Reinstalling balance shafts?

[JRToy4x4]

I have an '87 TSi that had quite a bit of work done to it when I was in high school and not much for the past 20 years. I am slowly bringing it back to a more driveable status. 

At the time, I had an engine rebuild done and balance shafts were eliminated during the rebuild. Because I didn't do the work, I really don't know what went into their removal. 

In my older and more refined age, I'm thinking I might prefer the smoothness that they once offered. 

I still have the balance shafts in a box. If I were to reinstall them, how involved of a procedure is it?

What parts would I need for them to go back in and function?

Does the timing cover or timing chain need to come off? 

Was there anything done when they came out that's irreversible?

This is theoretical at this point, but I'd love to hear if it's possible. 

Thanks, 

Jason

[Dad]

You need more than just the shafts, There is a front support housing for the upper shaft, some bolts  etc. regardless I'm sure the parts can be found,  I myself don't like the shafts,  First thing you need to do is check if the rear bearings are in the block and they should be replaced since they can be an issue. not an easy task with engine in the car.  The front cover and oil pan will need to be removed. If none of the conn rods were replaced and perhaps balanced, I would just run it,  I have seen rod weights vary between engines up to 40 grams,  T suspect that may be why some people get heavy vibrations,    I don't even really notice any in my car, I prefer the higher oil pressure.

Dad

[techboy]

I second Dad, keep them out if the motor runs smoothly.  They are just more potential for failure.  I had balance shafts in a previous SQ that got low on oil pressure, the shaft got hot, expanded and seized in the motor trashing the whole thing.  I had to pull the motor and rebuild the whole thing.  That time I eliminated the shafts. Never looked back.

[kev]

I’ve never had a failed balance shaft in over 30 years of driving these cars. But if your engine is running smooth without them, meaning you don’t have excessive vibration in higher rpm’s, then I wouldn’t change anything.  If you rotating assembly is balanced well , you won’t notice much of a difference in adding the balance shafts.  
 

I’ve had a bad experience removing the shafts on one of my current cars. The rods/pistons were not weight matched (ie balanced) and I had excessive vibration that destroyed my brand new main bearings in under 2000 miles. I had to rebuild. I weight matched my pistons and rods but didn’t check the crankshaft and didn’t have the available funds to do so at the time. Thus, I put the balance shafts back in on the rebuild 

but, as I said, if it’s been running smooth for years without them, there really isn’t a need to reinstall them.  Even if you are going for a concours original restoration, nobody would ever be able to tell that you removed the shafts

[LizardKing]

I had an 86 that chewed and spat a bearing and oil out the side cover. I was able to make it home and ended up doing a balance shafts delete. Sold the car before I drove it so can't add anything about vibration. 

 

Like others have said, if it's smooth then why bother. 

[JRToy4x4]

Thank you for all of the expertise, the car runs alright (other than feeling buzzy at higher RPM) so I will leave them out and worry about other items on the car. 

The engine mounts are the original ones, would replacing them make any difference in NVH?