4AGE turbo fail

[Vertigo]

Hey guys. This weekend I decided to put my turbo on, without it plumbed into the intake. Taking the oil feed from the oil pressure sender with a brass T piece, and despite it being a water cooled turbo, I wasnt going to initially plumb the water lines in because they require some cutting of vital hoses. Everything went pretty smoothly. I cranked the car over and observed a good amount of oil spilling out of the drain port of the turbo, then made up an AN line to route the spent oil to the sump. One thing I noticed immediately was that the outlet of the 90 degree AN fitting and the bung I had welded high in the sump were pretty much level. I had to kind of snake the line around parallel to ground level to get it all connected. I know its not ideal, but the turbo hangs low due to the manifold.

Started it up, and everything was fine, though it was a bit smokey. Went for a short test drive, and yea, smokey as $&#$%. Gave it some rev, and it made turbo wooshy noises. Cool. Came back in, tightened some of the fitting to address some minor oil leaks, went for another drive to get some stuff from Repco. Still smokey, and on the way back, thought I heard some odd noises, but thought I was imagining things.

Today, took the car to work, hoping that the seals might tighten up and itd stop smoking. The noise from yesterday got more noticeable. Got to work, immediately checked the shaft for play, and yep, it has some side to side play now. Looks like the sound I heard might be either of the turbo wheels contacting the housing. Ill be taking stuff off tonight to check out the damage - luckily its just a cheapo turbo, but it was brand new, so thats annoying. Dont mind replacing it and/or the manifold. Also lucky that the turbo wasnt feeding the engine, in case metal from the compressor housing was shaved off. But Im really hoping there arent metal shavings from the journal bearing now in my oil.

Any suggestions for what went wrong?

The oil drain line obviously needs to change. One thing I noticed was that oil kept spilling out of the line if I disconnected it from the turbo and lowered it, so the bung must be below the level of oil in the sump, at least when sitting, meaning the entire drain line is full of oil. The bung is pretty high up, so perhaps the sump is overfilled. Heres a pic from below.



So, few lessons learned here, especially with spinny things that require oil. 1) Water would probably have been ideal. 2) Proper oil drain is absolutely vital.

Couple of questions.
1) What kind of oil flow should a journal bearing turbo have? This is a pretty small turbo, but I gather that these bearings require a lot of oil pressure to make the shaft float.
2) How exactly does a restricted drain line cause problems? I would have thought more pressure at the bearing would be a good thing.
3) Could I clock the center housing like 20 degrees without issues, in order to gain a little more vertical drop for the drain line?
4) I plan to source my water from the side of the block, and return to one of pre-pump coolant hoses. Where in particular should I be looking?

[Vertigo]

Just as an indicator, theres not nearly as much play as in this video: https://www.youtube.com/watch?v=AekW0nEK5Gg

[thegreatestben]

I highly doubt your lack of cooling lines would be at play here.
I will let more experienced people comment on your oil supply issue, but you might want to give detail of the turbo as I'm sure there's specifics for different types when it comes to oil supply.

If I did have to wager a thought you've probably got your proportions of supply vs. drain all up the shit. You might have blown the oil seals out if you had too much oil trying to get in without the required volume of drainage.

[Vertigo]

Youre right, I should have noted some specifics. Its a T3 flange turbo, DPR branded. Not entirely sure of the AR's etc, its kind of an el cheapo special.

[sergei]

It is a bit hard to tell from the photo: instead of straight + 90 degree fitting, perhaps you can get two 45 degree fittings and fit much shorter drain hose?
If you turbo was not feeding the engine, it was possibly over-spinning if you drove under moderate load (if you have to temporary bypass turbo, maybe jam the waste gate open?).

IMHO it is not a good idea to have turbo free spinning. Simplest solution is to have following:
1) wastegate jammed open (as above)
2) turbo short-circuited (feeding itself). This prevents random crap getting in, and adding some load.

[RS13]

More oil pressure isn't better especially if the lack of drain is causing a restriction in flow out of the turbo, this would explain the smoke as the oil has nowhere to go but past the seals. You may need an oil restrictor in the feed if drainage is going to be an issue, or redesign your drain system for maximum flow.

Don't drive it without an intake connected as Sergei says, the compressor needs to be loaded up in order to create boost.. take away that load, the compressor will attempt to create boost against Earth's atmosphere (lol), meaning massive overspeeding which will end your turbo real quick.

Best thing to do would be to show your setup to a turbo shop, ask them for the best drain design for your application.

[whynot]

From experience with my build I also ended up with the turbo sitting extremely low. As in about 5mm above the oil level in the sump. I never had any problems with oil return and when I disconnect the return I get some oil coming from the sump unless it's jacked right up on stands. Definitely not an ideal situation but I managed to get away with it.

Someone else might be able to confirm this but I thought having back pressure on the drain would lead to oil leaking through the turbo seals not destruction of the journals or bearings in such a short time.

[Vertigo]

Took the turbo off last night and took it apart. Pics here. Point out anything you think is dodgy.

http://imgur.com/a/JDMuA

...turbo sitting extremely low...never had any problems with oil return...I get some oil coming from the sump...managed to get away with it...

Good info, thank you very much! Even so, Im leaning towards the idea of a log manifold now to mount it much higher - I want that vertical drop so I dont need to worry about it.

