Building a Race Ready Turbo

[vash_1010]

Well this site has been really good to me, so I thought I would share, the way to really rebuild a turbo. Its alot diffrent than what youtube or a tech articals have posted, and while I know the average guy can't really do most of this, if it helps one person, then I think its time well spent. Not going to go over how to take it apart as that is refrenced all over this site and many others. I would like to show good rebuilding practice. Enjoy!


A few notes*

*The greatest tool never used in an at home rebuild is a feeler guage. Checking gaps in the flinger (seal plate insert) ring, and piston ring (turbine wheel) is key for a quality rebuild.

*Utilizing a vice and, clamping your turbine (Not the fins) removeing and tightning the top nut using a T-handle is best to evenly distribute torque rather than using two wrenches is better on your tail shaft and overall performance.





Before we even get started, use all new Mitsu parts, ebay kits can be had for cheap, and fit fine if you just eye it. Truth is they use poor quality brass, and have loose tolerances. There is a reason your turbo lasted 100,xxx miles, it wasn't done using cheap metal and knock off parts.

*I peice kits together using parts so you will see parts to other turbos in pics, the point is to use quality kits.

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The Tear down, the parts that come out of your turbo say alot about why its blown and not performing.

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Rust is a water issue, usually related to coolant getting into the turbo
if your bearings look like this, you have a problem, deep scaring like this is oil contamination or starving the turbo. Also means machineing if the bearing housing is bad enough

The Clean up

I see alot of people use solvants and elbow grease to clean parts, use a sand blaster on everthing *EXECPT* inside your bearing housing, on your shaft (turbine wheel is ok) the comp. housing the rest needs to be bead blasted, comp wheel, inside in and around the seal, clearing out the carbon, it should look like this

Before

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After

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*Notes

* Sand will tear up your comp. wheel. dont even try. you want the area your bearings ride to be smooth and a bead blast is best. (before the next step)
* be sure to clean out your ring groves
* Nows the perfect time to inspect your housings and shaft and wheel for damage.
* YOU MUST MUST MUST blow all the media out, AND dunk it. Media will tear up your turbo.
* Have at it on the HOT side sandblast. Bead blast the Comp housing.

 

[JusMX141]

*The greatest tool never used in an at home rebuild is a feeler guage. Checking gaps in the flinger (seal plate insert) ring, and piston ring (turbine wheel) is key for a quality rebuild.

Unlike the piston ring in a combustion engine, there should be no measurable gap in the turbine seal. If there's a gap, the sealing surface inside the center housing is damaged and you will need to either replace the housing or have the surface welded and re-machined to the proper tolerance so the seal fits tightly.

Again, if there is any measurable gap, exhaust gas will make it's way into the center housing.

Rust is a water issue, usually related to coolant getting into the turbo
if your bearings look like this, you have a problem, deep scaring like this is oil contamination or starving the turbo. Also means machineing if the bearing housing is bad enough

Um- it's impossible for coolant to enter the main bearing chamber of the turbo unless the center housing itself is cracked. What you're seeing is water that made it's way into the compressor outlet at the j-pipe flange (most likely from a car sitting dormant with the j-pipe removed) and caused the rust on the center housing.

 

[vash_1010]

There is gap between the piston ring *as labeled in the kit* that rides on the turbine grove. It needs to be set in the seal and then gapped to oem. If there is no gap, it is the wrong ring. Read the tolerances it does not say 0. As for when rust is on comp side I said it was water, it was ment to mean if coolant gets in there it will look like that as well. Also it does not need to be welded, .10-.20 rings are used to insure the proper gap. Bearing housing needs to have seal work to insure a snug fit.

Um-

Your comments and imput are more than welcome, lets keep it a discussion, lets not start an argument.

From this point I'll just say, this is how I do it, and its worked for me, this isn't the only way to do it.

Clean up of your Turbine wheel and shaft assembly.

Using a mini lathe lets clean up the shaft.

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At this point we are not trying to remove metal only a polish. Using very fine sandpaper clean up your grooves, and remove any lines (should your shaft have to be machined this will have to be done again. Once cleaned with sand paper, polish using cratex at a med-high setting.

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measure shaft thickness to ensure it will still be in tolerances. Add your wheel and see how it fits. If you removed a little too much metal you may have to run your shaft on a lathe so it will accept a bearing .005-.015 if it goes over .015 the factory spec, it should not be used in your application.

