omega0684
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| posted on 20/5/09 at 08:43 PM |
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turbo dismantling
hi guys, my mate with the astra turbo coupre came round today and gave me his turbo! hey i said what have you done? ive had the VXR turbo fitted so
you can have it  ka ching! only problem is that the oil seal has blown on it and now it needs replacing
i started dismantling it about half hour ago and i cant split the turbo in half,how do i do this, i assume that the only thing holding it together is
the turbine shaft
alex
[Edited on 20/5/09 by omega0684]
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prawnabie
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| posted on 20/5/09 at 09:02 PM |
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I think you need specialist tools to put the two housings back together?
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indykid
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| posted on 20/5/09 at 09:07 PM |
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how far have you got? any pics?
i trust you also marked the shaft, impeller and impeller locknut before disassembly to maintain balance when you put it back together? it's a
left hand thread on the shaft too
tom
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omega0684
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| posted on 20/5/09 at 09:18 PM |
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i havent done anything to the impeller yet the turbo is still in one piece, all ive done is remove the actuator and the screws for the housing, i will
go take some pictures, 2 minutes
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jpindy3
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| posted on 20/5/09 at 09:21 PM |
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i dont think you need to balance it to change the seils,if so there is a good place called cr turbos i can find the number if you want,also get a
explodid diagrm.
good luck
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omega0684
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| posted on 20/5/09 at 09:32 PM |
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ive done them in big so they are more clear
     
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mark chandler
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| posted on 20/5/09 at 09:48 PM |
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Although interesting from a taking apart perspective for performance I think you may be wasting your time with that.
Its a low pressure turbo, and hideously restrictive if you peer down the exhaust inlet.
If you screw it up I,ve got one you are welcome to for the postage, inlet vanes are a little mashed though.
Regards Mark
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dinosaurjuice
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| posted on 20/5/09 at 10:04 PM |
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my DIESEL engine has a bigger turbo than that
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omega0684
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| posted on 20/5/09 at 10:10 PM |
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im not intending to use it, i want to repair it and sell it! there has got to be some dodo on the vauxhall forums that will need one
this is the VXR Turbo its about the same size astra the 2.0 z20let turbo but apparently produces more boost
[Edited on 20/5/09 by omega0684]
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MikeRJ
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| posted on 20/5/09 at 11:00 PM |
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Before you do anything else mark the relative positions of the inlet and exhaust housings with respect to the "core" of the turbo so you
can put it back together at the right angle.
Simply undo the bolts going into the side of compressor and turbine housings and you should be able to just tap the housings off. Then you are left
with the bearing housing, turbine and compressor to dismantle.
I made a jig so I could reassemble to turbine and compressor in the same relative locations, as popular internet mythology says this is a good idea.
The compressor is quite a tight fit on the turbine shaft, obviously be very careful with both compressor and turbine wheels as it's easy to
damage them.
I reckon half the reason the bearings went on mine was the large build up of carbon on the back of the turbine which must have been affecting balance;
I soaked the whole thing in white spirit for a few days (all I could find) and then carefully scrubbed it clean with a plastic scraper and small brass
wire brush.
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BenB
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| posted on 21/5/09 at 10:05 AM |
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I'd read a few books on forced induction before bothering taking it apart. You really need to make sure it's the right size for the
intended use. The size of a turbo is quite a precise requirement. Too small and you'll strangle the engine (and possible lose power), too big
and you'll get horrible lag with stupid power on boost which you'll have to vent (or blow up your engine!!)....
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omega0684
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| posted on 21/5/09 at 10:18 AM |
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quote:
Originally posted by BenB
You really need to make sure it's the right size for the intended use.
not intending to use it mate, just repair it and sell it, they are going for £150-200 on the astra forums
[Edited on 21/5/09 by omega0684]
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MikeRJ
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| posted on 21/5/09 at 10:47 AM |
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quote:
Originally posted by BenB
too big and you'll get horrible lag with stupid power on boost which you'll have to vent (or blow up your engine!!)....
You never have to "vent" boost apart from dump/bypass valves during gearchanges etc. The wastegate is used to control boost.
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indykid
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| posted on 21/5/09 at 03:12 PM |
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never seen a turbine housing integral to the manifold before. it's an unweildy beast isn't it!
i work with holset truck turbos all day, on placement, so little stuff like that's a bit alien to me.
as mike said though, mark orientation of end housings relative to the bearing housing, unbolt and tap the housings off. be careful taking the comp
cover off so you don't damage the impeller. the turbine wheels will take a bit of abuse but the impellers are fragile.
mark the orientation of the shaft, impeller and locknut relative to each other. the rotor is balanced on a VSR and gets balanced by nibbling the nut.
it's quite important it goes back on pretty close to where it was originally.
you'll need tiny circlip pliers if you want to change the journal bearings. i've used gedore J0 pliers for rebuilding a garrett T25,
they're just small enough once you take the paint off the tips.
use the circlip pliers to spread the piston rings on the turbine end of the shaft when removing them. scratching the shaft with a screwdriver is bad.
if it's double ringed, use the circlip pliers to put the rings back on too. don't open them too much and sprain them though, just enough
to get them over the boss.
there's a fair few turbo rebuild guides on the internet and the insides of a turbo are all pretty similar.
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MikeRJ
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| posted on 21/5/09 at 04:21 PM |
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quote:
Originally posted by indykid
mark the orientation of the shaft, impeller and locknut relative to each other. the rotor is balanced on a VSR and gets balanced by nibbling the nut.
it's quite important it goes back on pretty close to where it was originally.
Question: why do they balance the turbine by grinding lumps out of the back of it, but grind the nut to achieve the same on the compressor? Since
the nut has such a tiny radius and mass compared to the compressor wheel, it must have quite a small effect on the overall balance.
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jpindy3
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| posted on 21/5/09 at 06:20 PM |
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forced induction
performance tuning
by Graham Bell
iv just started reading it,good so far
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BenB
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| posted on 22/5/09 at 08:03 PM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by BenB
too big and you'll get horrible lag with stupid power on boost which you'll have to vent (or blow up your engine!!)....
You never have to "vent" boost apart from dump/bypass valves during gearchanges etc. The wastegate is used to control boost.
Yes, but it controls boost when you're making too much by venting it
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MikeRJ
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| posted on 23/5/09 at 02:01 PM |
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quote:
Originally posted by BenB
Yes, but it controls boost when you're making too much by venting it
It doesn't vent boost, it simply allows some exhaust gasses to bypass the turbine which slows down the compressor and reduces boost.
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indykid
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| posted on 23/5/09 at 11:18 PM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by indykid
mark the orientation of the shaft, impeller and locknut relative to each other. the rotor is balanced on a VSR and gets balanced by nibbling the nut.
it's quite important it goes back on pretty close to where it was originally.
Question: why do they balance the turbine by grinding lumps out of the back of it, but grind the nut to achieve the same on the compressor? Since
the nut has such a tiny radius and mass compared to the compressor wheel, it must have quite a small effect on the overall balance.
both parts are balanced beforehand (comp wheels on the edges and boss, and turbine wheels on the back face and star driver) to quite tight tolerances,
but when assembled , the nut is taken as the balancing plane to remove any residual unbalance from the assembly due to the additon of other thrust
parts like thrust collars and oil slingers.
tom
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