M50 Vibration Dampener?

[Jon K]

So I am having a vibration that I did not formerly have around 3500 rpm, and it only seems to be REAL noticeable to me when the engine is cold, after about 10 or 15 mins it seems about normal. Buddy said it could be the harmonic balancer/vibration dampener. Looking on RealOem.com, I see that they are calling the crank pulley a "Vibration dampener"!? To me, it seems the crank pulley is solid metal with teeth, how the hell, then, does it go bad?!

[SnakeyesTx]

I think if you take the face of the pulley off, there'll be balancing cuts into the steel. Once in a while there'll be a rubber section between the balancer and the outer area where the belt rides. I had this kind of setup on a Jeep Cherokee, and if the rubber works its way out, the outer rings falls off... belt comes off, and well you get the idea.

[Jon K]

I don't recall seeing ANY rubber in that area. Can someone chime in with help!? Maybe this is my issue?! Who knows!!!!

[Bill R.]

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I don't recall seeing ANY rubber in that area. Can someone chime in with help!? Maybe this is my issue?! Who knows!!!!

[Bill R.]

if the rubber in the damper goes bad then the timing locating point can move around to and the timing is altered so the car can run like crap. I don't think that is your problem. What else did you do to this engine before this happened?




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[Jon K]

if the rubber in the damper goes bad then the timing locating point can move around to and the timing is altered so the car can run like crap. I don't think that is your problem. What else did you do to this engine before this happened?

Bill the motor is currently stock. It ran COMPLETELY normal and without incident friday. Then friday night, we had the oil pan hit the crank prob (noise, metal in oil etc). That same night I did remove the crank pulley from teh face of the motor along with the AC pulley inside the crank (not in use, why have it?) and removed teh aluminum AC bracket from pass side of motor. I didn't notice any vibration but then again since the car made that noise I didn't rev much over 3000 rpm that night. Then saturday I dropped pan again, ground down the baffle, put it together, noticed the Vibration around 3500+ rpm, came back, threw the AC pulley back on hoping that had something to do with it, but didn't. So now, as it sits, I have a stock M50 with a tapped oil pan for oil return, ground down baffle, normal belt config with AC pulley bolted on but not hooked to AC (gone).

I will also note that this morning on the way to Ocean City (and this happened once before!) I started the car, and it ran like CRAP. Like, the RPMs were like 300, sputtering, not doing good things but it stayed on. I turned it off, turned it back on, and it was fine. Could be dying battery, could be something weird in my wiring harness for my standalone ECU (not installed currently) - or it could be the harmonic balancer being broken and the wheel being off sometimes? Dunno. Is there a way to check this balancer thing? When taking about my other M50 motor I didn't notice anything rubber on the crank but I also was not looking.

I have upgraded UUC Motorworks "race" transmission mounts with metal retaining cups, which can contribute to vibration but prior to friday I never really experienced any vibration... then again the oil pan being removed and what not could have let the trans settle or something? I am digging deep now... I wish this were plain as day to me!

[Bill R.]

impulse wheel and then if you look closer to the center of the balancer you'll see the grooves on the pulley where the belts ride, a little further in and you can see the thin laye of rubber that actually separates the outer portion of the assy. from the inner portion, it looks almost like a groove cut in the balancer. If the rubber is bulging out or missing in places then thats a bad sign... If its bad enough to cause a vibration then you should be able to move it with your hands if you have all the belts off the engine and grab the outer portion of the balancer. right where the teeth are for the crank sensor. try wiggling the balancer back and forth in the direction that the crank rotates, or try pulling it in and out, if you can move it in any direction without the crank moving then the damper is definitely bad.






Bill the motor is currently stock. It ran COMPLETELY normal and without incident friday. Then friday night, we had the oil pan hit the crank prob (noise, metal in oil etc). That same night I did remove the crank pulley from teh face of the motor along with the AC pulley inside the crank (not in use, why have it?) and removed teh aluminum AC bracket from pass side of motor. I didn't notice any vibration but then again since the car made that noise I didn't rev much over 3000 rpm that night. Then saturday I dropped pan again, ground down the baffle, put it together, noticed the Vibration around 3500+ rpm, came back, threw the AC pulley back on hoping that had something to do with it, but didn't. So now, as it sits, I have a stock M50 with a tapped oil pan for oil return, ground down baffle, normal belt config with AC pulley bolted on but not hooked to AC (gone).

I will also note that this morning on the way to Ocean City (and this happened once before!) I started the car, and it ran like CRAP. Like, the RPMs were like 300, sputtering, not doing good things but it stayed on. I turned it off, turned it back on, and it was fine. Could be dying battery, could be something weird in my wiring harness for my standalone ECU (not installed currently) - or it could be the harmonic balancer being broken and the wheel being off sometimes? Dunno. Is there a way to check this balancer thing? When taking about my other M50 motor I didn't notice anything rubber on the crank but I also was not looking.

I have upgraded UUC Motorworks "race" transmission mounts with metal retaining cups, which can contribute to vibration but prior to friday I never really experienced any vibration... then again the oil pan being removed and what not could have let the trans settle or something? I am digging deep now... I wish this were plain as day to me!

[Jon K]

thanks bill I am looking thru my pics now to see if I have any of it

[Bill R.]

it pretty clearly.



thanks bill I am looking thru my pics now to see if I have any of it