Two turbos - so confused
OK, here's the deal:
Bought a used turbo. Stuck it on the car, with supporting mods. Worked great until we did the first power pull on the dyno, at which point we got a lot of blue oil smoke out the tailpipe.
We did a bunch of diagnosing. Compression is good on all four cylinders, no water in the oil or oil in the water, engine runs right/pulls fine, runs at the right temp, no smoke out the breather, plugs look good, blah blah blah.
So we decided it was the turbo's seals on the exhaust side having given up. Shaft play is evident, but I've had the turbo sitting on the bench for so long I don't know if it's more than it was or not.
I couldn't see smoke after I drove home from the dyno (though it was after dark and I was using a flashlight). When I put it on the ramps to pull the turbo off again, it smoked again, very clearly.
SO, I ordered a new turbo, which arrived today. Brand new, that is. Here's the issue: to my fingers, the shaft play between the new and the used feels identical!
What we know:
YES, the engine is healthy.
YES, I used the proper restrictor (.03 for a bb turbo)
The only thing I can think is that the oil backed up in the return. I know it wasn't kinked, but I've learned recently that my extra-capacity oil pan brings the total oil cap to about 4.5-4.75 quarts, NOT 5 quarts as I originally thought; however, I've continued to pour 5 quarts in because it never caused an issue with the stock turbo.
I'm wondering if the oil level in the pan is just too high, is pushing the level in the turbo drain too high, and the oil is getting past the seals as a result.
Any input gratefully received. I'm stumped. My tuner guy is coming over tonight to check out the two turbos and render some kind of opinion, but I'm not certain what to think right now.
Bought a used turbo. Stuck it on the car, with supporting mods. Worked great until we did the first power pull on the dyno, at which point we got a lot of blue oil smoke out the tailpipe.
We did a bunch of diagnosing. Compression is good on all four cylinders, no water in the oil or oil in the water, engine runs right/pulls fine, runs at the right temp, no smoke out the breather, plugs look good, blah blah blah.
So we decided it was the turbo's seals on the exhaust side having given up. Shaft play is evident, but I've had the turbo sitting on the bench for so long I don't know if it's more than it was or not.
I couldn't see smoke after I drove home from the dyno (though it was after dark and I was using a flashlight). When I put it on the ramps to pull the turbo off again, it smoked again, very clearly.
SO, I ordered a new turbo, which arrived today. Brand new, that is. Here's the issue: to my fingers, the shaft play between the new and the used feels identical!
What we know:
YES, the engine is healthy.
YES, I used the proper restrictor (.03 for a bb turbo)
The only thing I can think is that the oil backed up in the return. I know it wasn't kinked, but I've learned recently that my extra-capacity oil pan brings the total oil cap to about 4.5-4.75 quarts, NOT 5 quarts as I originally thought; however, I've continued to pour 5 quarts in because it never caused an issue with the stock turbo.
I'm wondering if the oil level in the pan is just too high, is pushing the level in the turbo drain too high, and the oil is getting past the seals as a result.
Any input gratefully received. I'm stumped. My tuner guy is coming over tonight to check out the two turbos and render some kind of opinion, but I'm not certain what to think right now.
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