I just had my engine rebuilt. It has stock rotating assembly with the exception of mahle forged pistons. They installed a Comp Cam with stock valve train. They said they balanced it but it vibrates bad at 2000 rpm and gets a bit better as the rpms increase. Balancer is straight. They said a Larger cams will cause this. Any experience with this? I had the flywheel cut with a new clutch setup. Is it possible this could cause it?

 

Addressing the bold: If this isnt a stock sized cam you will run into more problems with springs and pushrods possibly.

LOL! Larger cams will not cause the engine to be "out of balance". You may need new motor/trans mounts.

The flywheel having a resurface could have something to do with it. Does it do this under a load as well as free spinning? If it does it on both I would take another look at that flywheel.

 

I does do it under a load and freewheel. It is noticeably worse under a load.

 

check your plugs, I had the same problem.. and it did the same thing. try putting it in a high gear at low speeds and step on the gas if it make a bad shake you have a bad plug.. sounds crazy but it works.

 

Sounds like it wasn't balanced correctly.