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Old 06-21-2020, 01:25 PM   #1
Mbeas96
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Default Fudged up my turbo rebuild...

TL;DR - rebuilt 16t, upgraded to 19t wheel and cover, now blowing ton of oil out of turbo.

Not to long ago I was having an issue with burning oil, mostly idling (smokey exhaust) but also on decel after a hard pull. Removed the turbo and found some oil reminants in and around the exhaust housing. Not leaking oil from any seals, I figured it was time for a rebuild.

Bought a genuine Mitsubishi tdo4 rebuild kit for the superback turbo and a bigger compressor wheel and housing (19t upgrade). Took the CHRA to a local machine shop and he clearanced the compressor wheel lip 1mm all around. 56mm --> 58MM.

Brought everything out on my kitchen table...and watched step by step from ARD tuning on YT, how to rebuild it. Everything went exactly as planned. There is still some side to side play, not enough to hit the housing, and a smidge of in out play. Wheel spins freely and I was stoked.

Put it on, along with an angled housing and new downpipe. And within 500 miles, I've lost 2 quarts of oil, but this time it's blowing out of the compressor housing into the intake. Also LOTS of oil in the turbo inlet hose from the pcv box.

Hoping the drain was clogged or I forgot to put the restrictor in the feed, ripped it all apart to find nothing out of place. Drain completely clear and restrictor on the feed is there. I've cleaned the pcv system and ensured no blockages, added a catch can in the mix and hasn't changed the oil spewing in the slightest.

As of now, after putting it back together, again, I didn't changed some seals that I removed and now is leaking oil out of the engine as well. So not drivable at this point.

Besides leaking oil, what could've happened inside the turbo to make it launch oil like crazy? Is there a certain bevel or similar on the compressor side lip of the CHRA? Piston type rings on the shaft didn't seal and is just letting all the oil thru? My current thought it to pull and reseal the motor and put a stock 16t back on...

Screenshot_2020-06-21-13-17-09.jpg

Screenshot_2020-06-21-13-17-12.jpg

Screenshot_2020-06-21-13-17-25-1.jpg

Screenshot_2020-06-21-13-20-19-1.png
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Old 06-21-2020, 03:17 PM   #2
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So.... you put a 19T wheel on the existing impeller & didn't rebalance the assembly? They enlarged the recess groove in the CHRA for the compressor wheel, or reduced the compressor wheel? Not clear.

Also, when rebuilding a CHRA you need to completely de-coke the piston & oil ring grooves in the back of the impeller, and in the CHRA.

The inner & outer oil (metal) rings are what keeps the pressurized oil pushing through the bearings & thrust plate. If any of that wasn't perferomed properly, the replacement bearings, etc., are probably toast already.







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Old 06-21-2020, 03:26 PM   #3
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Why do you have an oil restrictor? This is not needed at all.
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Old 06-21-2020, 03:33 PM   #4
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If you look at the first? Pic, I'm not sure, tried to upload thru tb but doesn't look like there showing unless you click on it, you can see the 1mm edge around the inside of the chra compressor side machine larger, for the bigger wheel.

I cleaned the chra and turbine shaft and turbine wheel very well using commercial degreasers, an ultrasonic machine, and various picks and brushes.

Balancing....I've read different experiences all over the place. So I don't want to argue that fact, but I don't think it would make it lose oil? But just destroy itself by hitting the housing, no?

I replaced every component that came out of the turbo with genuine Mitsubishi parts. Following this video:https://youtu.be/8ndPYmfQuXU

So, obviously I messed something up, or really that's what I'm hoping. The machine shop definitely hadn't done this before and I had to tell him what I needed, which I'm hoping just clearancing the chra is all that was needed...

Restrictor; when I built this engine 2 years ago I purchased the kinugawa stainless steel coolant and oil flex lines. The oil inlet "port" that threads into the chra is restricted down to a pin hole the size of a toothpick, maybe a tad larger. I always thought that was necessary...but again, too little oil wouldn't cause it to blow oil I wouldn't think.
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Old 06-21-2020, 03:37 PM   #5
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Screenshot_2020-06-21-15-36-39.jpg
I wish I would've taken more pics...but here the shaft is before I cleaned it. Fresh out the 16t

I should note though, it is a beast. It boosts fast and strong. It was at 23psi holding steady and was fun as hell. Wayyyyy better than the 16t. Reminded me of the Mazda speed 3 I had for a very short amount of time.

