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Bad motor vibration over 4000 rpms... any ideas?

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Old 10-20-07, 08:56 PM
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Bad motor vibration over 4000 rpms... any ideas?

OK, so i have a stock 13B non turbo, just rebuilt about 7000 kms ago. When i'm driving it, as soon as the rpms get to around 4000, i can start to feel/hear a vibration which gets worse as the rpms climb. i don't dare rev it past 6k right now. It does this in all gears, as well as in neutral. Any ideas? maybe an air pump issue? all that has been done lately is cooling system stuff, replacing hoses, as well as the water pump. i'm not sure if it started before or after though.... any ideas?
Old 10-20-07, 09:02 PM
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Did you replace the engine mounts when you reinstalled the engine? Tranny mounts?
Old 10-21-07, 01:22 AM
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engine mounts, tranny mounts, or driveshaft
Old 10-21-07, 10:24 AM
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Is the car an auto?

Did it vibrate ever since the engine was rebuilt??

Has it been the same fromt the beginning or has it gotten worse over some time?
Old 10-21-07, 11:09 AM
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I had the same problem on my vert. So I replaced the engine mounts and the vibration went away.
Thanks Robert
Old 10-21-07, 05:23 PM
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it is a 5- speed, and did not do it when we put the rebuilt motor back in, i pulled strong and smooth all the way to redline after i broke it in. all mounts looked ok, the transmission and driveshaft i have not even touched. 182000 kms on the car. is there a possibility that it is water pump related? i'm not sure if it started before i replaced the water pump or not.

edit: and to answer your question zbrown, it doesn't seem to be getting any worse, it's like it just showed up, and isn't getting better or worse
Old 10-21-07, 05:29 PM
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Originally Posted by arghx
engine mounts, tranny mounts, or driveshaft
+1
Old 10-21-07, 06:07 PM
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i really don't think so. i think it has something to do with my water pump, or its pulley, or the fan... could it be one of those?
Old 10-21-07, 07:08 PM
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k,

the 5-speed rules out a cracked flexplate as the culprit... like i had long ago

being the vibration wasnt there right after the rebuild means that the engine wasnt assembled with an improper front counterweight or flywheel.

if the car is is in neutral not moving does it vibrate when you rev?

with the clutch depressed same question ?
Old 10-21-07, 07:37 PM
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Originally Posted by chwkrx7
i really don't think so. i think it has something to do with my water pump, or its pulley, or the fan... could it be one of those?
No. That wouldn't cause engine vibration.

More than likely what it is, is that since you rebuilt the motor, it has more power and is running correctly. You weren't on it hard it while you were breaking it in, and then once it was broken in, you probably revved it up and got on it. Your ancient mounts were probably about to go anyway, and with that extra power from the new motor just broke them.
Old 11-03-07, 01:00 PM
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i guess i should probably post the fix to the problem for future ppl to use it did turn out to be the water pump. i got a new pump from eunos (thx chris), put it in, and after some minor installation issues due to a broken bolt, it's all in, and in properly now. i did not use the washers, as once i looked at the pump housing, you could see the hieght difference where the gasket did not mount. thanks again to stef71 for coming out and lending a hand. the car has been fine now for over a week. i'm taking the fenco reman pump back to lordco today to try get my $ back for that pos they gave me.

dk
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