Engine rebuild, clutch swap... odd vibration
Thread Starter
Melting Slicks
Joined: Jul 2005
Posts: 2,586
Likes: 2
From: Bardstown Kentucky
Engine rebuild, clutch swap... odd vibration
Ok guys I have my car finally back up and running and I have an odd vibration. It does it when the clutch is pressed in so I am terrified that its an imbalance in rotating assembly or clutch/flywheel. I am really hoping it is not one of those problems but I spoke to Mcleod and they are saying they balance the clutch assembly and flywheel but not them together as a unit. They said I may need to have it assembled and rebalanced. I spoke to my machine shop and they are thinking the flywheel should be neutral balanced and not causing the issue. I did notice the other day I felt it worse going into a turn. I am leaning towards replacing the engine/trans mounts and seeing where that takes me. I can tell you the vibration is most noticeable at 1800 rpms and worse when driving than free revving. At 2500 the vibration smooths out quite a bit.
What's your alls input?!
What's your alls input?!
Le Mans Master
Joined: Jul 2010
Posts: 5,954
Likes: 711
Ok guys I have my car finally back up and running and I have an odd vibration. It does it when the clutch is pressed in so I am terrified that its an imbalance in rotating assembly or clutch/flywheel. I am really hoping it is not one of those problems but I spoke to Mcleod and they are saying they balance the clutch assembly and flywheel but not them together as a unit. They said I may need to have it assembled and rebalanced. I spoke to my machine shop and they are thinking the flywheel should be neutral balanced and not causing the issue. I did notice the other day I felt it worse going into a turn. I am leaning towards replacing the engine/trans mounts and seeing where that takes me. I can tell you the vibration is most noticeable at 1800 rpms and worse when driving than free revving. At 2500 the vibration smooths out quite a bit.
What's your alls input?!
What's your alls input?!
Melting Slicks
Joined: Mar 2018
Posts: 2,502
Likes: 187
From: California
Yup could be a flywheel maybe a fly bolt busted / could be your crank wobbling ///motor mounts may be worn no telling until you start to have at it and see what u find we’re here for ya
Last edited by Speedy007; Mar 19, 2021 at 02:12 PM.
Drifting
Joined: May 2008
Posts: 1,692
Likes: 489
From: Denver, NC
Did your OE flywheel have weights? Did you replace the damper and did it have weights? LS1 is internally balanced, but on manuals, the dampers had weights added sometimes. If it's really bad, I would be looking at the OE flywheeel looking for weights.
One thing I have learned is to mark components on things like that from original install before removal if there is any chance they can be installed in a different position.
One thing I have learned is to mark components on things like that from original install before removal if there is any chance they can be installed in a different position.
Last edited by Ed Ramberger; Mar 19, 2021 at 07:43 PM.
Racer
Joined: Jun 2004
Posts: 270
Likes: 67
From: Montana
Yeah I had same thing happened to me years ago... I ended up pulling it and having the flywheel and PP balanced together, that solve the vibration...mine was only off a few grams.. Afterward I was searching and reading up about this issue on CF. Some here have tried adding weights (machined washers) to flywheel bolt(s)... add a washer to one of FW bolts and run it. If it doesn’t help move it to adjacent bolt, then try again... this method might get it close.. you can search on CF for more details on this. I think I would try that before tearing it apart again.
Last edited by robmiz; Mar 19, 2021 at 09:26 PM.
Thread Starter
Melting Slicks
Joined: Jul 2005
Posts: 2,586
Likes: 2
From: Bardstown Kentucky
Ok guys need more help! I got the car back up in the air and noticed the transmission mount was loose so I tightened that up. The shifter vibration is gone! The problem now is there is a very distinct vibration through the body of the car. I raised the car up and had someone bring it up off idle and noticed the exhaust pipes towards the back are shaking pretty excessively. When you rev the car the shake is almost more pronounced on the way down on RPMs. Its leading me to believe I have a misfire but after pulling plugs I really dont see anything off. I will say #1 and #8 plugs looked very very lean. Anyone have any experience with this type of issue?
Le Mans Master
Joined: Jul 2010
Posts: 5,954
Likes: 711
Don't really understand what you mean by by bracin Vibrationg a misfire is not a vibration to me but more of a shake . Did you make sure you strapped down the exhaust pipes and the centre of it towards the back. Are you collaborate more on the vibration
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Pro
Joined: Dec 2014
Posts: 680
Likes: 272
From: Cincinnati Ohio
I think that vibration with the clutch pushed in was what Toys4life was describing in his video. If you notice, the use of washers to balance the flywheel technique he explains at 6:50 of the video shows the clutch pushed in.