Last edited by Mbeas96; 06-21-2020 at 03:43 PM..
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Old 06-21-2020, 03:52 PM   #6
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Either way my car is coming apart today, happy Father's day! I'll eventually take the turbo apart and see what all the fuss is about...for the meantime I'm sure it'll be easy to acquire a stock 15g 16t and put it on the angled hotside.

But first the fix the pesky oil leaks.
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Old 06-21-2020, 03:53 PM   #7
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You don't need a restrictor and this would screw your turbo up causing it to seize if it doesn't get enough oil. If you are changing to a large compressor wheel, it absolutely needs to be rebalanced. Whatever the case, rebuild it and send it out for rebalance and see how it goes. The rebuild cannot be screwed up. It only takes a few minutes to put together.
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Old 06-21-2020, 04:20 PM   #8
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Speaking from experience, balancing is overrated for these turbo's, which I think are component balanced and not assembly balanced. I rebuilt several TD04's with china rebuild kits and also swapped compressor wheels. Never had any problems.

Also from a financial point of view it makes zero sense to spend 100$ to balance a 50$ turbo, but opinions may differ.

Are you absolutely sure your turbo drain and crank case ventilation are OK?

Edit: I see you mentioning in and out play. I don't think there should be any perceptable play here! This is probably the cause of your problem. You installed a new thrust bearing? Did you use the correct torque spec on the nut?

Last edited by Sjeng; 06-21-2020 at 04:28 PM..
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Old 06-21-2020, 04:32 PM   #9
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Quote:
Originally Posted by Sjeng View Post
Speaking from experience, balancing is overrated for these turbo's, which I think are component balanced and not assembly balanced. I rebuilt several TD04's with china rebuild kits and also swapped compressor wheels. Never had any problems.


Are you absolutely sure your turbo drain and crank case ventilation are OK?
So, the drain is a stainless steel braided hose going into the yoshifab block fitting with a AN fitting. I made sure everything was clear, stuck a screwdriver thru the block fitting and took off the drain hose and I could run water without a blockage.

Crank case vent; so I've been considering (with the help of TB) that the rings might be shot causing blowby. First, I cleaned all the pcv hoses and the "y" connector coming from the oil separator box, took that box off and cleaned with gasoline and rinsed clean. Water was slightly discolored really, but no chunks came out. The drain back hose to the sump actually stuck to the pcv box as I removed it...so that was made sure it was still clear, and I even cut it shorter to aid in blockages in the future.

Turbo still shat oil, so I added in a "catch can" vented cap and pcv box went to the can, then the turbo inlet hose that would normally go to the pcv box I ran to the can for the main source of vacuum. The "y" by the box is still there with the intake manifold connected still there as well. Catch can has barely any oil in it. There's a lot in my intake.

Compression tested the other week. I have it in my build thread, I forget exacts, but on a cold engine the first 3 cylinders were around 155, number four was around 130ish, added oil to cylinder 4 and no change. So I *think* I ruled out rings, but possibly a blown headgasket? (Leaking oil from what looks like where the head meets blocks)
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Old 06-21-2020, 04:35 PM   #10
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Quote:
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Edit: I see you mentioning in and out play. I don't think there should be any perceptable play here! This is probably the cause of your problem. You installed a new thrust bearing? Did you use the correct torque spec on the nut?
Well darn, I was concerned at first inspection afterwards, but after some googling I was brought to believe it was normal...so I thought.

