1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Vibration

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Old May 9, 2005 | 04:41 AM
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Vibration

I seemed to have developed an engine vibration at high rpms that I don't believe was there before. It only seems to be there when I go over about 5k rpms. It's not real severe, but I don't want to ruin my motor. Its a really high pitched vibration which seems to correspond to engine rpms.

The engine still seems strong and everything, but I'm afraid to take her up to higher rpms until I figure out what's going on. I'm pretty sure that the engine is what's vibrating, doesn't make a difference if the clutch is in or not.

It almost feels like the exhaust is rubbing on the frame, and I haven't been able to check this yet, but it wasn't there before and the exhaust was installed about 8 months ago.

What could cause this vibration? Thanks...
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Old May 9, 2005 | 07:34 AM
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From: va
could be the driveshaft
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Old May 9, 2005 | 07:40 AM
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Thanks for the input, but no. The vibration is consistent with engine rpms and does not change with vehicle speed. I've experienced driveline vibration before and am confident that this is not related to the driveline. Thanks...
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Old May 9, 2005 | 08:36 AM
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How long has that engine in the car ? There's a couple of different things that could be the cause of this vibration ! So, now if the engine was recently pulled or not is where i would start the process of elimination.
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Old May 9, 2005 | 09:03 AM
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Original engine, untouched with 190,000 miles on it. No oil loss or burning. Vibration is not severe, but I seem to recall that a rotary that I had before was very smooth all the way to the redline. Thanks.
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Old May 9, 2005 | 08:37 PM
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Found the problem. One of my exhaust hangers came loose allowing the exhaust to rest against the frame. Back to silkey smooth high revving once again!
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Old May 10, 2005 | 09:55 AM
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From: va
how did that cause an rpm dependant vibration?
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Old May 10, 2005 | 10:03 AM
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Originally Posted by Kentetsu
Found the problem. One of my exhaust hangers came loose allowing the exhaust to rest against the frame. Back to silkey smooth high revving once again!
got to love these easy fixes :-)
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Old May 10, 2005 | 12:06 PM
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Talking Good vibrations...

Originally Posted by pimpncuba
how did that cause an rpm dependant vibration?
If the exhaust system is not properly mounted, allowing it to rest against the frame rail (or any other solid car part) it will transmit amplified vibrations. The pulses of exhaust coming from the engine cause these vibrations in the exhaust pipes, which is why the system is mounted with rubber dampers. Make sense?
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Old May 10, 2005 | 05:41 PM
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From: va
that is what i figured would cause it, but i didn't think it would be that significant
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Old May 10, 2005 | 11:06 PM
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Yeah, it wasn't real bad, but thinking it was coming from the engine I was pretty concerned about it...
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Old May 10, 2005 | 11:37 PM
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ahhh, I have the same problem and it must be the same thing, I just installed my racing beat exhaust myself and didn't hook up some of the hangers because they were too rusted and stuff, I need to get it into a muffler shop to get them to fix the mounts up...
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Old May 11, 2005 | 12:29 PM
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From: va
when i installed my rb exhaust i didn't hook up some of the hangers and it made a kindof squeeking sound, not really a vibration
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Old May 11, 2005 | 12:42 PM
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I had that for awile before my engine blew.
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Old May 11, 2005 | 02:25 PM
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From: va
shoo, go away before you infect my engine and it blows
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