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hoyabear hoyabear is offline
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Join Date: Feb 2008
Location: Seekonk, MA
Posts: 142
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I have to chime in on this one as I am still dealing with this issue. Right off the bat, it sounds like you are having a scavenging problem of some sort. If the seals were bad it would be happening fairly constantly. I went through this problem already, replaced the turbo with a new one, had the same problem again, had the new turbo's seals replaced and after putting the damn thing in again am still having issues.

I will say from experience, just because the scavenge pump appears to work once, twice or more times when you test it (using the typical test), doesn't mean that it will work every time. I found out the hard way that my scavenge pump was working intermittently, it just so happened to work when-ever I tested it (well, at least until I eventually caught it!). I have since rebuilt the pump and it works much better. However, the problem is still not gone and now the car smokes like mad whenever it decells (engine brakes).

My assumption is that there could be other issues that haven't been resolved that were probably compounding the initial issue:

1.) the car has an aftermarket drip tank that is unvented
2.) the angle at which this drip tank hangs off the new turbo is such that the drain is slanting upward and the oil level is probably right up to the neck of the tank before it is able to drain out(severely reducing the capacity of this already much smaller tank)
3.) the amount of oil that goes through this turbo seems to be

As soon as I get a chance I am going to try a few things to see if this problem will finally go away:

1.) beat the drip tank untill it is at a more appropriate angle relative to the turbo (this will also help me get some frustration out)
2.) make a vent for the drip tank
3.) if the first two don't work, I am going to experiment with putting a larget BB in the check valve (10-10.5mm)
4.) if this stuff still doesn't work, I am going to put a drain on the other side of the drip tank going to the passenger side timing cover
5.) if all of this stuff still doesn't work, I am going to get an electric scavenge pump
6.) if this still doesn't solve the problem I am going to burn this thing to the ground and get a Corvette

I'll let you'll know how it goes...if anyone has any thoughts comments or solutions that have worked for them this would be a good place to put it.

- Jon
'86 930: 3.4 Andial build, Web GT2 Evo cams, Carrillo rods, ported/polished heads, MSD 6530, B&B headers/exh + intercooler, K27HF, 1 bar spring, Tial wastegate, Andial FE, Lindsey Fuchs. Back in black!!!
Past:997S cab; '88 930; '86 951; C5 Vette; 4th Gen Z28; 3rd Gen Trans Am GTA; '71 Z28
Old 10-08-2009, 07:22 PM
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