Turbo rebuild - bearing races scored?

[OM617YOTA]

Finally getting around to doing a turbo rebuild. To minimize vehicle down time, I'm rebuilding the turbo off my spare engine, and will then swap turbos on the truck when complete. I'm using the kit and manual from that source for Mercedes parts.

The manual states that if the bearing races are scored, the center housing must be replaced. One side of mine is lightly scored, only in a small section, not even half a rotation. This is the bearing race, not the bronze bushing. I can see the scoring, but I can't feel it with my finger tips. I can't get my fingernail on it but if I stick a plastic WD40 or carb cleaner straw down there, I can feel it with the straw but it doesn't catch. 98% sure it would be fine, but would hate to do all this work just to blow it up in the end for something stupid like this. I didn't think to get pics last night, I'll do so and post them ASAP, as obviously this is kind of dumb to ask without pics.

I searched but couldn't find anything on this forum, or on the internet in general. Does anyone have pics of scoring that is definitely bad, or pics of bearing races that are scored but still fine that I could compare to?

Worst case scenario, does anyone have a known good Garret center housing for a 617 they'd sell me?

[Mark123]

Did you know there are three 617 turbos in the Pick-n-Pull yards around Portland now? Two wagons and an SD. I don't know if they are Garrett

[Diesel911]

Originally Posted by OM617YOTA

Finally getting around to doing a turbo rebuild. To minimize vehicle down time, I'm rebuilding the turbo off my spare engine, and will then swap turbos on the truck when complete. I'm using the kit and manual from that source for Mercedes parts.

The manual states that if the bearing races are scored, the center housing must be replaced. One side of mine is lightly scored, only in a small section, not even half a rotation. This is the bearing race, not the bronze bushing. I can see the scoring, but I can't feel it with my finger tips. I can't get my fingernail on it but if I stick a plastic WD40 or carb cleaner straw down there, I can feel it with the straw but it doesn't catch. 98% sure it would be fine, but would hate to do all this work just to blow it up in the end for something stupid like this. I didn't think to get pics last night, I'll do so and post them ASAP, as obviously this is kind of dumb to ask without pics.

I searched but couldn't find anything on this forum, or on the internet in general. Does anyone have pics of scoring that is definitely bad, or pics of bearing races that are scored but still fine that I could compare to?

Worst case scenario, does anyone have a known good Garret center housing for a 617 they'd sell me?

I would like to know what Manual you are using. If it is a good one post the torque of the Shaft Nut please.

There is bearing bores in the Bearing Housing and there is bearing journals on the Turbine Shaft and there is a bore that the Seal rids in on the Aluminum Plate that is on the Compressor side.

Note that some are not going to like my resonse.
I worked in a shop were rebuilt Garret (Air Research), Schwitzer and Cummings Turbochargers. Concerning Turbos with the free floating bearings like the Garret ones and the bearing bores if there was marks that went around the bore we would use 500 crocus cloth (that is what the called it) and clean up the bore. If there was a small scratch around the bore and no metal was raised above the bore we reused it.

If it was really bad we sent the housing out and had them hone it out for an oversized outside diameter bearing.

It would be better to see a picture. Note what you cannot have is any scratching across the bore. That will destroy a bearing.

[OM617YOTA]

Thanks Mark, I didn't know that. This is the spare turbo off my spare engine, I still have the original turbo on the engine right now that I could take off and take apart if needed. Hitting junk yards around Portland would be hugely impractical right now.

Photos attached.

[OM617YOTA]

Originally Posted by Diesel911

I would like to know what Manual you are using. If it is a good one post the torque of the Shaft Nut please.

There is bearing bores in the Bearing Housing and there is bearing journals on the Turbine Shaft and there is a bore that the Seal rids in on the Aluminum Plate that is on the Compressor side.

Note that some are not going to like my resonse.
I worked in a shop were rebuilt Garret (Air Research), Schwitzer and Cummings Turbochargers. Concerning Turbos with the free floating bearings like the Garret ones and the bearing bores if there was marks that went around the bore we would use 500 crocus cloth (that is what the called it) and clean up the bore. If there was a small scratch around the bore and no metal was raised above the bore we reused it.

If it was really bad we sent the housing out and had them hone it out for an oversized outside diameter bearing.

It would be better to see a picture. Note what you cannot have is any scratching across the bore. That will destroy a bearing.

Thank you, this is exactly the kind of info I was looking for. Sounds like I'm good to go.

[Diesel911]

Well the picture tells a different story. It has more and deeper scoring then your word description would lead someone to believe. (Some rather large crap has gone through that turbo.)
That makes it more marginal then my previous opinion. If I was in a shop I would be measuring the inside diameter of the bore to see how close it is to the stock size and if it is elongated.

If the new bearings are bronze (they used to make aluminum ones) it is not going to cause any catastrophic failure; but you won't get the most extensive life out of it.

What did the shaft look like?

Note be sure the piston ring grooves on the Turbine Shaft are not worn out.

[OM617YOTA]

The pics look bad, but it's not any worse than what I described.

Shaft looks fine, and the bushings themselves have less damage than the turbo housing.

I'll also be replacing all the rotating pieces, new ones came with the kit. New shaft, new turbine, new impeller.

Thanks for taking a look.

[OM617YOTA]

Took it to a pro turbo shop nearby, they're going to hone the bore to clear up the scoring and sell me oversized bearings to match.

Wish I'd have known that place existed before I bought the parts kit.

[OM617YOTA]

Got the turbo center housing back, in good shape, with oversize bearings.

Turbo guy said he doesn't use Jrone components, but out of what comes from China, these aren't bad.

Painted the center section with high heat paint last night. Just need to head out to the shop and get it put back together. Too hot, that's going to wait.

[OM617YOTA]

Got the turbo back together, went quite smoothly. Waiting for a "convenient" time to pull the existing turbo off the truck and swap this one in.