Vibration after open track with FFR

[mj_duell]

Originally Posted by Roscoe

Could you have simply thrown a weight off one of your front wheels???

Rosoce

Hi Roscoe,
I thought of that, but I assumed the vibration would be still there even with the clutch disengaged. The vibration stops with the clutch pedal down.



--Mike

[CobraEd]

I would check the ring on the harmonic dampner behind the front pully just to be sure. If it is loose, it will cause very bad vibrations that change with the RPM.


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[mj_duell]

Originally Posted by CobraEd

I would check the ring on the harmonic dampner behind the front pully just to be sure. If it is loose, it will cause very bad vibrations that change with the RPM.
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I'll check that out as well. I was wondering.... I beat the car up pretty good all day, what are the odds the clutch cable may need adjustment or repair? Could it be hanging up the clutch slightly and causing chatter? I didn't think of this before because I do not see any slip when I'm on the gas.

--Mike

[DAVID GAGNARD]

Mike;

If the vibration stops when the clutch pedal is depressed and the clutch is dis-engaged from the pressure plate, I would have to think it is the clutch itself, or the pressure plate........outside chance it could be a problem with the flywheel.....

I would pull the trans and check this out before running the car much more.vibrations don't usually go away on their own and can and do lead to other problems down the line....if the vibration is severe enough, it will eventually cause other things to work their way lose and cause more problems...

also, check out the pilot bearing in the end of the crank while you have things apart.....

My guess, is the clutch disc itself may have lost some of it's material and throwing things out of balance, just my hunch.....

David

[mj_duell]

Originally Posted by DAVID GAGNARD

Mike;

If the vibration stops when the clutch pedal is depressed and the clutch is dis-engaged from the pressure plate, I would have to think it is the clutch itself, or the pressure plate........outside chance it could be a problem with the flywheel.....

I would pull the trans and check this out before running the car much more.vibrations don't usually go away on their own and can and do lead to other problems down the line....if the vibration is severe enough, it will eventually cause other things to work their way lose and cause more problems...

also, check out the pilot bearing in the end of the crank while you have things apart.....

My guess, is the clutch disc itself may have lost some of it's material and throwing things out of balance, just my hunch.....

David

Hi David,
I was afraid someone would say that. Tonight I checked the balancer, driveshaft, engine mounts and tranny mount as well as clearances. Nothing wrong. That seems to leave me with the inevitable. One thing I did find during my search is that I have lost a header bolt on the driver’s side and a few others were loose. I was unable to fire up the engine to see if that had any effect because of the time. I’ll give it a check tomorrow. I have sworn off any new thrashings of the car until I get the problem fixed.



Thanks,

Mike

[DAVID GAGNARD]

Mike;

Loose header bolts,especially on aluminum heads is very common......I've lost track of how many came out on my car......that should not have any effect,except maybe blowing a header gasket now and then....Usually after every two or three track sessions,once the car cools down,I run a wrench on all the header bolts,after two or three times doing that you should be o-k, but keep checking them......

I've seen some clutch disc's loose a piece of material before, sometimes a pretty good size chunk can come off and then it will throw things out of wack, also,if your pressure plate is the type with the weights on the "fingers", you could have lost one or more of the weights and that will definetly throw things out of balance...

I know it's a pain to pull it down, but it's better to do that then have something else vibrate loose and tear up.......

At least you did not find pieces of oil rings on your oil drain plug like I did this weekend!!!!!!!!!!!!!!

One thing I've found out is that track time on a car is about equal to 10 times that amount of mileage on the street or MORE.......I spend at least one hour checking things on the race car before hitting the track each time just to make sure everything is tight and in good working order............

David

[mj_duell]

Hi David,
Yup. I know I'm headed for a tranny removal. No big deal just time consuming. I have seen cars that have never leaked or made any noise suddenly start spraying oil and back fire when I tracked them. You are correct, the track does take it's toll.......I'd never stop doing it though I always check things out before track time and between runs. I lost a couple lugs at WGI and was lucky enough to make it back to the garages. I had tightened them down before my first run that day. Taught me a very valuable lesson about checking the car every time!

I'll keep you up to date on the clutch. I won't have time to get to it until this coming weekend.

"At least you did not find pieces of oil rings on your oil drain plug like I did this weekend!!!!!!!!!!!!!!"

Bummer! Never a good sign. Let me know what you find.



--Mike

[JCoop]

Motor mounts cracked or broken...just a thought...

[RICK LAKE]

Carmine What dampener is on the motor? Stock, ATI, Any markings? I will still go with the clutch assembly. Pulling the trans and clutch itself would be the first place to try and locate the vibration. It could be a bad bearing in the water pump, pulley not spinning true on the crank, If this problem just started I would stay with the clutch and flywheel first. Rick L.

[JCoop]

The reason I thought motor mounts is because for the longest time, my SPF BB would break the RH sidepipe mounts and vibrate at around that same RPM; whether driving in gear or in neutral at rest. The 3rd time I welded the mounts, I decided to change the motor mounts to poly (from Dennis O.) and haven't had a problem since. Didn't even realize it but the original rubber mounts were cracked from "spirited" revving and driving.

Worth a check, anyway. Cheers and good luck!