Why do I keep blowing turbos?

[Tachyon]

During the Spring Cruise, the seals in my 16g were compromised (at just 18psi) and the turbo started blowing smoke like a fog machine. This was unpleasant. Shortly there after, I replaced that unit with a freshly rebuilt 20G and life went on as usual. This turbo felt quite good with 0 shaft play and I decided to run it the rest of the summer on low boost (~22), lest it suffer the fate of my last one.

Fast Forward to last week. After using this turbo for the past 3 months, I started to notice a hint of smoke between shifts. Shit. Before too long I started hearing the all too familiar death whine from the unit followed with an ever increasing amount of oil burnt on vacuum. Last night I started taking it apart and noticed that there is about a 1/4 inch of shaft play and the compressor will touch the housing from time to time. Fun.

I am going to rebuild it before the cruise because 2 minutes of idling will turn the surrounding area into an opaque biohazard zone. I however, need to figure out why I've blown the seals on 2 otherwise good turbos in 1 year.

Here's what I know:

The turbo is fed with a SS line from the Oil Filter Housing. This oil is straight 30 weight changed quite regularly with a wix.

The car is always warmed up for a few minutes before operation, and completely warmed before boosting.

I do not run a turbo timer, but try to refrain from boosting a few miles before my destination.

The oil return line is stock, but appears to flow quite well, although I am uncertain if it's sufficient or not with the supply from the OFH.

The PCV valve does work well, although the system is stock and I am unsure if I should be running more crank evac.

The head is freshly decked and has new valve seals, this is mated to a decked 2.1 with A1's and a Permatorque.

There is no visible oil in the intake manifold or IC piping.

I do not employ a NLTS, Anti-lag, or launch control device.

The plugs look clean, and my AFR's and timing are where I want them on E85.

Anyway, that's what I know. If some of you more turbo savvy guys might have some ideas, regardless how brutal, I am all ears. I just want to learn what I am fucking up so I can waste less money then I usually do on this car. Thanks guys!

[Kracka]

Who rebuilds your turbos?

[Shane@DBPerformance]

Ever check the oil pressure on the line going to the turbo at different RPMs?

Air filter letting debris through?

BOV not good enough?

Ever have compressor surge?

[aaronspeed]

I have seen this when rebuilding units and it is to much oil pressure to the turbo.

[CarPsyco84]

Mitsu turbos should have oil fed from the head, like they were designed to be. Its probably too much oil pressure.

[Super Bleeder!!]

When you say straight 30W do you mean exactly that, or do you mean a multigrade like 10w-30?

[turbotalon1g]

My vote is too much oil pressure.

But a better answer to you. I think that oil might be too heavy (not sure?)
OFH is higher pressure than the head so that is why i voted too much oil psi, also do you have balance shafts? removing those correctly will increase oil psi esp at the OFH.

Return line: On what I though is a stock longblock had RTV inside of teh return line, it was solid but it would of provided some blockage, so I'm not sure if you have touched yours, but it might be something to check and for the couple of $$ for a new gasket could be worth it while you are changing/rebuilding turbos.

I'd say change to a head feed or find a way to measure oil psi at the OFH at minimum but preferably the turbo, I bought some fittings to allow me to do this at the turbo to test with my holset, but I never needed it/got round to it.

Good luck. I hope you get this figured out.

[twack]

Who rebuilds your turbos?
100% this was exactly what i thought.

people quit having your turbos rebuilt, it nothing but headaches in the long run. turbos are relatively cheap compared to 5 or 10 years ago just get a new one and have it last for year and years

[Goat Blower]

I think that's it too. You can't just rebuild turbos in your garage and expect them to last. They spin at 100,000 rpm, so any little imbalance is going to be a big deal, that's why real turbo builders use a VSR or similar balancer.

[Tachyon]

Thanks for your responses gentlemen. Thinking back now, I've owned the car 7 years, but this year was the first year I've had turbo problems -and- ran oil from the OFH.

Also my balance shafts are removed. I don't have a numeric pressure gauge, but for what it's worth, the oil pressure at the stock sender is at the 2nd hash mark (the one on the right) when I'm on it.

Super Bleeder, it's a straight 30 non-detergent SJ variety (similar to Rotella Diesel)

Shane, I've got a crushed 1g BOV. When I am in a high load, low boost situation and let off the throttle before building more than a few PSI, I have a noise similar to compressor surge, but I am not sure if it is surge or BOV flutter. I am kinda inexperienced in that area to be honest.

Steve, I honestly do no know who rebuild the last two, I purchased them from local Mitsustyle members because I needed to hit certain deadlines. I am not opposed to buying a new turbo, but I need to make sure I do not wreck the next one too.

I'll be getting a new turbo over the off season, but for now, seeing I am the only DSM signed up for the Fall cruise (FFS people...) I am not sure I can get a new turbo in that quickly...