Whats common cause for a stock LS1 to have a vibration???
09-16-2011, 08:43 PM
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Whats common cause for a stock LS1 to have a vibration??? Bought this 98 TA a few weeks ago and the motor has a vibration to it. Changed plugs and wires, swapped out the trans mount, motor mounts seem good. Yet it has this vibration in the rpm's. Even has a slight shake at idle I can feel from in the car. Does not seem to have any sort of noticable miss either. When looking I can almost see kinda a ever to slight wobble on the crank pulley when compared to how smooth the others spin. It does have an aftermarket clutch in it, wondering if someting there coulda been installed wrong and cause this? It's the same if the clutch pedal is pushed in or not. Car runs like a top and has EXCELLENT oil pressure for an LS1 let alone one with 147k on the clock. Doesnt hardly consume any oil either. I did a few hard runs in it and it held up just fine so I dont think anything is about to blow up...knock on wood. Any thoughts welcome.
09-16-2011, 09:00 PM
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See I dont have no knock and I cant see the belt tensioner causing the crank pulley to wobble at all. All the other pulleys are perfectly smooth. Only thing that comes to mind is possibly a tweaked crank snout, but seems HIGHLY unlikely...
09-16-2011, 09:23 PM
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09-17-2011, 11:39 AM
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Just had someone brake torque the engine and I watched the movement of the engine. Didn't move but maybe an inch side to side and I think the vibration is the engine itself. Motor mount couldn't cause the harmonic balancer pully to wobble just a bit
Last edited by HottLS1Z; 09-18-2011 at 07:19 AM.
09-17-2011, 10:06 PM
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Yeah talked to one of my friends tonight and showed him, he used to work for GM in the shop and said they have seen them slip on the hub more so on m6 cars then a4's and he is pretty sure that's what happened that and the vibration would be caused by this. Also I guess there is rubber in them that can crack and wear out over the years and throw it off too, so gonna work on getting that underdrive pulley put on in the next couple days. Hope this fixes it and there hasnt been any severe wear to the main bearings from it....guess time will tell!