Someone else might be able to confirm this but I thought having back pressure on the drain would lead to oil leaking through the turbo seals not destruction of the journals or bearings in such a short time.

This could explain some of it. My engine does have a bit of blowby, and therefore crankcase pressure. Ive got the cam cover venting to a catch can, and then to atmosphere, so I thought I had solved this.

[jondee86]

Cut and pasted to save time

The seals in almost all turbos today are piston ring seals. They look like piston rings that
are compressed when they are installed to leave minimal gap between the ends of the rings and
around the rings. This forms a torturous path for the oil to prevent leakage into the air passage.
Most performance turbos use only a single piston ring on the compressor and turbine sides because
they do drag the rotation of the turbo which reduces mechanical efficiency. In applications sensitive
to oil leakage for emissions, etc. it is not uncommon for 2 piston rings to be used on both the
compressor and turbine sides.

On the compressor side, generally there is some kind of oil splitter which throws oil away from
the seal as it is spinning. Because the piston rings and the splitter are dynamic seals, when the
turbo is spinning faster, the better the seal operates.

The oil leak is driven by pressure, like any other fluid flow. When the oil pressure inside the center
housing of the turbo is higher than the air pressure outside of the seal, the oil wants to travel outside
to the air passage. The air that is holding the oil back on the compressor side is the compressor
outlet pressure and for the turbine side, it is the turbine inlet pressure. That is because it is the
air pressure that is behind the wheel (depends on wheel geometry and air pumping by the wheel too).
This is why turbos leak more at idle/low load conditions and leak less when under full load/boost.

Cheers... jondee86

[edwagon]

FWIW, I have had two different turbos on two different cars smoke due to oil drain issues.

The first one was poor drain design and came right with a re-route of the drain.

The second one was that the sump was overfilled - not by much, but by enough as it turned out - and was using the factory drain location in the block

I have also restricted the oil feed on turbos before due to smoking issues - specifically with using HT18s (ex 13b) turbos on piston engines - on advice from a turbo expert - but you'd want to be pretty careful about drying up a turbo unless you were sure you knew what you were doing.

[mike simmonds]

I had a turbo mounted too low once on a 4agze and it smoked the whole town out. Made a log manifold with the turbo high enough to drain properly and problem was solved. if you restrict the oil return it has nowhere to go apart from past the seals. I have run turbos without water plumbed in and makes no difference although might help the lifespan of the turbo.

[Vertigo]

Thats good to know. I now have a new turbo with new much higher flanged manifold. Should be ideal.

[RS13]

Thats good to know. I now have a new turbo with new much higher flanged manifold. Should be ideal.

Nice.

[mega4a]

i had similar issue with nissan turbos a 0.8mm restrictor was all i needed in the oil feed to fix the problem.

[Vertigo]

Were they ball bearing though? AFAIK, journal bearing turbos all have narrow passages that regulate the oil flow inside the core.

[mega4a]

the first turbo i had was off a nissan skyline r b20det/rb25det factory turbo which im pretty sure is journal bearing type and i used restrictor same thing happened would drive it and would be so smokey might have been a blowen turbo ? but the restrictor fixed the problem. but the the other turbos i have used were ball bearing t28 gtr turbo, and the gt2871r and i always ran restrictors with them my turbo drain always had a 45 degree fitting off the turbos too

from my experience i would run a restrictor the oil pressure is pretty high which is going to the pressure switch.

[Vertigo]

Rather than start a new thread for this, Ill just ask the question here.

The new turbo is a twin scroll TD05HR-16G-10.5... it is mated to a custom made 4AGE manifold, but Ive discovered that the compressor housing fouls on the AW11 clutch lines and mechanism. Evidently, this setup was used in a FWD configuration, so didnt have this problem.

Does anyone know if the TD05 exists in twin scroll and non-reversed config? Ie. so that the compressor housing sits on the opposite side of the turbo when mounted.

[whynot]

You could well be out of luck there. I didn't see any twin scroll non reversed unit when I was looking for my turbo. There wasn't a factory option anyway.

I settled on a tdo5 '20g' from kinugawa in the end. It's still a td05 and bolts in as factory but has the biggest compressor possible crammed in it and has a few compressor and turbine wheel options as well as some porting work over a stock unit.

Could an e56 clutch setup help with the fouling? Might have different arrangement to the aw11 gear.

[Vertigo]

Thanks for that, disappointing news. I dont think I want to go modifying the clutch system in the car, thats a bit out of scope of the original goal of the project and could potentially bring problems I dont currently have. Dont fix what aint broke!

One option I am considering is to stack a few 16v exhaust flanges to offset the turbo from the head about 2-3cm, hopefully enough to clear the clutch stuff but not touch the firewall, using some longer bolts. Any forseeable problems with this? I think Ill make up a support strut if I were to go this route, its probably a good idea for a turbo anyway.

[Vertigo]

As an aside, I think the original turbo is actually still ok - the slight play I found was probably just normal wear. Probably. The new turbo has pretty much equivalent play, and Ive been told its fine. So the only real issue was the poor oil drain making things smoke like $&#$%. If necessary, as a last resort, will go back to the old setup and think of a way to improve the drain.

In either case, the crankcase pressure must be resolved properly.