dcg9381

Hey, blaast, got any ideas?

I bought this as a reman'd Garrett - .60/.63. I drove it between 100-200 miles on 10w-30 dino. If it doesn't look Garrett to you, let me know..
<10 psi, wastegate set at 7psi.
I suspected an oil problem, but I measured the idle oil pressure at the turbo at 20psi (idle) to 65psi (at RPM).

I believe the turbo was starting to get out of spec, so I wanted to tear it down before it did any expensive damage. I measured the lateral play in the compressor turbine (up / down) at .030 total, top to bottom, which is out of spec.

I expected to see oiling issues. To my eyes the bearings look good, I've got more wear on the hot side journal bearing than the compressor side, but neither one looks particularly out of spec. Both bearings appear to be standard size. There is a little more wear one the hot side of the turbine shaft than the compressor side, I dont know if this is normal. It's nothing I can feel with my fingers, but I can see it as bring spots on the shaft.

Thrust bearing looks fine.

The only thing that looks odd to me is the thrust spacer that sits in the back plate of the compressor. It sits loose in the back plate. Back plate doesn't show any signs of wear...

I'm kinda lost here as to why this guy was starting to fail.. Any ideas? Good news is there doesn't appear to be any housing/turbine contact, so this should be an inexpensive rebuild in terms of parts.

Full pictures at:

http://lakebox.dnsalias.com/photos/1.../turbo/turbo3/

dcg9381

Note, I may have been a bit over cautious with this one. I was measuring the axial play at the end of the turbine shaft (compressor side) with a caliper.
To correctly measure the limits of free play, I should have been using a dial guage going through the drain port and lifting/pressing both sides of the turbine while rotating.. finding maximum axial displacement... (if that makes any sense).

I think free play can get magnified at the compressor end, where it's away from the bearings... Any thoughts?

dcg9381

Axial play at the center of the turbo, measured at the shaft throught the oil drain is something like .012.
End play.. A good deal more, like .030, which is why I thought it was out of spec.. comments?

http://lakebox.dnsalias.com/photos/1...3/MOV06054.MPG

samson

I feel as if you are an advanced HMT'r that only certain members can actually provide any help. I see what you're saying about the way the journal bearing sits loose. Did the vehicle ever smoke? Oil noticably anywhere on/around the turbo? I want to keep these threads you make on top to get some serious help to this issue. Frustrating, especially with a freshly rebuilt turbo.


JP

dcg9381

Sampson, I appreciate it..

It's the thrust spacer that sits loose in the back plate. If it takes an axial load, maybe it should be that way? Dunno... I haven't seen this sort of seal setup before due to my inexperience.

If one of the vendors/rebuilders (like Blaast) care to comment, it'll be a big help.
You're right, this probably isn't junkyard turbo "just get a new one" discussion.
Turbo never smoked. No signs of oil. I'm very cautious with a new turbo as I've ruined a few already due to various issues like high EGTs (bad tuning), not filtering my oil supply, and using an inline filter that was too small. As you know, if you pull the turbo once it's had turbine on housing contact (even for a second) you're looking at a couple hundred for parts alone, not to mention the cost of balance.
It never showed any signs of doing anything odd other than buring off some coating (fumes) after 50 miles, I was just pulling the intake and checking the free play after driving it every so often. It got to a point where I was concerned with the amount of free play and didn't want to ruin another turbo.

Here's the mystery to me:
1) I've read that axial (up down) free play should be measured at the center section, turbine installed, via a dial gauge. I just so happen to have that tool and associated magnetic base. When I measured it last night, my axial free play at the center of the turbo was something like .013, well within spec. This is probably a very good test for bearing / shaft wear.




2) Other things I read say that you should check axial free play at the compressor end. If I do this, I'm at .030, which I think is too much play...

SDRAWKCAB

I have absolutely no idea but i wanted to comment just to find out the answer.

BLAAST

When a good turbo rebuilder takes apart a defective turbo, he should be able to tell what went wrong.
For that reason, I say: don't tear down a turbo unless you are equipped to fix it (takes more than a dial indicator)

THe shaft play is not the direct cause of the leakage.
the Wear of the piston rings is.
a 0.013 lateral shaft play is not enough to cause seal ring wear but the 0.030 end play definitely will (already has, obviously). it should be less than 0.003 in and out play so basically, none.
You can buy a EBay rebuild kit and do it yourself (people on here seem to think it's possible....) Or if you don'T want to Ruin it for good, send it to a profesional rebuilder and you'll be done with. Some turbo rebuilders warranty their job. be carefull with the shops mostly used to work on truck turbos. THey tend to use the same balancing criteria as for the large diesel turbos, which is not stringeant enough for a t3 or t3/t4. Be careful about other shops that will "Gpop" chinese parts at you to make sure you fail and that you come back to them for a bigger rebuild job.

dcg9381

Blaast, I think you mean that no one should ever take apart a turbo, as most of us don't have the equipment required to dynamically balance it, correct?

I find it valuable to take apart the turbo, especially if I think I'm,diagnosing and oiling issue. I've already had one major turbo rebuilder improperly incorrectly "diagnose" a turbo failure.
For the rebuild, if it's out of spec something is going to be required other than just bearings in most cases..

BLAAST

well actually it'S not just the balancing that requires profesional equipment and care. turbo shops have lots of specialized equipment to straigten, machine down and polish the shaft, overbore the center housing as well as the piston ring grooves. Even the wrenches to properly torque the nuts without bending the shaft are needed.