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AAZ with VNT that gets stuck every 1300miles
by
Apsik
on 21 Dec, 2007 17:36
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Hi
I have an AAZ with GT2052v on it
(topic here) and now I have some problems with vanes for the 2nd time since october
Since october I did 2500miles max
1200miles ago I noticed slower boost increase and I cleand the vanes because they were barely moving/working. After that everything was OK.
2 days ago I noticed that problem again, I checked the vanes and they still moving but I have to use some force to move them full scale.
Tomorrow I'm gonna take the GT20 out and clean the vanes... again.
Do you have any other solution for taht or maybe "how to prevent that problem"??
It's winter so working on it 3h every 6 weeks isn't handy :cry:
I have 10mm pump and 1,1bar of boost - the smoke it generates looks like that:
http://www.youtube.com/watch?v=IECTWFjA_NMI'm guesing that it could be because of the smoke (sometimes i'm accelerating rapidly).
Last time I noticed that when I have the GT20 splited the vanes itself works OK but the flat surface behind the rotor (where the thinny ring works moving vanes) is full of the black dust and that's the only thing I have to clean. That surface has the 1st contact with the hot exhaust fumes.
Any ideas?
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#1
by
jimfoo
on 21 Dec, 2007 17:46
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The smoke is probably a big part. How are you controlling the vanes? Do you ever get your EGT's very high?
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#2
by
Apsik
on 22 Dec, 2007 03:17
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How are you controlling the vanes?
The answer is here:
http://vwdiesel.net/phpBB/viewtopic.php?t=11014&postdays=0&postorder=asc&start=0Do you ever get your EGT's very high?
The EGT gauge is on the way to me as we speak. I've ordered Auto Meter EGT gauge (USA).
The smoke is probably a big part.
I gues so ... should I adjust the pump or the mbc?
I have not yet had a chance to install them (as you can see). I will report back when I do. I should have the 300TDT up and running in the next week or so, but if there were going to be any vane sticking issues, I would not expect them to show up for several months.
In my opinion the problem is on the other side of the vanes carrier. I mean the side where you can find the thinny ring that moves all vanes. When I split the turbine I dont't have to disasemble the vanes carrier I just clean the surface begind the rotor with a brush, than that thiny ring and it's done.
I noticed that behind the rotor is some kind of a round plate ... maybe during assembling my turbine I positioned it bad leaving some space so the carbon get there??
Any idea?
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#3
by
jtanguay
on 22 Dec, 2007 04:35
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VW engineers made the VNT turbo's work quite well on the TDI's without much issues. One thing they added was at the beginning when you turn on the engine, the vanes are actuated to their fullest extent a few times. you can do this by flooring the pedal a few times before startup. i believe the engines also actuate fully at shut down as well. it would probably be a good idea to do it while the engine is running to blow out any 'crud'. blipping the pedal shouldn't be too harmful?
this is one reason that i've wanted to create a standalone electronic vnt controller. two inputs: boost & TPS. no messy linkages, and boost could controlled quite easily and adapted for aggressive/mild driving.
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#4
by
jimfoo
on 22 Dec, 2007 06:59
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I wonder if something like a very thin layer of anti-sieze might help keep the carbon from sticking? Just a wild guess. I'd use the nuclear grade in a turbo due to the heat.
NICKEL SPECIAL, NUCLEAR GRADE
The standard in the nuclear industry, Never-Seez® Nickel Special, Nuclear Grade is specially tested and certified pure for use in nuclear power plants. Each production lot of Never-Seez ® Nuclear Grade is tested for contaminants of sulfur, halogens and low-melt metals and each container is labeled with the lot number that certifies purity.
Never-Seez® Nickel Special, Nuclear Grade is recommended for nuclear fittings, valves and steam mani-folds. Provides maximum protection from high heat up to 2400ºF and aggressive chemicals. Meets General Electric D50YP12, Westinghouse and Bectel's nuclear specifications. Tested to MIL-A-907.
