Turbo Assessment

DOC4444 · **Posted:** Sun Mar 31, 2013 10:50 pm

I have our Jeep apart to do the TB, etc. To my fingers, the turbo shaft has no perceptable endplay and the slightest bit of axial play. (Any less and I do not think I could feel any.) One vane has two tiny nicks on the edge of that vane, 1/8" apart near the outboard end. They are just deep enough to catch a fingrnail in. So, it ingested something at some point, but the shaft seems to spin pretty freely with my fingers. However, I have no previous experience with handling turbos.

Can anyone comment on what you think? It has 115K on it and has been run with EGR disabled (initially SEGR and since 60K, GDE tunes with SEGR disabled) and EHM for the last 85K miles. Mostly Mobil 1 0W-40 has been used with 5W-40 in the summer. 5K oil change intervals where it takes at least 4K before the oil gets at all dark.

MAF test yielded 19.4 at sea level so I assume the rockers are in good shape.

Thanks in advance for your thoughts...........

DOC

LMWatBullRun · **Posted:** Mon Apr 01, 2013 10:36 am

DOC4444 wrote:

I have our Jeep apart to do the TB, etc. To my fingers, the turbo shaft has no perceptable endplay and the slightest bit of axial play. (Any less and I do not think I could feel any.) One vane has two tiny nicks on the edge of that vane, 1/8" apart near the outboard end. They are just deep enough to catch a fingrnail in. So, it ingested something at some point, but the shaft seems to spin pretty freely with my fingers. However, I have no previous experience with handling turbos. Can anyone comment on what you think? It has 115K on it and has been run with EGR disabled (initially SEGR and since 60K, GDE tunes with SEGR disabled) and EHM for the last 85K miles. Mostly Mobil 1 0W-40 has been used with 5W-40 in the summer. 5K oil change intervals where it takes at least 4K before the oil gets at all dark. MAF test yielded 19.4 at sea level so I assume the rockers are in good shape.

Thanks in advance for your thoughts...........

DOC

No play is good. My SOP from here out is to check the endplay by removing the intake hose at every oil change. As long as the play is low, it should be fine. Once I start to see perceptible wear, then I will change it.

dirtmover · **Posted:** Mon Apr 01, 2013 11:15 am

DOC4444 wrote:

One vane has two tiny nicks on the edge of that vane, 1/8" apart near the outboard end. They are just deep enough to catch a fingrnail in.

Grinding marks from balancing?

DOC4444 · **Posted:** Mon Apr 01, 2013 11:58 pm

Good thought, but no, the metal is raised around each nick just as if you made them with a sharp chisel. Definitely not ground. Am leaving them as is so as to not affect the balance.

DOC

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The turbo balancing at Garrett is completed by grinding the center mass on the compressor impeller. No balancing is completed on the blades or blade tips as these are critical dimensions.

Hexus · **Posted:** Tue Apr 02, 2013 10:51 am

dirtmover wrote:

DOC4444 wrote:

One vane has two tiny nicks on the edge of that vane, 1/8" apart near the outboard end. They are just deep enough to catch a fingrnail in.

Grinding marks from balancing?

And probably shaped like this:

Turbo Assessment

Who is online