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*Important measure the streightness of your shaft all over. a straight shaft is essential to a good build and it will cause a tight spot in your turbo.

 

[pj91gsx]

All this work and its still a 14b.

 

[vash_1010]

Balencing is critical. Heres hows its done.

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stack up your shaft how it sits in your turbo, with the new flinger and colar.

*Note* There is specualtion on balancing, some say that it is factory balanced and that if you mark lines and match it up when re-assembled that it will remain in balance. While it is true that it is factory balanced this was while it was new. I have tested this myself, and while its a lot better than just throwing it back together, it is still no where near balanced.

I hate to quote from memory but I belive that its a .018g tolerance.

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Let it spin, and see just how bad its off balance, if your shaft is not streight, it will never balance correctly.

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By removing metal from under the wheels, you can achieve a balance. This can take a while as you only want to remove as little as possible at a time

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Back and forth untill you can a balance that is with in tolerances. Here you want to shoot for as perfect as you can.

All this work and its still a 14b.

I agree its a little much, however the processes are all the same, I think whether a 14b or a T-30 attention to detail is key. At least people will know what it takes to rebuild, and have more appreciation for the vendor.... or freelancer. personally I hate working on a TD or TC series. Sometimes they fight you to the point you want to throw them against a wall..

 

[brokedowntalon7]

Whoa, that is a nifty balancing machine. Adding that into the plans for the dream garage.... i wish.

 

[pos4g63]

Where can one pick up a balancing machine like that?

 

[bastarddsm]

I wouldn't bead blast the compressor wheel, compressor housing, or bearing housing. Its just waaay too hard to get the glassbeads out after you have done it. Thats just me and my opinion though.

OP, I have been told by an engineer from BW that the "ballance is off so much after just a little bit of runtime, that balancing them doesn't really matter all that much anyway." What do you think about that?

 

[vash_1010]

I wouldn't bead blast the compressor wheel, compressor housing, or bearing housing. Its just waaay too hard to get the glassbeads out after you have done it. Thats just me and my opinion though.

OP, I have been told by an engineer from BW that the "ballance is off so much after just a little bit of runtime, that balancing them doesn't really matter all that much anyway." What do you think about that?

The truth of the matter is that yes it will fall out of spec, but the logic is you want it to go from perfect ballance to a "a little off" instead of "off" to "No Where near right" your friend is right though it does fall out of spec.

when you bead it you must blast it with compressed air, and then use a dunk tank, its almost like a whirlpool with anti-rust coating and cleaning agents. Then go in with a flexi bore light and mirror and visually inspect.

 

[JusMX141]

Your comments and imput are more than welcome, lets keep it a discussion, lets not start an argument.

What is there to discuss- the fact that this would be better off submitted as a tech article?

 

[vash_1010]

Whoa, that is a nifty balancing machine. Adding that into the plans for the dream garage.... i wish.

They are great and alot better than the mechanical ones that are getting phased out... the good news is that the mechianical ones are becoming availible for alot cheaper....

If only this thing could check facebook.

 

[ed1380]

The truth of the matter is that yes it will fall out of spec, but the logic is you want it to go from perfect ballance to a "a little off" instead of "off" to "No Where near right" your friend is right though it does fall out of spec.

That's why the compressor wheel and turbine wheel/shaft are balanced separately. So that when they change orientation one to another, the rotating assembly stays in balance.

 

[vash_1010]

The Actuator

I see these get reused... and for once, we can reuse something (usually) with inspection

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While removed before you think about doing anthing, using a regulator set to 20psi (diffrent for every turbo model) and air it up hold for 10sec. If you don't use a reg, your gonna have a bad day... 120 psi isn't to friendly Check for leaks Mitsu-actuator's are usually pretty sturdy. however if you get a leak, or worse a cloud of rust shoots out. It should be replaced. *However these actuators can't just be bought at wal-mart the good news is that these too can be rebuilt. Send them in, they come back plated and with new rubber. Cheap. If you can not find a rebuilder, heres something you can try as a last resort, marval mystery oil works, if they paid for a rebuild, do not do this.

That's why the compressor wheel and turbine wheel/shaft are balanced separately. So that when they change orientation one to another, the rotating assembly stays in balance.

This is a time consuming process that IMHO should only be used in larger turbos, this again IMHO is out dated, the flinger and colar is not on the shaft and to me is an improper balance. I've used both styles and I perfer the the digital balance. To each their own.

