s16g turbo shaft worn.. reusable?

[90 TSI FWD]

Hey guys, I recently took out my small 16g because my car blew blue smoke when I boosted. I took it apart to change the seals/bearings and send the parts (shaft, wheel, nut, in/out thrust collars) to FP for balancing, yet I noticed that the bearings had worn into the shaft itself. The wear isn't deep at all, but noticable when you slide your finger across the shaft. Can I reuse this shaft? I personally think it should be okay. I'm thinking that when I put everything back together, I'll just have a small amount of side to side play, but other than that, the bearings and seals will be new, which is my main concern

What are your opinions on this?

Thanks

 

[fwdeclipse]

I had the same thing with my 20g and it turned out to not be ok. I had to get a new wheel. PM jsmux he is great to work with and can help you out quit a bit.

 

[JusMX141]

^^ He's right. I got him a NEW TD05H turbine AND had it clipped 15* for a 20G for about $50 less than what FP wanted for just a new unclipped turbine.

 

[JusMX141]

Hey guys, I recently took out my small 16g because my car blew blue smoke when I boosted. I took it apart to change the seals/bearings and send the parts (shaft, wheel, nut, in/out thrust collars) to FP for balancing, yet I noticed that the bearings had worn into the shaft itself.

Unless either of the wheels were damaged from hitting either of the housings, you're throwing money away by having it rebalanced.

The grooved turbine shaft isn't much of a concern as long as the grooves don't exceed .002" or so by measurement. The oil may fill that much of a groove as it's passing through the bearings.

In the case of fwdeclipse's turbo, it was grooved .004" on the cold side journal, and .006" on the hot side....but what made it unuseable was the fact that the grooves were only on one side of the turbine shaft- NOT the whole circumference. Had it been rebuilt and reassembled, it would've caused the rotating assembly to vibrate, possibly damaging the new compressor wheel and rebuild kit that he had just purchased. For the cost of the new turbine, it was worth it.

 

[90 TSI FWD]

Unless either of the wheels were damaged from hitting either of the housings, you're throwing money away by having it rebalanced.

The grooved turbine shaft isn't much of a concern as long as the grooves don't exceed .002" or so by measurement. The oil may fill that much of a groove as it's passing through the bearings.

In the case of fwdeclipse's turbo, it was grooved .004" on the cold side journal, and .006" on the hot side....but what made it unuseable was the fact that the grooves were only on one side of the turbine shaft- NOT the whole circumference. Had it been rebuilt and reassembled, it would've caused the rotating assembly to vibrate, possibly damaging the new compressor wheel and rebuild kit that he had just purchased. For the cost of the new turbine, it was worth it.

Neither of the wheels hit the housings. I talked to FP and they said "depending on how deep it wore into the shaft, we could regrind the shaft and use oversized bearings." I sent it to them because he had to see it himself.

From what I recall, don't the 14b turbos have the same shaft? If my shaft is too worn, may I use a 14b shaft instead?

Thanks,
Chad

 

[JusMX141]

All TD05H turbos use the same turbine. You could, in fact, use a 14B turbine.

 

[90 TSI FWD]

All TD05H turbos use the same turbine. You could, in fact, use a 14B turbine.

If my 16g shaft turns out unreusable, I will take apart a 14b and use that shaft then.

Thanks for the help

-Chad

 

[Mr Peepers]

If you use a turbine and shaft from a 14b and a compressor wheel from a 16g, IIRC you will want to get it rebalanced.

 

[90 TSI FWD]

If you use a turbine and shaft from a 14b and a compressor wheel from a 16g, IIRC you will want to get it rebalanced.

But of course! Balancing by FP FTW! Bytheway, what's IIRC?

 

[JusMX141]

If you use a turbine and shaft from a 14b and a compressor wheel from a 16g, IIRC you will want to get it rebalanced.

Mitsu turbos are component-balanced, meaning each part is balanced individually prior to installation. What that means is that if he were to find a perfect undamaged TD05H turbine from a 14B, it could rightfully be assembled to any compressor wheel in any TD05H turbo without worrying about the clocking of the compressor wheel on the turbine. I've been building turbos using this theory for years- including those on my own cars and my close DSMies' cars- and haven't had a single issue regarding premature failure due to balance to date. Maybe I've been lucky- but you don't get lucky a few hundred times in a row.

Think of it as balancing a car tire perfectly, and balancing the wheel perfect as well....then rebalancing the whole assembly once you put the tire on the wheel. If both components were balanced before they were assembled, there's no need for the last step.

I've come to find that the only turbos that absolutely require the complete rotating assembly to be balanced are ball-bearing units; which is why Garrett and other companies only sell complete CHRA's for these turbos. Balancing is so crucial to ball-bearing units that they don't want every turbo shop on earth trying to build hybrid ball-bearing turbos and then contacting Garrett for warranty when they blow in the first 10 minutes.

 

[Mr Peepers]

Mitsu turbos are component-balanced, meaning each part is balanced individually prior to installation. What that means is that if he were to find a perfect undamaged TD05H turbine from a 14B, it could rightfully be assembled to any compressor wheel in any TD05H turbo without worrying about the clocking of the compressor wheel on the turbine. I've been building turbos using this theory for years- including those on my own cars and my close DSMies' cars- and haven't had a single issue regarding premature failure due to balance to date. Maybe I've been lucky- but you don't get lucky a few hundred times in a row.

Think of it as balancing a car tire perfectly, and balancing the wheel perfect as well....then rebalancing the whole assembly once you put the tire on the wheel. If both components were balanced before they were assembled, there's no need for the last step.

I've come to find that the only turbos that absolutely require the complete rotating assembly to be balanced are ball-bearing units; which is why Garrett and other companies only sell complete CHRA's for these turbos. Balancing is so crucial to ball-bearing units that they don't want every turbo shop on earth trying to build hybrid ball-bearing turbos and then contacting Garrett for warranty when they blow in the first 10 minutes.

Thank you for clearing that up, I've been wondering about that for a while. Every time I see something about rebuilding a turbo they always say make sure you mark the orientation of the wheel to the shaft. Not trying to dispute what you're saying at all, it just didn't make sense if they were individually balanced in the first place.

EDIT: found some more info:
One way was to balance the turbine wheel and shaft and the compressor wheel as a single unit. The other way was to balance the turbine wheel and shaft the compressor wheel individually. You can tell how the balancing was done by the shape/appearance of the COMPRESSOR nut. If the nut appears to be ground down then the turbine wheel and shaft and the compressor wheel (and nut) were balanced together. If the nut is not ground down then the wheels were done individually. If the wheels were done individually then it is not absolutely necessary to mark them and get them in the same location as they were prior to removal. In the case of the "ground down nut" turbo, it is a good idea to keep the wheels lined up in their original positions.