Vibration Dampner bad?

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ShagWagon
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Vibration Dampner bad?

Post by ShagWagon »

I installed a new one 8k ago or so because the rubber was sticking out when I went through a motor rebuild.

I suspect the new one has gone bad because I get vibration at around 1500rpm when in park and in drive at about 25-30mph when I feather the gas pedal.

I watch it when it spins and it seems wobbly but that might be my mind tricking me.

Any tests can do or be done to determine if it's good or not? It's somewhat new so I can't believe it would be bad out of the box.
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mx71
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Re: Vibration Dampner bad?

Post by mx71 »

Which damper? On the steering shaft, the steering stabilizer? Transmission/motor mount?
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tgreese
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Re: Vibration Dampner bad?

Post by tgreese »

I think he means the damper on the front of the engine crankshaft. It's part of the external balance of the engine, and has a built-in hard rubber layer to help dampen engine vibration.

I think the only thing you can do is remove and inspect. Pretty sure there's a source for new aftermarket dampers, and there are services that will rebuild your damper. You still have the old one? Send it in to be rebuilt, then swap it.
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Re: Vibration Dampner bad?

Post by Curly »

I had a similar thing happen on a Cadillac 390 engine I had rebuilt. The vibrations were around 1200-1400 rpm in P/N and were pretty bad in gear,right at the 2-3 shift point. My engine was out of balance due to a poor set of pistons. A different set of pistons, properly checked for weight fixed the problem.
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ShagWagon
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Re: Vibration Dampner bad?

Post by ShagWagon »

mx71 wrote:Which damper? On the steering shaft, the steering stabilizer? Transmission/motor mount?
It's vibration dampner or harmonic balancer for the engine.

I was thinking to swap out the on on my parts Jeep. Good idea? They seem to be a 50 year part.
87 Grand Wagoneer Rebuilt 360 by S&J, Fitech GO EFI 600, Novak in-tank fuel pump, Skyjacker Hydro 4" lift, BFG AT KO2 30", Dynamax Muffler, MSD distributor, MSD ignition, Edlebrock perf 4bbl intake, Elgin perf cam, Oil tube mod, Roller rockers, chrome molly lifters, HD alum radiator, Powermaster 150/100 alt, Alum HD water pump, Serhills tailgate harness, Cowl screen mod, Evil Twin grab handles, Rstep's custom AMC door lock knobs, all electrical works.
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Re: Vibration Dampner bad?

Post by Stuka »

ShagWagon wrote:
mx71 wrote:Which damper? On the steering shaft, the steering stabilizer? Transmission/motor mount?
It's vibration dampner or harmonic balancer for the engine.

I was thinking to swap out the on on my parts Jeep. Good idea? They seem to be a 50 year part.
That should be ok. I thought they differed per engine, but seems like the part numbers are the same for AMC 304/360/390/401 engines.

EDIT: I was right, they are different as mentioned below! Beware places cross selling them.
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Re: Vibration Dampner bad?

Post by Nikkormat »

304/360/401 definitely use different balancers!
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REDONE
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Re: Vibration Dampner bad?

Post by REDONE »

Nikkormat wrote:304/360/401 definitely use different balancers!
Ditto! If someone is listing the same PN for all of them, then it's either a mistake or a universal damper that requires extensive machining of the crankshaft and fly wheel to actually balance.
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Re: Vibration Dampner bad?

Post by Stuka »

Ok, that’s what I thought, but a parts search showed they were the same. But edited my post above.
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