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Old 06-24-2008, 07:34 PM   #1
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Default Oil on/in cold side boost tubes

Why? Bad EGR? Bad gasket? What should I check?The car has less than 92K on the ticker.

I picked up this 5-spd '95 from a guy that did stuff to it. It's got a Flying Miata BEGI 4.2 turbo setup on it. Only boosts 8psi but it'll get more later. The guy gave me a MegasquirtV3 board and MSII CPU and some 550cc injectors.
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Old 06-24-2008, 10:29 PM   #2
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You have a couple possibilities. The engine might have large amounts of blow by if the crankcase breather is attached to the turbo intake tube thus the oil in the turbo and IC piping.
The turbo might be leaking oil due to age/wear or it might have a messed up drain or you could be over pressurizing the turbo, thus needing a restrictor. Is the turbo smoking?

How many miles on the turbo?

Is this the $3800 deal in atlanta?
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Old 06-24-2008, 10:37 PM   #3
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Crankcase pressure will also find it's way into the turbo via the drain tube.
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Old 06-24-2008, 10:38 PM   #4
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I have no idea how many miles on the turbo. Yep, it's the $3800 STEAL in Atlanta

Someone suggested moving the PCV to the low pressure side and capping off the barb on the high pressure side. I'll clean everything out, move that and then try it. There's no oil on the hot side (before the intercooler) so it's probably not the turbine itself.
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Old 06-24-2008, 10:41 PM   #5
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I was going to buy that car if you hadn't. Good buy.
Your PCV valve is probably bad as well. Test it and replace it. Or eliminate it entirely with a catch can with vacuum from the turbo intake helping it along.
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Old 06-24-2008, 10:45 PM   #6
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Where the hell is there room for a catch can in the engine bay? I don't know how to test a PCV other than shaking it and listening for the click. If I were to go the catch can route, do I just put that in the middle of the vac line with the tee pointing down into the catch can?
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Old 06-24-2008, 10:51 PM   #7
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Blow through the PCV, its a check valve, if it leaks boost into the crankcase your oil won't drain out of the turbo and it can be forced out of the compressor and turbine seal. I don't run a catchcan, just a PCV and a tube from the breather to just after my filter on the turbo intake. You want the inlet for the catch can to be at the bottom, the outlet should be at the top, the catchcan should be baffled with some kind of scrubby or something similar to catch the oil.

Do a search or PCV and another for catchcan. Reply back tomorrow, there is enough to read to keep you busy the rest of the night.
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Old 06-24-2008, 10:55 PM   #8
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Okay, so capping the barb on the high pressure pipe and rerouting the PCV to the turbo inlet is definitely an option.
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Old 06-24-2008, 11:06 PM   #9
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What do you mean by high pressure pipe?
The PCV valve is on the passenger side of the engine and it attaches directly to the intake manifold. The driverside has a port which most refer to as the crankcase breather. It is not a good idea to block this port nor the other one. You need both ports to move enough volume to alleviate positive pressure in the crankcase.
The best option, attach both ports in the valve cover to the lower portion of a catch can, then attach a vacuum line to the top of the catchcan to the intake tube pre-turbo.

WTF do you mean by high pressure pipe? Your PCV isn't attached to a charge pipe is it?
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Old 06-24-2008, 11:10 PM   #10
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No, it's attached to the pressurized intake manifold. I meant block the barb on the intake manifold and run another vac line from the PCV to the turbo intake piping.
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