4.6l turbod 99 gt blue smoke

hawaiimuscle

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Jun 25, 2019
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So I’ve had this car for about a month now, it’s a 4.6l 99 GT, w/ 7675 turbo, Manley rods/pistons, egr delete, and comp cam cams and valve cover breathers on it.

When I first got the car it would smoke from the turbo/ exhaust pretty badly. It also needed an oil change very desperately. I did the oil change using 5w-30 and the turbo stoped smoking, but the exhaust keeps smoking and whenever the oil levels get low I’m pretty much driving with a smoke screen. The exhaust is coming out the front bumper and the other day I revved it up in neutral and literally sprayed the fire hydrant next to me with oil. I’m thinking worn piston rings? I didn’t see any oil in the coolant but the coolant levels have dropped a bit, maybe head gasket?
Any ideas what the problem is?
 
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Hoytster

I don't dare do that to my Knob
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Couple questions:

-What do you mean it stopped smoking from the turbo but is still smoking from the exhaust? Where was it smoking from the turbo originally?
-What brand and type of turbo is it (ball bearing, journal bearing)?

My initial thought is you are leaking oil past the turbo seals into the exhaust. Did you pull the plugs yet to see if they look oily? With the amount of oil it seems that you are losing, I would expect to see some serious carbon/oil buildup on the plugs if the engine is leaking internally. If the plugs look good, I'd move to the turbo itself.
 
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hawaiimuscle

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Thanks for the replies guys, will check out the plugs later today. I’m hoping it’s nothing internal.

I forgot to mention I’m running zero boost on it if that makes any difference (still needs to be tuned) Turbo is 7675 ball bearing precision turbo. Oil return line looks a decent size, definitely bigger than the feed line but it’s not an exact straight shot to the oil pan, so that could be it.
I’ll look at the spark plugs to verify it’s nothing internal and try to make the return line more straight forward. I’ll report back what happens.

Also, if it is the turbo backing up would that mean I need to replace the seals?
 

Hoytster

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Thanks for the replies guys, will check out the plugs later today. I’m hoping it’s nothing internal.

I forgot to mention I’m running zero boost on it if that makes any difference (still needs to be tuned) Turbo is 7675 ball bearing precision turbo. Oil return line looks a decent size, definitely bigger than the feed line but it’s not an exact straight shot to the oil pan, so that could be it.
I’ll look at the spark plugs to verify it’s nothing internal and try to make the return line more straight forward. I’ll report back what happens.

Also, if it is the turbo backing up would that mean I need to replace the seals?
Let us know how the plugs look when you pull them, but I'm betting they're going to look fine.

Nice turbo btw, you can make some really good power with that Precision! I was looking to run that on my coyote project but will probably have to upgrade to the PT8385. The precision ball bearing turbos are supposed to be internally restricted for the oil flow from the feed line, but I have heard many times from modular guys that they had to restrict the feed line down even more to prevent smoking. If oil is just leaking past the seals due to too much oil then you shouldn't have to replace the seals, only if they are damaged or worn should you have to replace them.

Precision has a good document on turbo installation guidelines that I would read through if you find the engine itself is in good condition. It goes over oil restriction and return line sizing, location, ect.
 

hawaiimuscle

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Had a terrible weekend gentlemen.. alternator took a dump on me, turbo oil feed line somehow came off the filter and literally pumped all the oil out whilst on the road, luckily I was just about to pull into the parking lot, so I didn’t run it very long like that. Lastly, I checked one of the spark plugs and they do not look good!
0B91BC11-F61D-4586-A881-CA99A6BC72FB.jpeg
 

Hoytster

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Sorry to hear about your weekend. I know how that goes as I usually have the same kind of luck!

Did the electrode end of that spark plug feel greasy at all? From the pic, it looks like that is just some carbon buildup from running rich and/or slight oil intrusion into the cylinder. From the amount of oil you described coming out of the exhaust, I would expect those plugs to be caked in oil if it was coming from the cylinder. I'd pull the remaining plugs and see if they are consistent.

Another way to check would be to pull the turbo and check the inside condition of the header pipes compared to the downpipe. That would be a good opportunity to see if you have a restrictor on the feed line and the condition of the drain line. I'm still leaning toward a turbo seal issue....