Turbo Balancing - Gpop Shop

[misphit]

I'd like to know if anyone has specific experience with the Gpop Shop? I have a few rotating assemblies (e316g, b16g, garrett 57 trim) that I'd like to have balanced and there's not a lot of options for me around here (Ontario, Canada). The only reputable shop that I've found in my area is charging $165/balance

Recently, a turbo that I rebuilt died within 100 miles... it was a complete write off of a small 16g. The turbo shop that inspected it said that it failed because of improper balance. That would make sense since I didn't have it balanced at all - I assumed that everything was component balanced and therefore I didn't make the effort to scribe everything for reassembly. There were no signs of oil starvation or excessive lubrication, so I have to go with what they told me.

Nonetheless, I found the Gpop shop online and was hoping that someone here could attest to their quality and workmanship. Additionally, if you have another place to recommend please do so.

Thanks.

 

[JusMX141]

I've done business there in the past.

Basically any shop that performs the service is going to do it properly. Reassembly isn't rocket science- when you get the parts back you'll literally line up the sharpie marks on the compressor and turbine wheels and you're set. It's the same as if you would scribe the rotating assembly from a previously-balanced turbo on your own.


I still don't believe reassembly of the wheels, even if unclocked, would've caused the turbo to fail within 100 miles...something else had to have gone wrong. With balance there are tolerances just like an engine has oil tolerances and ring gap specs. When the wheels are made new, they are balanced before they ever leave the factory. This level of balance is considered an "acceptable" level at the factory. On certain turbo models the manufacturer chooses to further balance the parts by balancing the rotating assembly to ensure the turbo spins true and without vibration. This additional balancing is essential on ball-bearing turbos where the vibrations of the shaft are not absorbed by the oil film the shaft is riding on.

I've had turbos come to my shop with fins completely missing from one side of the compressor wheel, and they still spooled fine aside from being a little noisy, and didn't have any shaft play. What you're telling me is your "unclocked" turbo had more unbalance than a turbo that is missing an entire compressor fin; so much, in fact, that it failed in less than 100 miles....and I refuse to believe that.

 

[AndrewD5418]

Mitsu turbos are also component balanced...

 

[need2boostpsi]

as already stated...mitsu turbos are component balanced, even if they weren't, that turbo has a small enough exducer/wheel to not cause failure, esp in only a 100 miles.

 

[misphit]

What you're telling me is your "unclocked" turbo had more unbalance than a turbo that is missing an entire compressor fin; so much, in fact, that it failed in less than 100 miles....and I refuse to believe that.

I'm not 'telling' you anything; I'm merely repeating what I was told by the turbo shop. However, it is my understanding that 'component balanced' only includes the balancing of the compressor wheel and turbine wheel/shaft. Any other parts of the rotating assembly (locknut, thrust parts) are not balanced separately but are balanced upon assembly as a whole. No? Are those parts (locknut, etc.) so insignificant so as to not even affect the balance of the assembly?

I'm just asking questions here, not trying to dispute your years of experience vs. my one rebuild Though you might deem balancing as unnecessary, I don't really want to take the chance of something going wrong again... I will gladly shell out the $65 for someone to balance these suckers; mostly because if I sell them, I would like to be sure that I did everything within my power to ensure a good, long turbo life and if something goes wrong then I will have a leg to stand on.

In the future, I will most likely just scribe my parts for reassembly. I have fully disassembled these turbo's without scribing anything hence the desire to balance.

 

[JusMX141]

I'm not 'telling' you anything; I'm merely repeating what I was told by the turbo shop.

Of course they're going to tell you that you're an idiot for attempting to rebuild it yourself without balancing it because they're trying to sell you a balance job.

However, it is my understanding that 'component balanced' only includes the balancing of the compressor wheel and turbine wheel/shaft. Any other parts of the rotating assembly (locknut, thrust parts) are not balanced separately but are balanced upon assembly as a whole. No?

That is correct. This is the difference between a component-balance, rotating assembly-balance, and a core-balance where the turbo is balanced once it's fully assembled.

Are those parts (locknut, etc.) so insignificant so as to not even affect the balance of the assembly?

