Engine vibration
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Engine vibration
I've got a 95 Z28 that I road race. This car sees no street use. The engine has a noticeable vibration that is fairly consistent through out the rpm band. Most pronounced at idle but does seem to smooth out a little in the higher rpms - ~4000 and up. This is an engine vibration only, not drivetrain related. The car has 38K on it and was fully tuned last year, new plugs, wires etc. The engine had always been very smooth.The car ran great until I decided to do some work on it.
I had the manifold leak and front cover leak so I decided to fix both of those at the same time. The repairs went well and there are no more leaks. But this vibration started after these repairs. I was fairly careful about reinstalling the harmonic damper in the same place although I understand that this really should not be that critical. Still the vibration persisted.
Last year I had to take the car to the dealer for a tech1 brake bleed and had them try to diagnose the vibration while there. They found a procedure from GM for trying to properly position the damper. Essentially it said to sequentially reposition the damper and find the place where it worked best. They played with it for about an hour and said that was the best they could do. When I got the car back the vibration was a little bit better but it seems like it has regressed back to its former stage. It could also be that it was not really that much better at all. I was out of time and had a race to make so I just took the car back went with it as is.
The vibration is not awful but it is there and is annoying. Especially when the darn thing ran perfect before I screwed something up. I have raced the last two races with it this way and the car pulls strong and seems to run fine otherwise. I would like to get rid of this vibration though as I'm sure it is not great for the rotating parts.
The car goes back into a different dealer this week for another brake bleed and front end alignment before the second half of the race season. Thought I would have this dealer maybe take a look at the vibration as well.
Any ideas where to go next? Should I point the dealer in any specific direction or just let them have at it?
Thanks
Tooslow02
I had the manifold leak and front cover leak so I decided to fix both of those at the same time. The repairs went well and there are no more leaks. But this vibration started after these repairs. I was fairly careful about reinstalling the harmonic damper in the same place although I understand that this really should not be that critical. Still the vibration persisted.
Last year I had to take the car to the dealer for a tech1 brake bleed and had them try to diagnose the vibration while there. They found a procedure from GM for trying to properly position the damper. Essentially it said to sequentially reposition the damper and find the place where it worked best. They played with it for about an hour and said that was the best they could do. When I got the car back the vibration was a little bit better but it seems like it has regressed back to its former stage. It could also be that it was not really that much better at all. I was out of time and had a race to make so I just took the car back went with it as is.
The vibration is not awful but it is there and is annoying. Especially when the darn thing ran perfect before I screwed something up. I have raced the last two races with it this way and the car pulls strong and seems to run fine otherwise. I would like to get rid of this vibration though as I'm sure it is not great for the rotating parts.
The car goes back into a different dealer this week for another brake bleed and front end alignment before the second half of the race season. Thought I would have this dealer maybe take a look at the vibration as well.
Any ideas where to go next? Should I point the dealer in any specific direction or just let them have at it?
Thanks
Tooslow02
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squarehead
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Nov 21, 2014 08:02 PM