Author Topic: Vibrations  (Read 11470 times)

Offline Lit549

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Vibrations
« on: April 07, 2013, 12:12:44 pm »
Well,my 85 c10 has a vibration.Its driving me nuts.Its dropped with 4.5/6 McGauhey kit.Installed 4deg shims to match (but opposit) pinion with trans.When im in neutral i rev it to around 2000 rpm and i can feel the vibration coming in and out.Checked motor mounts and theyre good.I did have heck getting the rings to seat,one still may not be seated good idk? They are iron rings.Motor has 6k miles,trans is new rebuilt,driveline balanced..Any suggestions?? Also has all new tires,just put 255/60/ fronts and the header scrapes ground now,long tubes..New lockup converter too..

Offline gildardo01

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Re: Vibrations
« Reply #1 on: April 07, 2013, 02:17:48 pm »
maybe its misfiring or something... just a thought...

Offline Lit549

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Re: Vibrations
« Reply #2 on: April 07, 2013, 02:44:02 pm »
Ya,that may be it.I bought this engine, installed it and rings would not seat in 6k miles.Pulled it out tore it down and hit cylinders with hone,put back with steel rings..Runs alot better,lot less oil usage;but plugs are still a little dirty..

Offline gildardo01

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Re: Vibrations
« Reply #3 on: April 07, 2013, 08:28:43 pm »
when it was put together you did make sure that the ring gaps were on opposite side right? and on their correct side... 

Offline Lit549

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Re: Vibrations
« Reply #4 on: April 08, 2013, 12:21:46 am »
Well,my mechanic friend went back with it so im not sure..I was at work..It sure is frustrating though..

Offline Blazin

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Re: Vibrations
« Reply #5 on: April 08, 2013, 06:51:40 am »
Harmonic balancer? Torque converter out of balance?
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Offline bobcooter

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Re: Vibrations
« Reply #6 on: April 08, 2013, 10:19:58 pm »
Harmonic balancer? Torque converter out of balance?
X2 on these things. Check the fan clutch also.
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Offline gildardo01

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Re: Vibrations
« Reply #7 on: April 08, 2013, 11:00:07 pm »
Harmonic balancer? Torque converter out of balance?
X2 on these things. Check the fan clutch also.
just curious what makes a torque converter get out of balance? is it common for them to be bad right out of the box? by the way i was thinking maybe the wrong flexplate or balancer was put on... for example if the crank is internally balance and the harmonic or flexplate was for a external balance crank....

Offline Irish_Alley

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Re: Vibrations
« Reply #8 on: April 09, 2013, 06:37:31 pm »
correct me if im wrong but the 400 is internal balanced while the 350 is external miss matching parts will do this also
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Offline Lit549

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Re: Vibrations
« Reply #9 on: April 11, 2013, 02:38:32 am »
 Well,check balancer and looks fine.It was new with rebuild,also converter bolts are all tight.Check all plugs and its hitting fine..Also checked flywheel for cracks and it was fine..Only thing im thinking is maybe fanclutch..As long as ive known the truck(about 20yrs) i really dont think its ever been changed.I can watch pulleys and belts (and fan hub) and everything looks straight.If fan clutch was culprit,would there be any obvious wobbling??

Offline bobcooter

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Re: Vibrations
« Reply #10 on: April 11, 2013, 09:19:22 pm »
You probably can't see one wobble. It's just a thought. The way to check it is; with the engine off reach in a grab a fan blade and try to give it a good spin. If the blades barely rotate, it's good. If the fan free wheels around then your clutch is bad. It should be pretty stiff and the blades barely move  when you try to spin it.
'79 C-20, 350/400, 3:73 gears, 9 leafs and a headache rack
Favorite Quote, "Good judgement comes from experience. Experience comes from poor judgement."

Offline Lit549

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Re: Vibrations
« Reply #11 on: April 14, 2013, 12:55:50 am »
Guess im gonna replace the fan clutch tomorrow and see what that does.Been trying to hold off to do a electric fan setup..Guess we'll see.

Offline Lit549

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Re: Vibrations
« Reply #12 on: April 14, 2013, 05:11:50 pm »
Done the fan clutch and still has the vibration..
« Last Edit: April 15, 2013, 01:22:54 pm by Captkaos »

Offline bobcooter

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Re: Vibrations
« Reply #13 on: April 14, 2013, 07:54:34 pm »
Sorry...  :-\
'79 C-20, 350/400, 3:73 gears, 9 leafs and a headache rack
Favorite Quote, "Good judgement comes from experience. Experience comes from poor judgement."

Offline gildardo01

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Re: Vibrations
« Reply #14 on: April 14, 2013, 10:39:53 pm »
are you sure the balancer was for the crank you currently have?