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03-30-2013, 04:56 PM
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#1 |
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Senior Member
 
Join Date: Oct 2012
Location: mountain view arkansas
Posts: 1,304
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350 vibration
I have a 84 Chevy 4x4 with a 350 auto. At idle it vibrates and when revved up you can feel it vibrate. I thought it was missing but you can put it in gear and give it gas and hold the brake and it does not miss. I replaced the plug wires and the plugs looked good. Could it be the harmonic balancer? I need it smooth because I am trying to sell the truck.
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http://67-72chevytrucks.com/vboard/s...d.php?t=548705 |
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03-31-2013, 09:11 AM
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#2 |
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Registered User
Join Date: Sep 2011
Location: Chesterfield, Va.
Posts: 339
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Re: 350 vibration
Could be the H.B., but I'd check 1 more thing before I replaced it... Run a compression test across all the cylinders and make sure they are even. It could be all 8 are firing, but 1 cylinder is way weaker than the others. For example all are 120 and one is 80, or some stuff like that. A burnt valve can act like this.
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03-31-2013, 08:44 PM
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#3 |
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78K & 79C Jimmys
Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
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Re: 350 vibration
check for bent/cracked/broken fan blades
Posted via Mobile Device
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John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350 |
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03-31-2013, 08:53 PM
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#4 |
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Senior Member
Join Date: Oct 2012
Location: mountain view arkansas
Posts: 1,304
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Re: 350 vibration
Thanks for the replies Compression was good. I slowed the timing down a little and it seemed to help at idle. The engine runs very well so it shouldn't be much.
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03-31-2013, 09:12 PM
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#5 |
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Registered User
Join Date: Sep 2010
Location: Marble Falls, TX
Posts: 1,575
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Re: 350 vibration
Just tell 'em it has a mean cam in it
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Michael Re-starting the neglected '77...http://67-72chevytrucks.com/vboard/s...=425464&page=9 |
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