Vibration around 1400 rpms

[pumm3l]

did a swap about nov of last year while I was at it I put in a new clutch & flywheel after everything was done I now have a slight vibration at 1400 RPMs only, did a little searching some are saying that the pressure plate and clutch could be out of balance as a set, anything else I can start looking into?

Edit:
forgot to mention I DO have it at idle, and I ONLY feel it in the steering wheel if that makes a difference.

 

[Shiroelex]

Did you mess with the harmonic balancer during the swap at all? That was the first thing that came to mind. I'd take a look at the engine while it's vibrating, and look to see if you can hear or see anything unusual, like maybe a sputtering, spark knocking, or maybe the belt hopping around. If you don't see anything unusual under the hood at the vibration RPM, then listen down by the trans, because I'd imagine if you could feel the vibration in the steering wheel, and it was coming from the clutch, you'd definitely be able to hear something.

 

[pumm3l]

yes actually I did, I actually had to remove the entire front cover of the engine because I did an explorer swap and had to use a tbird cover so I'll check that out today to see if I can see anything unusual under the hood.

 

[Shiroelex]

I guess I could say what I was trying to say more correctly. The 4.6's crank is actually internally balanced, but the crank pulley acts as a mild vibration dampener. If you happened to use a torch for some reason, to help take off the dampener, then it's shot. Don't ask, I've seen alot of weird things. I'd focus the search more around that first, and then work your way around. Good luck!

 

[pumm3l]

well I've done a bunch of testing since I last posted.

I pulled the harmonic balancer off and started the car without it on and I could still feel the vibration so I think that rules that out.

Nothing seems to be wobbling anywhere that I can see anyway, I pulled all the plugs, they seemed to be okay and regapped them all and still have the vibration. I also unplugged each COP one after another and the RPM changed every time.

Nothing is touching the steering shaft. I noticed something new though I can hear a slight chattering noise if I hold the gas steady at say 3k rpms and give it gas slightly sounds almost like a rattle noise, but I only get it while in gear if I rev up to 3k rpms in nuetural I can't hear it.

any other ideas???

 

[damacman]

Pull the inspection cover off of the tranny and see if the clutch fork is moving excessively.

 

[pumm3l]

OK I think I figured it out. After I pulled the inspection cover and everything seemed fine, my grandfather suggested that we check the motor mounts so he had me get in the car hold the brake pedal while putting the car into gear, the left side seemed okay but when we put it in reverse and tried it the engine on the right side jumped about an inch so I'm gonna buy some new mounts and replace them hopefully thats what's causing the vibration.

Quick question though checking out the fordparts.com they list front & rear mounts? When I did the 02 explorer swap I resused the mounts from my 99 GT and only used 2 (1 left & 1 right) what is the rear mount it's referring to?

 

[Shiroelex]

Got a link to that rear mount? Usually, when you hear about a rear mount, it's referring to a mount closer to the firewall, on a front wheel drive vehicle. Or, at least, that's my experience.

 

[pumm3l]

somone suggested that it's probably the trans mount here's the link:

https://www.trademotion.com/partloc...5&make=10&model=Mustang&year=2002&catalogid=1

It threw me off because it says years 2001-2004 but the the trans was changed to a 3650 from the t45 that year which makes sense.

 

[pumm3l]

well I finally got around to changing all the mounts (left, right, trans) and the damn vibration is still there. If anyone has any other ideas to help me out I'd appreciate it.

 

[QuickCapri83]

I had a bad wire once, cause serious vibration, took me a few hours to figure it out, it just so happened, I got to work on the car late, and it got very dark out, when idling I could see spark energy coming from two of the wires, they were burnt to hell, also, my plugs for some reason were causing a little vibration also....both at the same time, freakin werd, but I replaced plugs/wires and all vibration gone. And it was pretty annoying, especially under acceleration, and only at a certain rpm.

EDIT: This was on my '87 GT.

 

[the98stang]

did a swap about nov of last year while I was at it I put in a new clutch & flywheel after everything was done I now have a slight vibration at 1400 RPMs only, did a little searching some are saying that the pressure plate and clutch could be out of balance as a set, anything else I can start looking into?

