KKK K24 Turbo disassembly

[16V-Sauger]

is it predictable what temperature that steel can handle?

[fspGTD]

16V-Sauger - are you talking about Nickel - Chromium 202, the turbine housing material?  It seems like someone should be able to find out the temperature limit of it, but I'd still wonder if something else in the combustion chamber or high-temperature exhaust stream might melt or fail first!

[16V-Sauger]

the problem is, i would like to use one of my T3 on a 2L 16VT gasoline  :twisted:
i'm only driving that car ~3000miles/year. so if one would work for a year i could use that 3 turbos for around 3 years :lol:

i was told that in the past the turbos all came from one factory line, diesel and gasoline. would make sense, causing less costs. so older diesel turbos should work on gassers.

can anyone confirm that?

[HarryMann]

They might come from the same line, but unlikely the turbos are the same between petrol and diesel, far too many differences, exhaust gas flow/temps, rpm band etc. Could be wrong (newbie here!)

is it predictable what temperature that steel can handle?

Temp lints of these high-temp type steels are defined by a Creep Vs Temp plot. They don't just give up, but their working range is defined by how much creep under stress can be allowed (creep is stretch or strain under load) Typically Ni-Cr-Fe alloys used for stressed components might work in the range 650-750C, but here the component is not stressed so much as having to retain dimensional tolerances at high temps, which variations on these alloys can be designed for.

That bearing seal though, doesn't look like steel, looks like phospor-bronze to me.

[Hey]

In the first page, it is said:

This will raise boost by simply not allowing the wastegate to open all the way and will send EGT's way up.I would leave that ajustment alone Or put a bigger spring in the wastegate.So for anyone else looking to raise boost on the k14,k24 the best way is to just put a bleed in the line or use a boost controller, just leave the screw alone!

I have a k14 turbo on my 1994 jetta 1.9TD, it looks like this turbo:



I played with the rod that is in a red circle on the picture above. I screwed it farther and the got the boost to 12psi(was 9 before).

According to what have been said, it will raise the EGT!!!  Could someone explain it to me because I don't really understand. Usually, when we want to raise the boost, we want the wastegate to stay close at greater psi.

What is the difference with not allowing the wastegate to open all the way(playing with the screw) and a boost bleed???

Thank you!

[fspGTD]

When the wastegate can't open enough to precisely regulate the boost pressure where it cracks open at, it will allow the boost pressure to "creep" upwards an additional amount after the wastegate has already cracked open, which is generally not a preferred scenario.  Compared to a wastegate that precisely regulates an equivalent peak boost pressure, the boost creeping setup would have weakened horsepower and torque in the middle RPM area (especially right above where the wastegate cracks open), which is generally where you would otherwise find peak torque on a wastegated turbodiesel.  On a well-regulated turbo-diesel setup, the RPM area right after the wastegate opens is also generally where you'll find peak operating efficiency, and is generally the most useful powerband area in most street driven applications.

I generally agree with Andy2's quote above, that the KKK internal wastegate adjutment screw is not a very safe or desireable way of increasing boost by anything more than a very modest adjustment.  That is, unless you are trying to keep the wastegate completely shut at all times, in which case this can be easily accomplished by simply turning that screw all the way in.

[LeeG]

Bringing this thread back from the dead.
I bought one of Jakes kits long ago (he shipped it fast!)
Finally I am getting roundtoit.

So I have it apart as shown, got the bearing out of the compressor side.  Down in the hole is a circlip.  Does it have to come out before I pound the shaft through?  I can't really see what it does in there.  A couple exploratory taps left me thinking there is still something holding it in.

BTW, does anyone have a couple of the C shaped clips that the bolts holding the compressor housing goes through?  Part #2 here: http://www.turbomaster.info/mascara_dibujo2.php?modelo=TAO3&nombre=&marca=

[QuickTD]

Never "pound" the turbine shaft. It should come out at this point. The piston ring seal is either hung up on slight groove in the bearing housing or the bearing is "coked" up and stuck to the shaft. If its the piston ring, gently wiggling the shaft in an orbit within the housing will generally get it free. If the bearing is coked up, some carb cleaner and time might help it free up.

