Massboy]

Pulled my pulley off the motor to inspect. Found that the pulley, though set in rubber, can only move slightly until the metal part of the pulley comes in contact with the bolt lug area which bolts to the harmonic balancer. I located a guy who's worked for years on diesels including the 6.2 and asked him about the pulley. He said he remembered most of the pulleys all moving on the hub. He believes the reason for it is when you shut off a diesel they stop abruptly and this pulley allows the momentum of the belts, pulleys, and all attached to coast slightly. This system is intended to help prevent belt stretch which in turn leads to loose and slapping belts, common on the earlier, hard mounted pulley 6.2's. It sounds logical to me. I have some pictures of the pulley to help illustrate and I will try and get them up.