Edit:
forgot to mention I DO have it at idle, and I ONLY feel it in the steering wheel if that makes a difference.

If you feel it in the steering wheel I'd bet your tires need to be balanced/rotated. It could also be the drive shaft, but I doubt that.

 

[trinity_gt]

Was about to post a thread of my own regarding a vibration. My clutch release bearing recently gave up and started making noise so I took it to a trans shop. They took it apart and found the bearing to be bone-dry and done. They also recommended replacing the clutch "since we're in there". I went and looked at the pressure plate and disc and while they looked reasonable, I reasoned "they're in there anyway" so I had them freshen it and they used a Luk clutch. Nothing fancy...I don't need more holding power than stock...

Got it back just today and the first thing I notice (well, the second thing I notice after the very-light clutch pedal) is a nasty, nasty vibration. In mine it's worst right at about 1000RPM; the whole care shakes. At higher RPM it seems to vibrate but not as badly at 1000. It's like the natural frequency is 16Hz (16 revs per second) and at 2000 I see the 2nd order harmonic, at 3000 the 3rd harmonic and so on. At 2000RPM while driving the whole car takes on something of a subwoofer character...the whole thing is vibrating just a bit, enough to notice.

This occurs in neutral -- the car doesn't have to be moving to notice it. What's clear is that this is new; the car didn't do this before.

They said they resurfaced the flywheel and the engagement is smooth so I think that went okay. But something ain't right. A resurfacing shouldn't be able to throw a flywheel out of balance that badly, if at all.

So then my thoughts turn to the clutch. Is it remotely possible the clutch isn't neutral balanced somehow? That the pressure plate isn't right? Can you bolt up a V6 clutch to a GT flywheel by accident? (This goes to the very light pedal feel compared to my OEM Ford clutch...maybe they inadvertently gave me a V6 clutch?)

Dammit. The thing's going back in a day or two for exploratory surgery (and I won't be driving it for fear of beating the rear main bearing all to hell) but I'd like to have some tips or thoughts before it does: How can a simple clutch replacement cause such a bad imbalance to occur?

 

[sjrtx]

I replaced my clutch recently, and got a pretty bad vibration (side to side). It was pretty bad between 1k-2k rpm. If you opened the door you could see it jumping up and down.

I had put in a new King Cobra clutch and had my centerforce billet steel flywheel resurfaced. It vibrated from the minute I cranked it up, in neutral.

Took it back apart, had the flywheel resurfaced again and had it balanced. Car no longer vibrates...

 

[trinity_gt]

I replaced my clutch recently, and got a pretty bad vibration (side to side). It was pretty bad between 1k-2k rpm. If you opened the door you could see it jumping up and down.

Sounds like what mine does. (Open) doors and dash definitely move visibly at 1000RPM.

I had put in a new King Cobra clutch and had my centerforce billet steel flywheel resurfaced. It vibrated from the minute I cranked it up, in neutral.

Took it back apart, had the flywheel resurfaced again and had it balanced. Car no longer vibrates...

So after resurfacing you the flywheel balance checked out? Presumably, they added or removed mass somewhere to get it right again. Do you have more details of what that entailed?

 

[sjrtx]

Sounds like what mine does. (Open) doors and dash definitely move visibly at 1000RPM.



So after resurfacing you the flywheel balance checked out? Presumably, they added or removed mass somewhere to get it right again. Do you have more details of what that entailed?

When he resurfaced it the first time, there was a low spot. It took .012 to get it flat. Where that metal went in the low spot I dont know(or maybe it was still there accounting for the the imbalance). But they did have to drill it similar to the way they drill a crank, two good sized dimples next to each other to lighten the heavy side.

 

[pumm3l]

If you feel it in the steering wheel I'd bet your tires need to be balanced/rotated. It could also be the drive shaft, but I doubt that.