Tape off your actuator and bead blast, do not get media in your actuator.
*see above pics

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If you sent yours in to be rebuilt, no need to paint, it probably looks gold. They plate to protect the metal. What you can use is the paint used for high temp. It keeps the metal from getting too bad, and the fact that your actuator sits right at the hot side it works, not as good as the plateing but works. it just plain looks good as well.

Turning in for the night guys, thanks for reading

Anyone interested the break down?

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if people enjoy the thread I wouldn't mind showing how I work these.
sorry to get off the subject.

Where can one pick up a balancing machine like that?

It is called a mrv-2 by redat, highly Reccommend it.

 

[pj91gsx]

I wanted to point out something. 1st if the 14b parts were rotor balanced it would be off balance as individual parts correct? 2nd I cant see how the balancing machine you have could be anywhere as good as one that MHI would have the $ to buy. Not saying that is way off, but im sure its not up to par with the balancing equipment they have. Kind of like how MAP checks the balance while the turbo is assembled, shouldnt that be taken in as a factor when trying to get it as precise as needed in a ball bearing turbo. 3rd I know you say balancing is crutial, but i have seen mulitiple 14bs with chewed up or no compressor wheel left that never got thrown out of balance enough to damage any of the internals. Ive also seen 14bs that have been rebuilt after the turbine shaft nut came loose and sheared the fins off. The only turbo i saw that was out of balance was a small 16g that had a piece of a piston or valve got threw it and eat up the turbine shaft to the very center. It took that much to throw it out of balance enough to actually hurt something.

 

[vash_1010]

I think we have two different variations of the concept of a balanced turbo. I don't understand how a turbo that suffers damage on fins (loss of metal) can remain in balance. I am Mitsubishi Heavy Industries, certified, I assure you they would not give certifications to a facility with inadequate equipment. To remain in balance it must not fall out of weight tolerances in relation to each other, (turbine and compressor wheel) In my opinion balancing parts on an individual basis is out dated and should only be reserved for shafts that are too large to use the proper equipment ie T30. Assembly should be balanced as a whole using a flinger/thrust, one piece or what ever your turbo requires. To balance a part on an individual basis does not take in account the oil flinger being used. I see you yourself build turbos, so on this subject we will have to agree to disagree. Thank you for your input. Use red loctite on older models that do not have reverse thread shaft nut, it will be Less likely to back off.

You can throw a turbo together with out balancing and without destroying it, it should " work" however it's better not only for lifespan of a turbo but the efficiency as well.

 

[JusMX141]

You can throw a turbo together with out balancing and without destroying it, it should " work" however it's better not only for lifespan of a turbo but the efficiency as well.

This is 100% true. Without turning this into a major discussion, here's what my research on balancing has uncovered over nearly 8 years of dealing with rebuilds.


Buy a new turbine wheel or compressor wheel from the turbo's manufacturer and it will come balanced. Assemble these parts on a journal bearing turbo and they should be within the manufacturer's balance spec. Certain manufacturers (Mitsubishi included) may choose to balance the assembled CHRA on a Vibration Sorting Rig at full operating speed in order to achieve perfect balance. Turbos balanced on a VSR are noted by balance grinds on the compressor locknut because once the turbo is assembled you cannot get to the backside of the wheel to make balance corrections anymore.

Certain vibrations in journal bearing turbos are "absorbed" by the bearing system...the shaft is basically floating on a pillow of lubrication, so slight vibrations due to a tiny degree of unbalance can be absorbed. On the other hand, the shafts on ball bearing turbos are fully supported by the bearings themselves...so it's absolutely mandatory that a ball bearing turbo be balanced on a VSR in order for the turbo to perform properly and without vibration that may prevent full shaft speeds from being achieved.

VSR balancing is normally done on smaller turbos as these units reach much faster shaft speeds than larger turbos, achieving speeds where small unbalances may cause vibrations which effect shaft speed and turbo reliability. If your compressor locknut has balance grinds it's absolutely crucial that the locknut aligns properly with the compressor wheel upon reassembly. If you're changing the compressor wheel, dispose of the locknut with balance grinds and start over with a new nut.

The VSR makes having a perfectly balanced rotating assembly a no-brainer as it's quite difficult to be sure that the thrust collar and oil slinger remain aligned after assembling the turbo as these parts are contained within the cartridge....although it is possible to balance the rotating assembly as you have illustrated above to achieve what may be a better balance than just assembling the parts, but not quite as good as what a VSR balance can offer.