If your turbo had the core balanced at the factory (noted by grinding marks on the compressor locknut), there's a chance that assembling it with the locknut in a different position or the compressor wheel clocked differently that it would fail....but not within 100 miles.

On larger turbos which operate at a lower peak RPM, balance is less crucial- you'll see more component-balanced turbos on a larger frame (60-trims, Holset HX35's and 40's) than you will 16G's, etc. Many early 14B's were component-balanced only.

You'll see that many of the newer turbos on the market come with a 12-point hex locknut on the compressor wheel as opposed to a 6-point nut. The 12-point nuts are "rounder", and generally spin truer with less possibility of unbalance due to hex positioning.


I'd like to see some pics of the shaft to see if there was any chance that it was an oil-related failure.

 

[misphit]

If your turbo had the core balanced at the factory (noted by grinding marks on the compressor locknut), there's a chance that assembling it with the locknut in a different position or the compressor wheel clocked differently that it would fail....but not within 100 miles.

Ahhhh, and there's the crux of the situation. The turbo that I'm referring to was one that I sold. The seller contacted me shortly after he bought it and informed me that it blew... therefore, I only have his word that it was destroyed within such a short time period. If your opinion is that it couldn't have happened within 100 miles, I can accept that. It doesn't change anything for me, however.

I'd like to see some pics of the shaft to see if there was any chance that it was an oil-related failure.

And I'd love to show you some but I don't have any. All of the contact that I had with the turbo shop was done over the phone; we are hundreds of miles apart. Again, I had to take their word for what they saw. They said that there was no bluing on the shaft or any other parts, if that's what you're after

 

[JusMX141]

The turbo that I'm referring to was one that I sold. The seller contacted me shortly after he bought it and informed me that it blew... therefore, I only have his word that it was destroyed within such a short time period.

...and there's where it gets messy.

Almost a year ago I had a customer who blew his stock T25 beyond repair buy a rebuilt T25 from me. He claimed the turbo lasted (20) miles, but also found out he had a rod bearing failure so obviously the metal was ruining the turbo.

I then set the guy up with a killer deal on a Small 16G which, he contests, blew in less than (20) miles after he got a new short block in the car from DSM Graveyard. He's now blaming me up and down about how shitty of a business I'm running and that all turbos need balanced...you know, because I should take advice on rebuilding turbochargers successfully from the uneducated public.

Obviously there's a reason he went through three turbos in (60) miles, and perhaps it is my fault, so I agree to give a full refund for the 16G before I ever got the turbo back into my hands....foolish on my part. Here's what I found:

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^ ^ That's metal chips in the oil inlet, metal present in the center housing, and a severely blued and scored shaft. This turbo was clearly deprived of oil and / or given an oil supply that was full of metal, and I took it in the ass by letting this guy get away with destroying a freshly rebuilt turbo and then giving him a refund. I don't know if he used the old head on the new DSM Graveyard block or what, but he was getting metal somewhere.

I installed a replacement rotating assembly into the turbo and it's still boosting on a friend's daily driver to this day.


I know it's your word against his, and he's obviously going to make you look like the bad guy for not getting the turbo balanced when you rebuilt it, but there really are a million variables in this situation. I'm still defending that the failure of the turbo you rebuilt is not balance-related.

 

[Rob10_99]

That'll teach ya.

No way in hell I would have given that guy his money back after knowing his rod bearing was going out.

 

[JusMX141]

No way in hell I would have given that guy his money back after knowing his rod bearing was going out.

The 16G was never bolted to the old engine- the one with the bad rod bearing. I figured I was selling him an upgrade that would be bolted to the new engine and last a very long time.

 

[misphit]

I know it's your word against his, and he's obviously going to make you look like the bad guy for not getting the turbo balanced when you rebuilt it, but there really are a million variables in this situation. I'm still defending that the failure of the turbo you rebuilt is not balance-related.

Fair enough.
The situation is already resolved... I refunded him half of what he paid me for the turbo even though I had no obligation to do so. Nevertheless, I managed to keep my good reputation intact (on my local board) and leave the buyer relatively satisfied.

After reading your last post, I am glad my troubles weren't as involved as yours.