inside a GARRETT GT2260V VNT turbo... a DIY

[netercol]

so.. a controversial subject at the very least, i decided to do this peek at a diesel vnt turbo's insides with the understanding that the opinions expressed here are MINE and mine ALONE!..
under no circumstances should you attempt to follow this diy if you are not an EXPERIENCED (hardcore) diy'er.. and even then understand that YOU are taking sole responsibility for the health of your turbo and engine..
also understand that opinions vary vastly on the merit of even attempting this kind of repair, even on this very forum.. you have been warned!!

ok, on to the turbo.. the garrett vnt turbo's are used by bmw on their turbo diesels, specifically for their excelent response characteristics..
although most turbo's can be rebuilt, garrett themselfs do not recommend rebuilding these (vnt spesific!!) turbo's for one very specific reason : the vnt mechanism.

the stroke and movement and total movement of the vnt vanes gets very precisely calibrated in the factory using a flow bench and is unique to every turbo. so garrett feels that once the turbo has been dissasembled, these precise settings will be lost.

my PERSONAL feeling regarding this is, as long as the vnt mechanism is not disturbed or in any way adjusted, and is in perfect condition, and of course provided the exhaust turbine, shaft and compressor is in perfect condition, thus not affecting the balance of the components, it is feasable to treat this turbo like any other, and do a successfull rebuild of the bearing section.

my personal experience has been as follows : i have freshened the bearings on both of my e46 330d's , the bearings in my own car have now lasted 100k with minimal wear, the bearings in my other car has now done 25k.
i have done my previous 320d , and two friends 320d's with no failure , i have also done one 320d with catastrophic failure soon after.. reason for this was that the impellers have already touched sides on this turbo, meaning that the assembly was way out of balance. i replaced the bearing out of curiosity to see what the result would be.. a new turbo was the only cure for this car..

anyways , enough with the disclaimers.. on to the stripdown..
it goes without saying that this needs to be done in a very clean environment.. and components need to be very clean when assembled..

item one, a genuine garrett superkit, for the GT series turbo's, under which falls the vnt turbo's..

the turbo being stripped, a GT2260V from my e46 330d ..

circled in red, the vnt adjustments.. NEVER ADJUST THESE!!

remove the circlip securing the actuator arm, and the two bolts holding the actuator to the housing..

remove the turbo feed, note there is a copper washer on each side of the banjo fitting, dont lose these..

remove the oil drain to sump..

remove the bolts holding the exhaust housing first..

this part can be a problem.. hold the turbo with the exhaust housing hanging down,gently tap the housing on all sides with a hammer untill it lets go.. be sure not to let the housing release unequal, pinching the impeller inside can damage it!
this should be what it looks like after the housing has been removed..

the vnt mechanism..

remove the circled bolts to remove the compressor housing..

compressor housing removed..

note the arrowed seal, replace this with the correct one from the kit.. remove the circled nut holding the compressor impeller to the shaft..holding the exhaust side nut with something suitable.. REMEMBER THIS NUT TURNS CLOCKWISE TO LOOSEN! also use a t handle with socket so as not to put strain on the shaft and possible bend it..

with the compressor removed, gently tap the shaft end to pop the exhaust seal and the complete shaft from the bearing housing.. remove the four circled bolts to remove the compressor backplate..

shaft out..

pop the thrust bearing from the housing, underneath you will see the bottom half of the thrust collar,

remove the collar and underneath you will find the bearing and its lock..

on a well maintained turbo (clean oil) the bearing and its lock should simply fall from the housing when turned upside down.. new bearing on the left, old bearing on the right..

the compressor side top part of the thrust collar and seal.. gently remove and replace with the correct one from the kit..

the exhaust wheel and shaft.. remove the seal arrowed, and replace with correct one from kit.. use fingers only to put the new seal on!!

slide the correct bearing supplied into the housing, with a new lock, new bottom half of thrust collar, new thrust bearing, note thrust bearing oil feed to bottom, replace arrowed seal from kit..

