Was putting together the center section of my soon to be new Garrett T3 turbo last night for my 300 sd... snugged the ten mm nut on the end of the shaft and gave it an experimental spin. I expected it to freewheel but instead I got only a couple revolutions out of it and I was surprised by that. I can't find anything put together wrong... is it supposed to be that firm when newly assembled?

 

I would contact the manufacturer and ask. I should think it would spin very freely!

Here is their web site...
(Contact link on bottom right)
Turbochargers | Turbobygarrett

 

I put it together using a good assembly lube. The action is smooth as silk, just not as free as I was expecting. Now these brass bearings... I thought they were bushings and not supposed to spin in the bore, but they do. The old ones measured .6178; a little wear and some light scoring. The bores are round and free of scoring and wear, but they measure .622. The new bearings are .618, which leaves .002 play per side. Is that the way it is supposed to be? Or did they give me the wrong size in my kit?

 

Awesome! Then I'm almost ready to put it back on the car. Do you or anyone else know of a way to test the wastegate and make sure it is functioning properly while I have it out? I was able to find all the information I needed to deal with the turbo itself but all I know about the wastegate is it's basic function and that there are springs somewhere beneath the cover on the back. I would like to take it apart and clean it- it would be aggravating to have a nice new turbo and no boost due to a stuck open valve- but not without a little more info.

 

Sufficient time has elapsed for me to declare my turbo rebuild a success. Thank you ForcedInduction for the tip about the journal bearings... once I knew what to look for I found all the info I needed.
However! my venerable '83 300sd still suffers from the low end power problem I've been trying to trouble shoot for some time. Not that I expected the turbo to be the issue; I was fairly certain it was not. I just started hearing the bearings whine and decided to rebuild.
Here is a list of the things I've tried...
I began by changing the fuel filters. Since changing them I see no dirt or other gunk in the primary, it looks clean and clear.
I adjusted the valves, which were in pretty good shape to start with except for the last two or three which, hmmm, are the hardest ones to get to.
I replaced the hand primer with the new model since the old one was leaking like a sieve.
I replaced all the old cracked hoses. Incidentally, what is the purpose of the cigar hose? I have regular fuel line in there for the moment. Replacing the hoses and primer pump made the engine run considerably smoother as I eliminated air leaks into the fuel system. It's still rough when it's cold, and misses a half dozen times at startup, but overall much better.
I replaced a couple weak injectors. I think I might still have one that is causing the miss at startup.
At this point I rebuilt the turbo. As I said, not expecting it to solve the power issue, but I DID entertain some hopes in that direction. On that note, I hear an air whistle from the new turbo. No leaks that I can find...?
Thinking that maybe the screen filter in the tank was clogged I swapped the intake and return hoses at the injection pump. No difference.
I read a post where someone plugged their EGR and ARV valves(don't think I have an ARV) and got full power, but for me, you guessed it, no change.
I pulled my valve cover back off and checked the camshaft timing. With the marks lined up the little arrow points dead on zero at the balancer. The sprocket looks good. There is some slop in the chain but I don't know how much is too much and wouldn't the timing be off if there was anything wrong?
I can only think of two more things, the injection pump and the mysterious ALDA. I note that the plastic cover is gone from the ALDA adjustment screw, indicating that it has probably been tampered with. Yes, I checked the banjo bolts, clean and clear.
I do NOT want to mess with it, or with the IP, but I think I've run out of options. If anyone can think of anything else?
I believe it is fuel related. If you kick the throttle wide open there is a serious delay as the RPM's slowly climb to match the throttle position. If I slow down to make a turn it lags getting back to speed, but if I downshift manually to second and keep the RPM's high I never lose power. There is plenty of power at highway speeds. I'm stumped. Please Help!

 

After a judicious amount of time I declare my turbo rebuild to be a resounding success. Also, thank you Forced Induction for your tip about the ALDA screw... two and a half turns back and I have fantastic power and better fuel mileage. Love it when a plan comes together!!