I believe it was 48 in/lbs or similar, but yep. Torqued to spec and red loctite. New thrust bear as well.
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Old 06-21-2020, 04:36 PM   #11
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That's strange, wonder why there still is axial play then. Just checked a used 13G here, definitely no axial play.
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Old 06-21-2020, 04:38 PM   #12
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Coz probably bearing housing is worn
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Old 06-21-2020, 04:48 PM   #13
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There's a superback and flatback version of the TD04 rebuild kit. I don't know if this could cause these issues?
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Old 06-21-2020, 05:03 PM   #14
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Regardless of opinion, balancing the assembly matters, especially when changing the compressor wheel to a larger size. I think Gpop was who I used to use - it's been some years now since I've dealt with any Mitsu turbos - this one they repaired the oil ring seat on the impeller - it was shouldered due to worn thrust plate



There is no way that it is (your turbo impeller/compressor wheel) in any sense balanced. Sure, you could swap similar wheels & probably get away with it. Since a genuine Mitsu turbo is NOT $50 to replace, personally I'd say it's worth the cost of balancing. I have rebuilt many a stock 15g /16T/19T without balancing, however that is when only seals, bearings & thrust assy are being replaced. I mark the shaft/nut/wheel & that has always worked for me.

There should be no axial play. Something didn't go together correctly, or the parts were mismatched.

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Old 06-21-2020, 05:49 PM   #15
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Ive used that same video when I rebuilt mine. There is a place that is unclear and caused me to put a thrust washer (not sure of the name) in backwards. Ill do little digging and get back with you. In the video it almost looks like they put it in wrong? Its just hard to see. So Id recommend to take it apart and use a different video. Or find a diagram to go by, very good info above. You dont need an oil restrictor that is for different type of setup.
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Old 06-21-2020, 05:56 PM   #16
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This is a clear diagram *(from Mitsu manual) of the assembled order - just ignore #7 since Mitsu for Volvo doesn't use the bearing snap ring setup

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Old 06-21-2020, 06:50 PM   #17
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It was a super back rebuild kit. But I'm now 100% certain that I did some thing wrong putting it back together. I'm always hesitant posting here, but every time, great info is shared. Thanks again for that!

Car is on ramps right now, I haven't dived in yet, but soon. I'll make sure to take note of the way everything came back apart and report back. I'd be very relieved to find that I installed a washer/bearing backwards, but like I said, everything felt like it went smoothly...
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Old 06-22-2020, 08:52 AM   #18
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Check wear of bearing housing sealing surface of shaft seal could be worn
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Old 06-22-2020, 10:18 AM   #19
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Ron's turbo shop in Utah will rebalance assembly for a reasonable price. None of this $75-100 non sense that a lot shops charge these days.
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Old 06-22-2020, 01:55 PM   #20
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Too much thrust play could certainly cause a compressor side leak.

I know I've said this before here but it's worth repeating: the piston rings are *gas* seals, as in air and exhaust gas. They prevent blow-by and leakage of boost and exhaust gas into the center housing. They are not, and cannot act as liquid oil seals. The difference in gas pressure across the piston ring is what keeps liquid oil from leaking out while running. When the engine is under load and in boost, there should always be positive pressure inward into the turbo's center housing, on both sides.

That being said if something as assembled incorrectly the axial clearance (in & out) between the piston ring, its groove, and other features like slinger grooves and deflector plates could allow more oil into the piston ring area, which can then get pulled across into the compressor when it's not in boost. Do you notice more leakage or smoking when engine braking, going downhill with trans in gear but foot off the accelerator, for instance?
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Old 06-22-2020, 02:43 PM   #21
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Too much thrust play could certainly cause a compressor side leak.

I know I've said this before here but it's worth repeating: the piston rings are *gas* seals, as in air and exhaust gas. They prevent blow-by and leakage of boost and exhaust gas into the center housing. They are not, and cannot act as liquid oil seals. The difference in gas pressure across the piston ring is what keeps liquid oil from leaking out while running. When the engine is under load and in boost, there should always be positive pressure inward into the turbo's center housing, on both sides.
?
Interesting. I always assumed they acted like oil rings on a piston. How does that explain oil not leaking when idling or heavy decel? There is no positive pressure on the compressor side then, or am I missing something?

Garrett (sample link) does talk about the pressure differential, however it also says this:

"At the turbine end, the sealing system is simple. After the oil has finished its work in the bearings, it travels along the shaft until it reaches the hub, where the spinning oil thrower literally throws the oil outwards by centrifugal force and it meets the inside face of the center housing where it drops down under gravity to be collected by the oil drain and returned to the engine sump. In addition to that, one or two piston rings are used which fit into a very accurately machined “stepped bore”. Unlike the piston rings inside the engine cylinders, these piston rings do not move. During the assembly process, the piston rings are compressed and once they are correctly located, the piston ring never changes position."