DATA SHEET
Product Applications:
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* Steam generators
* Assembly of dissimilar metals
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#5
by
Apsik
on 22 Dec, 2007 07:47
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VW engineers made the VNT turbo's work quite well on the TDI's without much issues. One thing they added was at the beginning when you turn on the engine, the vanes are actuated to their fullest extent a few times. you can do this by flooring the pedal a few times before startup. i believe the engines also actuate fully at shut down as well. it would probably be a good idea to do it while the engine is running to blow out any 'crud'. blipping the pedal shouldn't be too harmful?
this is one reason that i've wanted to create a standalone electronic vnt controller. two inputs: boost & TPS. no messy linkages, and boost could controlled quite easily and adapted for aggressive/mild driving.
Quite a good point - why just after turning the engine vanes goes "full open"
I have to try to floor the pedal a few times before startup maybe that's some kind of vnt cleaning trick.
That side of my friend's VNT has not had any buildup or caused any problems. The sticking of vanes on the VNT quantum has been quite certainly from buildup of carbon on the turbine housing and vane carrier on the side where the vanes are located
Last time I was working on the vanes I even polished them so they were shiny. Vanes and the big ring they are attached to.
I wonder if something like a very thin layer of anti-sieze might help keep the carbon from sticking? Just a wild guess. I'd use the nuclear grade in a turbo due to the heat.
This may do the trick on the surface behind the rotor because it's cast iron and the surface is very rough. Coating it with layer of anti-size stuff would be a wise thing.
I gues i'm gonna make some use of my credit card
if they will ship it to Europe.
http://www.neverseezproducts.com/nuclear.htmDo I need any special equipment to do the coating?
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#6
by
jimfoo
on 22 Dec, 2007 08:15
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I wonder if something like a very thin layer of anti-sieze might help keep the carbon from sticking? Just a wild guess. I'd use the nuclear grade in a turbo due to the heat.
This may do the trick on the surface behind the rotor because it's cast iron and the surface is very rough. Coating it with layer of anti-size stuff would be a wise thing.
I gues i'm gonna make some use of my credit card if they will ship it to Europe. http://www.neverseezproducts.com/nuclear.htm
Do I need any special equipment to do the coating?
It's just a paste that brushes on.
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#7
by
Slave2School
on 22 Dec, 2007 09:42
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Just a simple question/statement. Won't grease type lubrication attract more soot?
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#8
by
jimfoo
on 22 Dec, 2007 11:28
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I doubt it unless it gets globbed on. I was thinking just a very thin coating.
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#9
by
jtanguay
on 22 Dec, 2007 11:41
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what about that silicone spray you can get for keeping the door from sticking in the winter??? silicone can withstand high temps, and shouldn't attract the soot (well not much of it anyways)
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#10
by
Tintin
on 25 Dec, 2007 06:20
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I had the same problem with my mechanically controlled VNT20, I have to open it some times to clean it, but the last time I removed some material on each vane :oops:
On a factory TDI, the vane do not move any time when you start the engine, it moves only one time to go positioned in full boost, when I check if the VNT work well on a TDI, I put a finger on the vane lever, and somebody starts the engine, it move one time but with much force, more than a mechanical linkage.
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#11
by
Apsik
on 26 Dec, 2007 07:05
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I had the same problem with my mechanically controlled VNT20, I have to open it some times to clean it, but the last time I removed some material on each vane :oops:
Now the problem is solved?? Do you have any pictures??
I can clean my VNT each 1300miles, but we have winter now and working on it @ -10*C in my garage isn't a pleasure job
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#12
by
Tintin
on 26 Dec, 2007 09:23
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Removing material from each vane will accomplish the same effect as adding longer spacers to shim the vane carrier plate away from the turbine housing and allow the additional space for the vanes. I actually just completed this task on my VNT25 a couple of days ago. It was actually more involved than I thought, but less work than trimming each of the vanes, IMO. Also, would be reversible if desired. I'll post pics in my Merz thread in the next day or so...
Andrew
Yes yes, your solution It's much more easy, and that done a much more beautiful work.
For me, when I make the "grind" :oops: job, I did not have a spacer in stock and I wanted to reinstall the turbo asap, but I do not remove much material, only a little grinding-clean.
I do not recommend to anybody to grind the vanes, it were to give my example.
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#13
by
DonGTI
on 08 Jan, 2008 13:04
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Curious... Did you block off the EGR valve?
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#14
by
Apsik
on 08 Jan, 2008 13:47
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Curious... Did you block off the EGR valve?
Ages ago
BTW. that nuclear anti-sieze paste is on the way to me
with some AutoMeter guages
... no matter what
you have some gr8 stuff in US