 |
924Board.org
Discussion Forum of 924.org
|
| View previous topic :: View next topic |
| Author |
Message |
931Owner
Joined: 14 Feb 2009
Posts: 352
Location: Chicago NW Suburbs
|
|
| Back to top |
|
 |
flosho
Joined: 01 Jul 2004
Posts: 3160
Location: Eau Claire, Wisconsin
|
 Posted: Tue May 05, 2009 5:03 am Post subject: |
 |
|
Well considering that picture isn't of a k26 for a 931, I'd ask some questions to the seller.
Although if they are selling the k26 hybrids with the 951 center section maybe it'd be worth it.
_________________
[This Space For Rent] |
|
| Back to top |
|
|
ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
|
| Posted: Tue May 05, 2009 5:04 am Post subject: |
|
|
I have no experience with that reseller. However, I am going to repeat some advice I recently exchanged with another member via PM, as it is certainly relevant to your inquiry regarding the purchase of ANY second-hand 931 turbo, rebuilt or not.
| ideola wrote: | Unfortunately, looking at it [or viewing photographs that were taken] from the outside, you can't tell whether the turbine housing or wheel are damaged or usable. EVEN IF the seller claims it is rebuilt, DO NOT TRUST that it is usable and undamaged.
The most critical part of the whole assembly is the turbine housing itself, and the turbine wheel. Everything else can be replaced or repaired at reasonable cost if damaged, but the turbine housing is totally unique to the 931, and is REQUIRED due to the unique 3-bolt flange for attaching to the 931 manifold. Unless you're prepared for the time and expense of fabricating a custom manifold, you MUST have the 931 turbine housing, and therefore, you MUST also have the 931 turbine wheel & shaft (which is a single integrated unit) [note that the early 951 K26 turbine shaft is a direct fit replacement, and therefore used 951 K26 units may be a good source for turbine wheels should your 931 turbine wheel or shaft turn out to be damaged].
If the housing on that unit is cracked, it's only good as a core. If the turbine wheel on that unit is damaged, it's only good as a core. I would not pay any more than $50 for ANY 931 turbo unless the seller agrees to disassemble the hotside, and provided detailed high resolution photos of the INSIDE of the turbine housing, as well as the inside edges of the turbine wheel. There is absolutely NO WAY of inspecting these with the turbo assembled, as you can not see the areas where the damage occurs because it is deep within the turbine housing. Here are some photos that show the areas you need to be able to see:
  
The cracks in the above photos are actually not so bad, and this particular turbine housing was reusable. But what happens on most 931 turbine housings is that the cracks are uneven on one side or the other, and they interfere with the turbine wheel, destroying the inside edge of the fins on the wheel. Again, you CANNOT see this damage by inspecting the turbine wheel from the outside. I have seen many many turbine wheels that appear great from the outside, only to open up the turbine housing, and discover that the inside portion of the fins that are hidden from the outside are complete chewed up and destroyed.
It is VERY EASY to remove the hotside, there are six bolts that come out, and the turbine housing can be slipped off of the bearing housing, providing easy access to the interior areas that need to be inspected, as well as the turbine wheel itself. That's all that needs to be done, and once inspected, it can be easily re-assembled. The bolts don't even have to be torqued down upon reassembly, just finger tightened because you will need them to be loose in order to properly index the assembly upon installation onto your motor. So bottom line, opening it up is really no big deal. The seller may be hesitant or unwilling to open up the turbo. If so, this is a red flag, and I would walk away.
So, for the unit in question, it's definitely worth looking into, but if I were in your situation, I would NOT pay any more than $50 unless the seller agrees to take off the hotside and photograph the areas I depicted above, and also the entire turbine wheel. This is the only way to know if it's worth buying or not. Hope this helps, and good luck! |
FWIW, JMHO. YMMV.
_________________
erstwhile owner of just about every 924 variant ever made |
|
| Back to top |
|
|
931Owner
Joined: 14 Feb 2009
Posts: 352
Location: Chicago NW Suburbs
|
| Posted: Tue May 05, 2009 5:35 am Post subject: |
|
|
ideola - thanks for the advice and as usual pictures tell 1000 words.
So what would be 'fair market value' on a turbo that you have been able to look at internally?
Would you recommed someone with the tools and mechanical ability to rebuild their own turbo? Or should that be left up to the pros?
_________________
1980 Turbo
-too many cars and too many motobikes |
|
| Back to top |
|
|
ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
|
| Posted: Tue May 05, 2009 6:52 am Post subject: |
|
|
First things first, Flosho is right, that is no 931 turbo in their picture. I would be highly skeptical until I saw photo documentation that they actually have the correct 931 turbo unit with the 3-bolt hot side flange.
If they do, and if they can document that the hotside is uncracked, well, I'd jump all over it, because those are as rare as unicorns from everything I've seen. If the hot side is cracked, but the turbine wheel is undamaged, it's still a calculated risk because you don't know if the turbine wheel was repaired / replaced during the rebuild, and when that hotside heats up, the turbine could be damaged right from the start.
As for rebuilding, I can only recommend John Walzel at Majestic Turbo. He has seen at least a half a dozen hot sides from me alone in an attempt to get two good turbos built, so he knows exactly what to look for, and he can advise you as to whether the turbine housing is reasonably safe to use. His standard rebuild charge is $325, for my money, no question that I would have him do it as opposed to attempting it myself. Very few hobbyist have the correct tools or environment to correctly and safely rebuild a turbo (IMO). You might be able to do seals yourself, but assessing whether the shaft is OK, doing any necessary balancing, all out of the realm of a home mechanic. If these turbos weren't so hard to service in situ, it might be a different story, but the labor required to remove it alone justifies the cost of doing it right the first time (again, JMHO).
_________________
erstwhile owner of just about every 924 variant ever made |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
924 FAQ (Technical)
