Turbo rebuilding / balancing question.

[nelson8708]

i recently rebuilt my Holset H1c turbo. I bought a oem holset kit and installed new bearing, seals, and all the other goodies included in the rebuild. I index the turbine fan to the center section and i index the compressor wheels to the backing plate. However i forgot to index the backing plate to the center section and because of that i sent it off to get balanced. When i got it back they had drawn a line from the turbine shaft across the compressor nut to the compressor (see pic). My question is does the compressor nut have to be inline? Once i installed everything and torqued the compressor nut down it was off by about 45 degrees. I am not sure what is more important.....the compressor nut torqued to factory spec. or to keep it inline with the balancing mark?



-Nelson

[WDRacing]

I have a lot of experience with balance and vibration analysis. The one thing I can tell you is either have it balanced by a pro, or it doesn't matter...lol. Unless it's put together exactly like it was balanced...and I mean exact, then the balance is off. The lack of balance will shorten the life of the bearings/bushings. But they can be rebuilt again at a later date if and when they go bad. The level of vibration will be different in every scenario, so it's basically a crap shoot when rebuilding a turbo. I however have rebuilt several with no issues. As have many others...

In short, I would concentrate on the torque specs since that is more critical in my opinion. Having a compressor wheel unass itself is always ugly...lol.

WD

[nelson8708]

i had it balanced at a diesel performance shop. They took the time to clean the wheels and bearing surfaces. They said the shaft was in good shape and there was no major scoring on the bearing surfaces. I was kinda torn between the torque spec and having the nut line up but, like you said if that sucker comes loose under boost it wont be pretty. When i assembled it i went ahead and torqued it to spec so i will just leave it as it is. Took me probably 4-5 tries lining up the turbine shaft to the compressor fan just right.

next time i will make sure to index the backing plate to the center section ....save me some money and a piece of mind

Thanks WD