Author Topic: turbo: shaft play, low boost, oil leak questions (Read 2722 times)

flapjack · « **on:** August 06, 2008, 10:20:45 am »

2.5 downpipe, 2" exhaust, new injectors, T3 , stock everything else
My T3 turbo won't give me more than 9 psi and barely 1000 deg F. I increased the fuel less than a 1/4 turn, and moved the pin and now it gives me 10 psi, 1250 deg F and smoke. Not a tire fire, but enough that if I was driving behind myself , I'd be annoyed.

I take off the turbo thinking maybe the wastegate isn't closing
First thing I see is drops of oil in the duct from the turbo to the intake manifold. (Valve cover vent isn't hooked up.) Based on some other threads , I'm guessing it's because I used a modified oil return line for a k14. I'm planning on getting a 1/2" line made the right way to replace it.

The shaft has some play, not enough for the impeller to hit the housing.

The turbo is probably from an early 90's saab, may have been beaten on by the kid who sold it to me, I have no idea.
How do you know when there is too much shaft play? Is there a way to measure it?
Anyone have a guess as to why I can't get more boost?
Thanks

foxracer1 · « **Reply #1 on:** August 06, 2008, 02:19:40 pm »

You say the turbo is off a sabb? Not the factory T3? Maybe its a little different?

flapjack · « **Reply #2 on:** August 07, 2008, 06:03:51 am »

its the same , just different flanges

jimfoo · « **Reply #3 on:** August 07, 2008, 07:09:00 am »

You did adjust the wastegate didn't you? Oil can be coming from it due to seals, so it may not necessarily be a drain issue, though it may.

jtanguay · « **Reply #4 on:** August 07, 2008, 09:16:02 am »

if the drain isn't 90 degree's or pretty damn close, it could well have a drain issue.. or maybe its plugged up a bit??? the pressure from the oil feed is not going to push the oil out the drain, although it might a little bit, the turbo will have to be full before it starts to push down the drain.. but by that time it will also be pushing out your seals etc... it's only a small amount of oil that gets 'sprayed' into the turbo to help cooling and for lubrication.

flapjack · « **Reply #5 on:** August 07, 2008, 03:34:58 pm »

Drain is vertical. Off the drain flange is a 90 deg turn to horizontal. Thats where the k14 line was hooked up.
In either case, Whether the oil is leaking due to bad seals or poor drainage, would it point to something that could affect its ability to give me more than 10 psi?
I can't think of anything besides the wastegate not sealing that would keep the thing from spinning.

Dirtrag2 · « **Reply #6 on:** August 07, 2008, 06:45:59 pm »

did you try a boost controller? place a 5$ fuel valve for a lawmower or such in the rubber line between turbo and wastegate. my t3 spools up to 25 psi no problem. even on a stock exhaust :shock:

flapjack · « **Reply #7 on:** August 07, 2008, 08:00:56 pm »

No bov & the wastegate was held shut by a rube goldberg of cable and screws. There was no slop, I checked it, yanked on it, no play in the lever on the turbo. I checked the intake duct, tightened the clamps, had it off completely, went thru each joint and put it back
The turbo flange face that mates to the exhaust manifold doesn't show any sign of leakage. I didn't check the head/exhaust manifold connection for soot.

If oil backing up thru the seals doesn't keep the turbo from spinning properly and if shaft play that stops short of the impeller hitting the wall doesn't keep it from spinning properly, then it has to be a leak I missed.