question for turbo experts

[camcojb]

I'm trying to absolutely pinpoint the cause of the smoke. I suspect it's still from the turbo. If you drive around it's fine but smokes on one side only at idle when fully warmed. As soon as you take off again it quits.

I let it idle until it started smoking, and then brought the rpms up to 2000 rpms or so, and the smoking stopped. What I'd like to do is rig a 1/4 turn gate valve in the oil line for that turbo. Get the car up to temp and smoking at idle and shut off the oil for a brief period.

These are water-cooled ballbearing turbos. I cannot imagine shutting off the oil for 20-30 seconds at idle could possibly kill the turbo, but that's the only way to absolutely verify that the oil is coming through that turbo.

Any thoughts from someone who knows more than me? I won't drive the car with the oil shut off, just idle only for 20-30 seconds; that should be enough to make the smoke stop at idle if this is the cause. If it doesn't then it has to be coming from the engine. This is the only way I can think of that will tell me yes or no; I need to cut the oil off immediately while it's smoking to see if stopping the oil stops the smoke. Anything like shutting it off and removing the turbo, etc. takes too much time and effort and it'd have to run a long time to get it back up to temp.

Jody

[lil427z]

jody your in take manifold runner is not sealed .
rick k

[camcojb]

Originally Posted by lil427z

jody your in take manifold runner is not sealed .
rick k

How would that suck oil on an LS2?

Jody

[lil427z]

thats right . gen 1 are different than ls 1. 2 . 7 s. do a leak test .
rick k

[camcojb]

Originally Posted by lil427z

thats right . gen 1 are different than ls 1. 2 . 7 s. do a leak test .
rick k

already did. 5-6% all four cylinders cold. Plugs are spotless. I'm just gonna try it, don't think it could possibly hurt it with no load, it'll still have oil in the bearings.

Jody

[Joel145]

Jody, have you tried switching the turbos from side to side. If the smoking changes side then you can rule the turbo as a cause. Another thought, could you possibly still have enough oil from the last turbo to still be burning off. Hope you get it sort it out. I would try to swap turbos before you attempt to run the turbo without oil.

Joel

[Steve1968LS2]

Originally Posted by Joel145

Jody, have you tried switching the turbos from side to side. If the smoking changes side then you can rule the turbo as a cause. Another thought, could you possibly still have enough oil from the last turbo to still be burning off. Hope you get it sort it out. I would try to swap turbos before you attempt to run the turbo without oil.

Joel

I imagine he would rather avoid the work involved in playing "musical turbos" lol

I can't imagine a few seconds hurting the turbo bearing, especially since they are water cooled bearings. But I'm no turbo bearing expert.

[camcojb]

Just went outside and ran the car at idle until it warmed up and started smoking. Took some vise grips and closed off the oil supply line to that turbo. Within 5-10 seconds the smoke drastically reduced, and in about 30 seconds or so it was gone. So I am definitely leaning towards the turbo oil being the cause, now I need to determine why.

The drain line is #10, and identical to the other side. It has a mandrel bent 90 degree fitting off the turbo and a 45 into the front of the oil pan, just under the rail. I have more 45's but there isn't clearance for that off the turbo I don't believe. Since the turbo was re-worked I don't think the issue is there.

Interesting deal, when I took the vise grips off, it takes 2-3 minutes or more for it to start smoking again. Seems like it takes that long to back up in the drain line all the way to the turbo, and then it's forced past the seal. Crimp it again, smoke stops and again another 3 minutes or so without smoke.

I've already checked the line for kinks and removed the fitting from the ATS pan, seems clear , nothing in the way of drainage. The crank turns clockwise so I'd think if that was the issue then the passenger side would be the one with a problem, if the oil off the crank was being shoved back up the drain line.

No final answer yet, but progress. Progress is good.

Jody

[slownova]

is the line to big or to small? i don't really know much just throwing ideas. when a fuel lines to big for a car it kinda foams up and gets weird could oil be doing the same?

[camcojb]

Originally Posted by slownova

is the line to big or to small? i don't really know much just throwing ideas. when a fuel lines to big for a car it kinda foams up and gets weird could oil be doing the same?

my feed line is #4 with a restricted fitting at the turbo; exactly as Precision recommends. The drain is #10, also their recommendation.

Jody