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Discussion Starter #1
my wagon has a 250ci six and when I rev it up to what I think is about 3000rpm (no tach) it vibrates like all hell. It also does it at high way speed. what could it be? F'd up flex plate? harmonic balancer? something a little more simple :pray: other than that it runs great. I drive it to work every day 20 miles round trip.
 

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check your motor mounts, they crack all the way through the rubber part.... last time one broke on my wagon you could see the motor move 3-4 inches as you rev'd it.....
 

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a straight six is inherently balanced so it has to be either the fan, or like you said the flexplate or balancer. Check the rubber ring on the balancer for cracks/ damage and the fan for any defects. If none checks out un bolt the torque converter and see if it goes away...
 

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the mounts seem fine. I've rev'd it while under the hood and there is no crazy movement. I guess I could rev it under load (in drive and reverse with my foot on the brake real hard) and see if she moves
 

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Discussion Starter #5
a straight six is inherently balanced so it has to be either the fan, or like you said the flexplate or balancer. Check the rubber ring on the balancer for cracks/ damage and the fan for any defects. If none checks out un bolt the torque converter and see if it goes away...
I noticed the bearing in the water pump is very worn. I can grab the fan and rock it around quite a bit.
 

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Check the firing order!

Also valve adjustment to tight?

bad torque converter?

Did you change the flex-plate? Maybe got one for a external balanced engine?

Just some ideas!

Good luck
Al
 
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