In addition to what Austin has said above, I too have seen customer turbos with the turbine inducer tips completely melted away in a totally uneven fashion which would surely effect turbo balance and possibly compromise reliability and performance, but many of these turbos had no excessive play and performed perfectly otherwise. In almost every case that I've discovered this damage, the owner didn't even realize there was a problem. Makes you wonder just how important balance really is.

 

[ed1380]

This is 100% true. Without turning this into a major discussion, here's what my research on balancing has uncovered over nearly 8 years of dealing with rebuilds.


Buy a new turbine wheel or compressor wheel from the turbo's manufacturer and it will come balanced. Assemble these parts on a journal bearing turbo and they should be within the manufacturer's balance spec. Certain manufacturers (Mitsubishi included) may choose to balance the assembled CHRA on a Vibration Sorting Rig at full operating speed in order to achieve perfect balance. Turbos balanced on a VSR are noted by balance grinds on the compressor locknut because once the turbo is assembled you cannot get to the backside of the wheel to make balance corrections anymore.

Certain vibrations in journal bearing turbos are "absorbed" by the bearing system...the shaft is basically floating on a pillow of lubrication, so slight vibrations due to a tiny degree of unbalance can be absorbed. On the other hand, the shafts on ball bearing turbos are fully supported by the bearings themselves...so it's absolutely mandatory that a ball bearing turbo be balanced on a VSR in order for the turbo to perform properly and without vibration that may prevent full shaft speeds from being achieved.

VSR balancing is normally done on smaller turbos as these units reach much faster shaft speeds than larger turbos, achieving speeds where small unbalances may cause vibrations which effect shaft speed and turbo reliability. If your compressor locknut has balance grinds it's absolutely crucial that the locknut aligns properly with the compressor wheel upon reassembly. If you're changing the compressor wheel, dispose of the locknut with balance grinds and start over with a new nut.

The VSR makes having a perfectly balanced rotating assembly a no-brainer as it's quite difficult to be sure that the thrust collar and oil slinger remain aligned after assembling the turbo as these parts are contained within the cartridge....although it is possible to balance the rotating assembly as you have illustrated above to achieve what may be a better balance than just assembling the parts, but not quite as good as what a VSR balance can offer.



In addition to what Austin has said above, I too have seen customer turbos with the turbine inducer tips completely melted away in a totally uneven fashion which would surely effect turbo balance and possibly compromise reliability and performance, but many of these turbos had no excessive play and performed perfectly otherwise. In almost every case that I've discovered this damage, the owner didn't even realize there was a problem. Makes you wonder just how important balance really is.

But who knows how long those turbo's would have lasted being out of balance. Once the shaft starts oscillating in the oil cushion, it'll start wearing out the bushings from contact, and it all goes down from there.

 

[JusMX141]

Trust me- most of these examples don't appear to have happened overnight....like this fine specimen which was sent in to repair oil seal leakage:

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[pj91gsx]

Excellent read, Justin. Also I have seen turbines worse than that, that were rebuild and boosted fine. The only one that i have seen that was determental to the internal pieces of the turbo was when a piece of the motor broke and took out all the fins in the center, I had never seen anything like that since. However These fins can only get worse, so i just replace the turbine shaft, or encourage the customer to upgrade.

 

[vash_1010]

First time I've heard someone call it a cartage outside of the professional setting, I think we all pretty much got turbo building down, as far as the importance of balancing, I've always felt it was always better to do it and not have to, rather than have to and not. I hate when they tear giant chunks of the shaft nut or on the screw on comp wheel, makes it hard to get the socket on sometimes.

 

[pj91gsx]

Vash, threads like this are always interesting. Some of us just arent fortunate enough to have a balancing machine, so we have to do without. It would be nice to have a balancing machine for some of these clipped turbine shafts that come in.

 

[vash_1010]

Ironically my name is also Justin, using a welder, ( if you can weld aluminum) weld in the chipped spots and then blend, using a grinder and mini lathe to re-form contour is ideal, I'll post up a how too on fin repair, if you guys would like, I would be interested on your guys method on fin repair. A balancing machine is no where near pratical as it takes alot of space and shafts can be balanced cheap

 

[pj91gsx]

I just sand nicks out of compressor wheels. It helps keep the vibration down, and is better for the balance. The nicks on the inside of the compressor wheel dont hurt as much.