Just changed out the head gasket on my VIII, and after putting everything back together I get bad vibration in my car that is very noticeable after 3k rpms, and it gets more noticeable the higher the car revs.

My first thought is the balance shaft, but when we did the timing belt we lined everything up perfectly. Any thoughts?

 

The balance shaft can line up but still be 180* out though.

 

I tend to agree. If your having this vibration I think that it will be coming from the timing/balance belt area. Might want to take it all apart and check. And Benja is correct. Your balance shaft could be out of phase by 180* and your marks still line up correctly. Good luck.

 

As I remember, turn the oil pump sprocket till it lines up, turn again - do this six times and one will be right. You need to remove the plug in the block and insert a screwdriver to be sure.

 

Just put the mark on the balance shaft straight up and if it falls one way its right, if it falls the other its 180 off. There is a how-to somewhere on here that tells you which way it should f all. I can pretty much guarantee you its th balance shaft because I did the same thing about 6 months ago.

 

That's pretty much right on. Read through a few pages of this, and they start talking about it: https://www.evolutionm.net/forums/ev...-belt-how.html

 

Deffo balance shaft as its pretty easy to get it wrong but its easy enough fixed

 

Did you forget to tighten the motor mounts all the way tight?? Start simple Then keep looking.

 

Well of course it ended up being the balance shaft out of phase. Followed what people discussed in the timing belt how-to about the balance shaft access hole behind the turbo, and some other tricks. This tip was particularly helpful:

"To avoid having to *** around with the screwdriver hole thing to make sure the rear balance shaft is in phase, put the timing mark on the oil pump sprocket at 12 oclock. If it rotates toward the mark on the case, it's in phase. If it rotates away from the mark, turn it one full turn. This is an old DSM trick that works on the EVO too." - kjewer1

The vibration is gone!

 

Was the vibration really strong after 3k? Kinda like reving out a 4 wheeler or something.

 

Yea, it was very loud after about 3500rpm and up.

 

Looks like I will be opening the motor back up, I just did fixems car and the vibration is there....

 

I just had this same problem. The oil pump was out of phase. Line the mark at 12 o'clock and see which way it falls. Towards the marking on the case and its right....to the right and its wrong.

Symptoms included crazy vibration in high rpms and just more overall vibration.

Once I fixed it, it was night and day. Revs so smooth again...

 

Everyone else is right; balance shaft and/or oil pump.