Racer
Joined: Aug 2006
Posts: 399
Likes: 82
From: Terre Haute Indiana
You mentioned a new clutch. The sound/vibration maybe clutch chatter which is expected during the break in period. My RXT did this at the very beginning and after some break in miles, it has went away. I'll add that my noise/chatter was more pronounced when starting in first gear and at a slight turn.
Last edited by JLayer; Apr 15, 2021 at 07:42 AM.
Thread Starter
Melting Slicks
Joined: Jul 2005
Posts: 2,586
Likes: 2
From: Bardstown Kentucky
Well I changed my motor mounts and fired the car up. The vibration seemed to be gone and after a day of driving its back and as bad as always. I found a spark plug that was cracked and hope that was the issue but it was not. I am going to check the exhaust tomorrow because I am hearing it rattle in the back now which leads me to believe its coming loose and maybe causing the issue. I will report back tomorrow!
Thread Starter
Melting Slicks
Joined: Jul 2005
Posts: 2,586
Likes: 2
From: Bardstown Kentucky
I am still chasing this vibration... help me out guys! I have had the car on the dyno and everything and this problem still exists. It is bad enough that it makes me not like driving the car. I have ruled out torque tube, in gear clutch pressed in, its still there. I taped a washer to the innovators west dampner and nothing changed. I pulled the belt off the blower to make sure that wasn't the issue and nothing changed. If I could just get the thing to show a difference I would at least know where the issue is. You can hold it at 1800 and the shake can be felt all through the car.
Banned Scam/Spammer
Joined: May 2007
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From: Machineguns, because I don’t compromise
Years ago I had a factory clutch come apart so I put in another factory clutch but also put in an aluminum Fidanza flywheel to help the car rev quicker.
Vibration just like you mentioned. The flywheel was supposed to be neutral balanced (advertised as such). I removed the aluminum flywheel in put the factory flywheel on after having it resurfaced. Same new clutch. The engine was smooth as glass.
So in my case it was a crap flywheel. The vibration was very slight at idle and gave a noticeable buzz in the 1700 range then went away and came back again in the 5300 range.
Currently I’m running the same factory flywheel and a McLeod RST and it’s glass smooth.
Vibration just like you mentioned. The flywheel was supposed to be neutral balanced (advertised as such). I removed the aluminum flywheel in put the factory flywheel on after having it resurfaced. Same new clutch. The engine was smooth as glass.
So in my case it was a crap flywheel. The vibration was very slight at idle and gave a noticeable buzz in the 1700 range then went away and came back again in the 5300 range.
Currently I’m running the same factory flywheel and a McLeod RST and it’s glass smooth.
Pro
Joined: Oct 2020
Posts: 529
Likes: 197
From: Columbus, MS
If you're still suspecting a miss, get an IR thermometer. Have a helper hold it at 1800rpm (since that's where your vibration is most pronounced) and take the temperature of each exhaust manifold as it leaves the cylinder head. They should all be about the same temperature, but a cold one can indicate a miss on that cylinder. Usually, you'll get either P0300 (random/multiple misfire) or P030X (where X is number 1-8 representing the cylinder where the miss is detected) but I wouldn't count the absence of any codes as gospel proof that you don't have a misfire since you have other symptoms. Getting temperature readings will help to at least rule out a miss as you continue your diagnosis.
Le Mans Master
Joined: Oct 2007
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From: Akron Ohio
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I just went through something similar. I installed a Summit 25% underdrive balancer over the winter and a small vibration showed up between 2500-3000RPM. The manual trans cars are sensitive to mass imbalances. I noticed after the fact that the OE balancer had two small holes drilled to remove weight on one side. Then the clutch hydraulics went out on track a few weeks ago and since I was forced to replace them I did a clutch as well. I got a Fidanza aluminum flywheel and a stock Luk clutch and pressure plate. Even though both clutch and flywheel are supposed to be neutral balance, I took them to a machine shop to be balanced together. They took 2.5 grams out of the pressure plate. Once installed zero vibration.
I wouldnt do all that work without checking the balance, even though they should be neutral anyway. Like I said these manual trans cars are sensitive to it. It could be either end, clutch or balancer maybe.
I wouldnt do all that work without checking the balance, even though they should be neutral anyway. Like I said these manual trans cars are sensitive to it. It could be either end, clutch or balancer maybe.
Racer
Joined: Apr 1999
Posts: 433
Likes: 39
From: Miami, FL USA
As stated above, I'd first get an IR Thermometer and make sure all cylinders are firing. If you have a code reader see if a code is being thrown for a misfire. After you rule out a misfire, I'd probably point my attention to the flywheel. Swap it with another stock one. Hope you get it sorted.