fit compressor backplate with top part of thrust collar with new shaft seal and housing with a new seal, using new bolts supplied..

the tricky part.. fit the bearing housing to the exhaust housing.. taking GREAT care not to disturb the vnt ring.. the dowel circled has to fit its hole, while the actuator arm has to fit its hole.. make sure everything moves as it should afterwards!!!

and voila, a vnt center with fresh bearings..

like i said, i know a lot of people will disagree with doing this at all, if you are one of these , please just view this writeup as a interesting view into a turbo.. if you are one of those that itches to try this out, remember the rewards can be big, but the price of failure just as big
please dont attempt if you dont understand the risks involved..

 

[Whacko]

Good post, thanks for sharing. We've done quite a few in the Uno turbo days. Can be done.
:thumbs:

 

[Rooi_Willie]

Excelent port!

Sent from my GT-I9100 using Tapatalk 2

 

[Andy1GP]

Wow this is fantastic! :ty: and raise:

 

[Philip Foglar]

Very very interesting - since these are the general weak spots of a turbo, at least to my knowledge, this makes a lot of sense if done carefully and properly! :thumbs:

 

[Raybimmer]

:thumbs:

 

[moranor@axis]

awesome writeup as usual :rollsmile:

 

[Dhp507]

Great stuff netercol - But why did you not give the items a good clean before assembly.

Also how do some of the companies esp in the Uk hybrid these turbos?

Is there no one in SA that can offer the same without going the route of importing one

 

[Spy007]

Nice right up. What was the cost of doing this?

"i have also done one 320d with catastrophic failure soon after.. reason for this was that the impellers have already touched sides on this turbo, meaning that the assembly was way out of balance."


Just thought I would post pic of my failure. not taking anything away from this DIY.


Just to add. The mechanic that fitted this turbo Billed for A NEW TURBO. but fitted a RECON.

Turbo lasted 8 months and 9000km.

 

[netercol]

Great stuff netercol - But why did you not give the items a good clean before assembly.

Also how do some of the companies esp in the Uk hybrid these turbos?

Is there no one in SA that can offer the same without going the route of importing one

some of the pics was taken before cleaning, others after.. also no point in making it shine, so long as all mating surfaces and inner parts are nice and clean..

dont know of anybody in sa that can build hybrids of these turbo's..
it involves fitting a higher flowing compressor wheel, and reprofiling the compressor housing to suit.. but because the gt2260v is already virtually the biggest in the ranges, finding suitable compressor wheels for upgrades is difficult (the thickness of the shaft is less than the normal garrett range)

---

Nice right up. What was the cost of doing this?

"i have also done one 320d with catastrophic failure soon after.. reason for this was that the impellers have already touched sides on this turbo, meaning that the assembly was way out of balance."


Just thought I would post pic of my failure. not taking anything away from this DIY.


Just to add. The mechanic that fitted this turbo Billed for A NEW TURBO. but fitted a RECON.

Turbo lasted 8 months and 9000km.

yeah thats one of the worst failures ive seen.. :sorry:


this is the problem with "reconed" turbo's i think.. they get rebuilt only after they have FAILED!
if a turbo has already failed, touched sides, started making a noise ect, its already too late to do preventative maintenence like above..
in order to return such a failed turbo to as new state, everything showing the slightest damage must be replaced.. shaft, compressor, bearings, seals, sometimes center housing and housings too!
in such a case it would cost the same as a new turbo, thus i think a lot of rebuilder re-use parts that should have been discarded, and so failures like yours happen..
this is besides the fact that there is a lot of unscrupelous rebuilders and just plain shoddy workmanship out there..

i would say if a turbo has failed, 9 and a half times out of 10 it is better to just fit a new one..

oh yes , and to answer your first question, cost of the kit is around 1k when last i bought one.. finding good workmanship.. priceless

 

[Luigi_S]

Aaaaaah. Pics are gone here too....