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Old 06-22-2020, 08:37 PM   #22
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the video that he used it looks like piece #8 goes the other way. I know cause I made a mistake once, but took it back apart before I installed it. I flipped it like it should and everything went together smoothly. Im just saying Id take it all apart and start over.
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Old 06-22-2020, 11:11 PM   #23
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I had an issue with a rebuild/compressor change out. The new compressor wheel assembled and torqued to spec, and it still had in/out play. Probably close to .2, maybe .4mm of play. Ran it and it immediately smoked. Removed it, disassembled and heated the compressor wheel for 10 minutes at 350f in the oven. Cleaned and froze the mostly assembled chra. Plopped the hot compressor over the frozen shaft, dropped the nut on and snugged to spec. Let it cool/normalize and checked the torque. No more in/out play at all.
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Old 06-24-2020, 03:35 PM   #24
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Originally Posted by lookforjoe View Post
Interesting. I always assumed they acted like oil rings on a piston. How does that explain oil not leaking when idling or heavy decel? There is no positive pressure on the compressor side then, or am I missing something?

Garrett (sample link) does talk about the pressure differential, however it also says this:

"At the turbine end, the sealing system is simple. After the oil has finished its work in the bearings, it travels along the shaft until it reaches the hub, where the spinning oil thrower literally throws the oil outwards by centrifugal force and it meets the inside face of the center housing where it drops down under gravity to be collected by the oil drain and returned to the engine sump. In addition to that, one or two piston rings are used which fit into a very accurately machined “stepped bore”. Unlike the piston rings inside the engine cylinders, these piston rings do not move. During the assembly process, the piston rings are compressed and once they are correctly located, the piston ring never changes position."
I hadn't seen that sealing article yet, looks like we got someone other than marketing people to write it! It's a pretty good explanation of what's going on.

The oil seal is not a single part but rather a system. It's a labyrinth type arrangement between the bearing and the piston ring, with the goal of blocking or slinging as much oil away as possible. The way to get oil to not leak past a piston ring is to not have oil reach the ring. Keep it away, and keep a positive inward gas pressure differential.

Unless we're talking a draw-through carb turbo setup, the compressor is never really in much of a vacuum. Even when the engine itself and intake manifold is not in boost, the compressor is upstream of the throttle body and will almost always be at or above atmospheric pressure. At high engine speed / low load conditions like off-throttle coasting or engine braking, there will be higher airflow without boost, and a depression across the air filter can cause pressure in the compressor housing to go below atmospheric.

The key is the pressure differential matters. The interior of the turbo's center housing is at crankcase pressure, or very near it. With PCV you have vacuum in the crankcase due to it being linked to the intake manifold vacuum at idle or decel. As long as the center housing gas pressure is below the compressor housing pressure, you have air acting inwards on the piston ring, keeping the ring seated and helping to keep oil away from the ring on the inside.

Double piston rings in turbos can be used on either compressor end or turbine end or both. Sometimes there's even 3 rings on bigger units. All in the name of reducing gas blow-by, not for reducing oil leakage. Important to make that distinction.
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Old 06-25-2020, 10:06 PM   #25
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Wow, there is certainly a lot more discussion on this thread than I anticipated. I've been busy with work lately, but I'm all for taking apart and reassembling. Thinking back, during the re assembly the compressor wheel was tight fitting on the shaft. I ended up freezing the turbine for a couple hours and then setting the wheel down. It did have some friction, maybe to much?

Duder, just to say, I always look forward to what you have to say regarding turbos and how they work. Way more info than I could ever find myself on google...its nice to know those "ring" type seals do not keep oil from passing, but that in/out travel of the turbine/compressor assembly could.

I am convinced that there is an issue with the rebuild. Whether it be the wheel not sitting down far enough because I did not heat the wheel, or maybe I did put the thrust washer or something backwards. Now the question is will I need a new rebuild kit? Could I clean, reassemble and have no in/out play? Or should I just bite the bullet and learn from my mistakes. The plan was to not have to touch the motor again, move on to brakes, suspension, etc... and now I'm buying dealer seals for the turbo side of the motor, so I really don't wanna have to pull it apart again.
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