I feel this vibration in neutural as well so that should rule out that, I keep leaning towards the flywheel/clutch but I'm trying to do more simple things first before I try to remove my trans on my back with little to no room heh. What kind of place would be able to check my pressure plate & flywheel for balance? a machine shop? My car is a daily driver so I'd need to do this on a weekend and hopefully get it all taken care of before monday rolls around.

btw I also have a king cobra clutch, but my flywheel I went cheap on so thats what keeps making me go back to it.

 

[Kilgore Trout]

When you installed the clutch did you align the bell housing? Did you torque the flywheel properly?

Q.: How do I check bellhousing alignment?

A.: The first step is to check bellhousing face runout. You are checking for parallelism of the back of the bellhousing to the back of the block. Install the dial indicator (as shown fig.1). Rotate the crankshaft and mark down the reading. Be sure to push the crankshaft against the thrust bearing for an accurate reading. Maximum runout is .010.

The next step is checking bellhousing bore runout. You are checking to see if the bellhousing bore centerline is aligned with crankshaft centerline. Reposition the dial indicator in the bellhousing bore (as shown fig. 2). Rotate the crankshaft and mark down the readings. Maximum out of concentricity is .015. If the bore runout is out of spec. install appropriate offset dowels.

Offset alignment dowels can be purchased from Lakewood.
.007 PN 15950
.014 PN 15960
.021 PN 15970

Q.: Clutch/Transmission Installation Tips For 1986 and Newer V-8 Mustangs

A.: The flywheel to crankshaft bolts must be hand-torqued to 75-85 ft./lbs. (302/351W) and 54-64 ft./lbs. (4.6L) The 10.5" pressure plate bolts must be torqued to 12-24 ft./lbs. and 11" pressure plate bolts to 33 ft./lbs. + 1/4 turn.

Be sure to use the alignment dowels in the flywheels. Pressure plate bolts and alignment dowels for the 10.5" clutch can be purchased using PN M-6397-A302. Pressure plate bolts N808969-S100 and alignment dowels D1FZ-6397-B are for the 11" pressure plate.

Evenly tighten bolts in a circular direction one turn at a time. Bellhousing alignment is crucial for proper clutch and transmission function.

Due to production tolerances of engine blocks and bellhousings, it is possible for the transmission centerline and crankshaft centerline to be misaligned. Misalignment can cause transmission gear wear, transmission jumping out of gear, driveline vibration, clutch pedal vibration, pilot bearing noise, release bearing noise or excessive clutch spin time. It may also damage the pilot bearing, transmission mainshaft bearing and clutch hub. It will also cause harsh shifting.

Before installing the bellhousing, check the block mounting surface and bellhousing surfaces for nicks, dents, paint debris, etc. These are some things that could affect the accuracy of your measurements.

 

[sjrtx]

I feel this vibration in neutural as well so that should rule out that, I keep leaning towards the flywheel/clutch but I'm trying to do more simple things first before I try to remove my trans on my back with little to no room heh. What kind of place would be able to check my pressure plate & flywheel for balance? a machine shop? My car is a daily driver so I'd need to do this on a weekend and hopefully get it all taken care of before monday rolls around.

btw I also have a king cobra clutch, but my flywheel I went cheap on so thats what keeps making me go back to it.

What flywheel did you use? To check its balance, it has to come out of the car. You can ask your local machine shop who they send their balancing work out to if they dont do it in house.

Or it might just be cheaper to go buy a new flywheel.

 

[pumm3l]

I'm using an excedy racing flywheel:

http://cgi.ebay.com/ebaymotors/EXED...hZ019QQitemZ8071407038QQrdZ1QQsspagenameZWDVW

That's the exact one I have.

I definitly torqued the flywheel bolts and in the circular direction as suggested. I didn't use alignment dowels I used this clutch alignment took from advanced auto parts, looked like a 5" long plastic shaft with ridges like a gear and and a ring on the end seemed kinda pointless the way it worked. I didn't check the bellhousing alignment, and I didn't make sure the trans center line matched the crank centerline.

I guess I'll be pulling everything apart, the bell housing alignment is a bit confusing to me though, from what I gather it's saying to check the "flatness" of the bellhousing and of the block where the bellhousing bolts up to block?