[fspGTD]

Hey Lee - glad to hear you are making progress with the kit install.

For where you are in the process, I would advise setting up a piece of wood onto a hard floor, and then holding the bearing housing in both hands with the shaft pointing straight down, moving the assembly straight down into the wood, tapping the end of the shaft onto the wood.  The inertia will help jolt the turbine sealing ring free.

For additional protection of the shaft end, it is not a bad idea to thread the compressor nut on there flush with the end of the shaft so it spreads the load from the impact.  Be sure to do the tapping with the shaft pointed straight down and moving the assembly straight down, do not tap sideways on the shaft.  It should knock right out.

[LeeG]

Thanks for the help guys, got it out.  
A 2 day soaking in carb cleaner helped break up the crud and made things considerably looser.  It still needed a couple of light taps to get it out.  (Did I say pound!?  Must be the redneck in me - fix it with a BFH, then read the instructions!)  
For this turbo the carb cleaner soaking was an important step... before that I had wacked it a couple times with a block of wood and it wasnt going anywhere, after soaking, 2 light taps and out it came.

Anyhow, here is the culprit that was holdin it in, wear groove at arrow:
(click for bigger picture)



And there was this solid buildup of carbon outboard of the bearing that was contributing to the 'zero play' feel before I soaked it, making me think that I had missed some fastener.  There was enough chunks to convince me it went all the way around:


And finally, a question.  Is that just carbon in the groove?  (red arrow)  Is there supposed to be something in there?

(white residue = non abrasive silver polish, took the carbon off axle quite nicely)

Getting this apart has been kinda fun.  Like most fancy stuff, its a lot less imposing once you get the parts all spread out.  We'll see how it goes back together and if it works.

[zooky]

And finally, a question.  Is that just carbon in the groove?  (red arrow)  Is there supposed to be something in there?
.

I'm at the same point in my rebuild, I cleaned out that groove (looked just like yours), that carbon is tough! Chuck it in a drill press (slow speed and dont tighten too much) and lightly run a scotchbright pad up and down the shaft, that does an excellent job of getting the crud off and breaking the glaze and leaves a nice cross hatch like you do for cylinder walls. Rebuilding a turbo is fun, alot easier then I thought. Now I can cross 'turbo' off the list of components I am afraid to mess with :wink:

[ODwyerPW]

Do you still sell the kits?  I will need one around Jan or or so.

[fspGTD]

Yep - that is old, crusty, really hard carbon in there.  It's designed with that lip (which isn't part of the sealing surface)... to try and "fling" the oil off the rotating shaft.

I would be very careful chucking the shaft into a drill, not to mar the shaft surface.  But, scotch brite does do a good job of cleaning it up.  You can get the big chunks off by "chipping" away with a razor blade (be very careful not to cut yourself!)

Using an old sealing ring (they snap in half) also works well as a ring groove scraping tool.

Odwyer: Yes I still sell the kits, and I currently have some of the Dieselicious 1.KKK 6lTD K24 kits in stock.  IM or e-mail me when you're ready to go, and I'll send you ordering instructions.

[zooky]

got the rebuild done, there was nothing to it. It was no more difficult then doing rear brakes. Took like 3 hours including cleaning and painting. I should have taken a 'before' pic, it was nasty! My turbo is as good as new for under $100 (rebuild kit + paint/carb cleaner). Thanks again fspGTD for an affordable kit. For those of you thinking of rebuilding your turbo, its pretty strait forward and can be done in an afternoon, just becareful for broken housing bolts...

[Maarten]

Since you completely took apart the KK K24, you may be able to have a solution for a problem I have:

I'm putting a AAZ into a VW T3 Transporter but I have some clearance problems with a enginesupport and the turbo... I need 2-3cm extra space under it, thats where the wastegate is.

In the previous car where the engine with that turbo was running I completely closed the wastegate to get max boost, so I don't really need the wastegate assembly to be on the turbo.

Now the question is, do you think it is possible to close the hole of the wastegate somehow?