Vibration at 2100 RPM

[Jerry Clayton]

Did you get a balancer with external weight??

Have you tried putting the balance weight on the flywheel???

[mickmate]

Internally balanced.

[RICK LAKE]

mickmate If the dampener is a fluid one like the ATI ones they have to warm up the fluid so the weight can move inside the housing. I get a wicked vibration in my motor warming it up. Once everything is at operating temps, mine goes away. If it's solid that's a different story.
I know you don't want to hear the next thing but, is it possible the rotating assembly is not balanced??? Crank or a rod weight is off? I know ATI provides a service to custom balance your motor to the dampener. I know the price is not cheap.
I thought you all ready replaced the clutch?? Go and get a cheap auto-zone 11" reman clutch and throw it on the car and retest. Wish you where closer. I have a new zoom Z clutch. problem is a GM bolt pattern. Re drill the flywheel to fit. Rick L.

[mickmate]

It is a Fluidamper, I warmed it up yesterday and it does the same thing. We've been keeping the car running and going to events. The original clutch has been removed, balanced and reinstalled. We're planning on putting the new clutch in next week. The Fidanza flywheel bolt pattern is different to the FE flywheels I have so it probably is GM.

[Jerry Clayton]

Just exactly what facts do you have about the way the engine was originally balanced?
have you talked to the balance person and requested a job card or got the numbers/info?? Was it balanced with the flywheel and dampner that you have?? Do you have the info on the crank????If you can get this info to me I can probably guide you out of this mess---

[Z-linkCobra]

Have you pulled the pan on the motor? I dont how they balanced the crank but if they added weight could one of the weights have come off? At this point I think you have gone past the point of the clutch and all that. I think pull the pan and give a good visual inspection. Make sure there aint nothing floating around in the pan thats supposed to be attached to the crank.

just for S%*ts and giggles...do a compression test on all 8 cyls if its not too much trouble just to make sure.

Just some thoughts.

[Jerry Clayton]

10 to 1 that this is a case of wrong dampner/flywheel combo

any takers?

[Z-linkCobra]

Originally Posted by Jerry Clayton

10 to 1 that this is a case of wrong dampner/flywheel combo

any takers?

According to him...he had the flywheel checked and it was 0. He replaced the dampner with a fluid dampner. Wouldnt you think that would cover it?

I think its internal at this point. i could be wrong...I am on my second marrige..I have been wrong before..lol.

[mickmate]

Motor is a Shelby engine balanced by their engine shop. This flywheel and clutch were not on the engine when it was balanced, run and dynoed. The clutch needed quite a bit of balancing according to my local balancing shop. It needed a very small amount on the flywheel. Engine clutch and flywheel supplier all told me they are zero balance and they can bolt together fine. I asked if the parts all needed to be balanced together as an assembly and was told no. After I had the problem the story changed to "we recommend everyone balance their clutch flywheel assemblies".

[Z-linkCobra]

So with balancing the clutch and flywheel together did that halp any? Or are you still working on putting back together?

Nevermind...went back and read your previous post about balanced and put back.

Run a compression test and drop the pan...it might tell you something might not..but at least you can eliminate that.

[mickmate]

Had to report in here that it's fixed. The clutch and flywheel balancing helped, the fluidamper helped more. It was still there quite distinctly but only under heavy decelleration of the motor or the car. After deciding most of it was coming through the car (steering wheel) and not the drivetrain (shifter handle) the torque side in this case is the drivers motor mount. I previously had an alignment issue with the drivers side pipe which I corrected but it took cutting and realigning the muffler to the collector. I undid the sidepipe mount and it immediately became apparent that was the problem. I have installed fibre washers on all the metal to metal contacts and bolted it loosely through with a nyloc. FIXED! Thanks all for your help and suggestions.