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m6smitten

WTF bearing fretting

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Pulled turbocharger apart and found this.

Comp Turbo rebuilt this unit 2 years ago and maybe has 400 miles on it.

Thoughts? 

16485E62-54CC-404D-B064-FC9AD7697D5E.jpeg

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I don't know if those are technically correct, though they may be the right size.

 

My replacement bushings were aluminum from an official KKK rebuild kit.

 

On the left of the image.

PC024441.JPG

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The fretted bearings are Aluminum. Comp Turbo wants to go brass next. They said there was evidence of some heat but it doesn't look like oil starvation to my uneducated eye. More like wobble.

Any chance you could put a micrometer on yours for verification? 

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I used them in my rebuild, but will look to see if I have the old ones.

 

My rebuilder told me at the time he could get the correct parts, but I never followed up.

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Attached is the invoice from when I bought the kit and the part number, though I think they are NLA, that was in 1985.

 

Pictures are at full resolution so you can see that there is no scoring, The brown is just tainting from the exhaust side. Nearest I can tell, they have 30-40K miles, with LOTS of track use, but with letting the Turbo cool down before shutting off the engine. Mobile 1 20W-50.

 

OD: 20 mm

ID: ~13mm

L: 14mm

img554.pdf

PC274544.JPG

PC274545.JPG

PC274546.JPG

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14 minutes ago, Yale said:

Comp turbo strikes again.

 

Explain this post please.

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Well I sent them parts of a turbo because Justin at Comp Turbo said they could make the rest in the same spec as the original. What I got back had very little to do with the original unit and I basically had to throw their work out. Not only that, that packed what they sent me so poorly that mounting pieces broke off. It was yet another pointless excercise in my turbo oddessy.

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Hey Men, 

I am still chasing the cause of the fretting in my turbo bearings. However, I just did the first oil change on the rebuilt motor and found the oil reeking of fuel. Thinking perhaps oil dilution caused by; leaking injector; fuel pressure too high; or blow-by.  Did i miss anything?

Hard to imagine the above because when tuning after the rebuild, the wideband only read slightly rich - nothing crazy. And the motor ran very smooth. 

Eager to hear your thoughts.

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If you are getting fuel in the oil check the injection pump.  If it is leaking internally you can get fuel into the oil there. 

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Good call. Is there a place on the pump I can verify? Or do I just pull the pump and have it tested?

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1 hour ago, m6smitten said:

Thinking perhaps oil dilution caused by; leaking injector; fuel pressure too high; or blow-by

 

Or leaking or malfunctioning cold start injector. Either way you would have to have really poor rings.....Simple check to look at / smell the plugs.

 

OR you may be getting fuel past the injection pump pistons as they may (as so many do) have micro cracks in them allowing the high pressure to push fuel past into the pump body then into the oil stream.

 

Many rebuilders may tell you those are NLA, which they are, but Precision has a way to repair them.

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Are you still using Comp Turbo and into another set of bearings?

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(edited)

OK, Ill check plugs and then compression for rings too if necassary. Thx. 

Comp rebuilt two turbos for me - one that I run and the original unit. They are re-rebuilding my runner right now and was going to install my original unit but I dont want to run the engine until I figure this fuel problem first. 

Edited by m6smitten

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