760 Tell me how badly I've ****ed up- some T3 questions

Afternoon t-bricks, hope this nonsense finds you well.

I've had the stock T3 from my '85 760 off the car to do the exhaust manifold gaskets, install a flexible drain line to a shiny new Yoshifab block fitting, and some other sundry items on the exhaust side of the engine. I got everything back together, fired it up and it was leaking oil like crazy from the bottom of the turbo. I took it all back off and inspected. The hydraulic -AN line I had made up for the drain had a distorted mating surface inside, which wasn't helping so I installed the following-

ATP T3 drain flange to -10AN fitting adapter, installed with provided studs, gasket, and copper nuts

Unfortunately I realized too late that the studs have a long side and a short side. The short side of the studs is supposed to thread into the turbo. I instead installed the long side of the stud into the center section. I was finally able to get them both removed and new studs installed in the correct orientation, but that leaves me with three questions as I get it ready to go back on the car:

1. Is there anything in the center section that would be damaged by me installing studs that were 3/4 inch longer than intended? Oil passages that I may have damaged, etc? I looked at a diagram of an oil-cooled T3 but I can't really tell.

2. How do you clean out a turbo that has been off the car for a month or two? The oil feed/drain holes have been blocked for that time, but I've done a lot of cleaning of the turbo/manifold assembly including grinding off a stuck wastegate actuator bolt, and I want to make sure I'm not going to kill my turbo because I was too lazy to flush it before re-installing.

3. The stock oil feed hard line is still on the car. The T3 doesn't seem to want to fit in the car unless the hard line is bent slightly, then bent back and bolted to the turbo. I don't like this very much. Is this a place I need to be concerned about fatigue either in the line or with the copper washers that seal the banjo to the block?

I am probably overthinking all of this, but I figured it wouldn't hurt to get input from folks who know more than I do.

brickborg said:

1. Is there anything in the center section that would be damaged by me installing studs that were 3/4 inch longer than intended? Oil passages that I may have damaged, etc? I looked at a diagram of an oil-cooled T3 but I can't really tell.

2. How do you clean out a turbo that has been off the car for a month or two? The oil feed/drain holes have been blocked for that time, but I've done a lot of cleaning of the turbo/manifold assembly including grinding off a stuck wastegate actuator bolt, and I want to make sure I'm not going to kill my turbo because I was too lazy to flush it before re-installing.

3. The stock oil feed hard line is still on the car. The T3 doesn't seem to want to fit in the car unless the hard line is bent slightly, then bent back and bolted to the turbo. I don't like this very much. Is this a place I need to be concerned about fatigue either in the line or with the copper washers that seal the banjo to the block?

Click to expand...

1. No - you didn't hurt anything inside the turbo. The bolt holes in the oil drain flange don't pierce the internal oil drain cavity. I would just make sure the threads are still OK, maybe chase them with a tap, which will help clean old junk out anyway.

2. The real answer to getting a turbo completely clean is complete disassembly, sandblasting, pressure washing, reassembly, and re-balancing. A turbo rebuild shop could do this for you, but at that point you should also replace bearings and seals. But - if your oil inlet & outlet have been plugged securely, then you should only be concerned about contamination inside the compressor & turbine housings. Remove the housings, flush them out with solvent and blow-dry with compressed air. Carefully clean the compressor wheel and backplate with solvent and compressed air. Turbine wheel could be cleaned with a wire brush, as well as the interior of the turbine housing. Then blow out with compressed air. Reassemble and enjoy.

3. Make gentle bends in the stock oil line using a manual tube bender if you are concerned with kinking the tube. There shouldn't be any major concern about fatigue in the line during operation regardless, but nice smooth gradual bends will minimize any chance of kinking or cracking during the modifications. No concern about copper crush washers or banjo fitting as long as your modified line doesn't put any preload or bending moment on the banjo when installed. In other words modify the hard line such that it falls into place without the banjo fitting installed.