What can cause a "new" turbo to toss the compressor nut?
10-31-2011, 04:11 AM
#16
Burning Brakes
10-31-2011, 02:37 PM
#17
AutoX
Join Date: Sep 2011
Location: North Carolina
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
heated installation and preload
Something to check is if the compressor wheel was properly installed on the shaft. You'll have to ask the shop howey did it (maybe be careful how you ask so they tell you before you let on what you know).
The comp wheel needs to be heated up for about 20 minutes at about 275degF. Within 5 minutes install the comp nut with 5 Nm torque. After the wheel cools a bit, turn the nut 1-2 times to realease and re-tighten with 1 Nm. Finish tightening with 50 deg rotation.
They would have had to heat the wheel to get it on the shaft, though a nut with improper preload would be vulnerable to backing out. I'd be interested to hear how they did it.
The comp wheel needs to be heated up for about 20 minutes at about 275degF. Within 5 minutes install the comp nut with 5 Nm torque. After the wheel cools a bit, turn the nut 1-2 times to realease and re-tighten with 1 Nm. Finish tightening with 50 deg rotation.
They would have had to heat the wheel to get it on the shaft, though a nut with improper preload would be vulnerable to backing out. I'd be interested to hear how they did it.
10-31-2011, 05:07 PM
#20
Nordschleife Master
10-31-2011, 07:22 PM
#22
Burning Brakes
Thread Starter
Just to recap. Three days after buying the car the boost was dropping and I found a foreign object in the j-boot and a thrashed compressor.
Unfortunately my DIY rebuild failed miserably. Primarily because I could not find a proper rebuild manual and did not now of the proper procedures. Reading John's and scotter8's posts I definitely blew it on these points; no heat, improper spacing between turbine and CHRA as well as wrong torque on the compressor nut.
After that I figured I'd play safe and get a shop rebuilt unit so I would not have to do the job ever again. That is the unit we're discussing here. It only managed 1500km or 1000miles.
So completely different reasons for all the failures as far as I can see.
Yep clockwise it is.
Unfortunately my DIY rebuild failed miserably. Primarily because I could not find a proper rebuild manual and did not now of the proper procedures. Reading John's and scotter8's posts I definitely blew it on these points; no heat, improper spacing between turbine and CHRA as well as wrong torque on the compressor nut.
After that I figured I'd play safe and get a shop rebuilt unit so I would not have to do the job ever again. That is the unit we're discussing here. It only managed 1500km or 1000miles.
So completely different reasons for all the failures as far as I can see.
should be left to tighten. bebbetufs, is that what you see?
Last edited by bebbetufs; 11-02-2011 at 02:14 PM.
11-01-2011, 08:07 AM
#24
AutoX
Join Date: Sep 2011
Location: North Carolina
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
i think the hard thing about assembling a rebuild is rebalancing - even if asssembled to spec. the rebuild shop should have the capability?
Last edited by sns951; 11-01-2011 at 09:05 AM.
11-01-2011, 01:19 PM
#25
Burning Brakes
Thread Starter
Clockwise to tighten, and they definitely have balancing equipment.
The turbo was shipped back today. Now all I can do is to wait for their reply.
The turbo was shipped back today. Now all I can do is to wait for their reply.
11-02-2011, 07:49 AM
#27
Burning Brakes
Thread Starter
Not that I can remember no.
How can I make sure this never happens in the future? I'm sick of turbo troubles!
Is it simply a question of having good injectors and a good tune?
How can I make sure this never happens in the future? I'm sick of turbo troubles!
Is it simply a question of having good injectors and a good tune?
11-02-2011, 09:20 AM
#28
Addict
Rennlist Member
Rennlist Small
Business Sponsor
Rennlist Member
Rennlist Small
Business Sponsor
Does your car have a past history of sexual offenses? In some societies the punishment for that was removal of the offender nuts…. (sorry – couldn’t resist that one)
If this is a repeat problem I would take a very close look at the threads on the shaft – if the same shaft is being reused the threads may be damaged and unable to hold torque. The loose nut bouncing around the compressor could have easily damaged the threads.
If this is a repeat problem I would take a very close look at the threads on the shaft – if the same shaft is being reused the threads may be damaged and unable to hold torque. The loose nut bouncing around the compressor could have easily damaged the threads.
11-02-2011, 01:03 PM
#29
Burning Brakes
Thread Starter
Thanks for your input Chris.
It is impossible for me to know as the rebuild shop select their parts from their parts cache and then assemble a turbo. The core I sent in had a damaged turbine shaft and was trash. It is not unthinkable that the shaft of the rebuilt turbo had been over torqued at one stage in it's life, but there is no way I can verify that.
It is impossible for me to know as the rebuild shop select their parts from their parts cache and then assemble a turbo. The core I sent in had a damaged turbine shaft and was trash. It is not unthinkable that the shaft of the rebuilt turbo had been over torqued at one stage in it's life, but there is no way I can verify that.
11-21-2011, 06:58 AM
#30
Burning Brakes
Thread Starter
I just received a phone call from the people who supplied my turbo. They admitted to having made errors in assembly which caused the nut to spin off. I have to say I was rong in my assumptions about this company and that they seem like a much more respecatble company than I first thought.
Next step is to see if they will cover some of my work and one-time-use materials like gaskets, lock nuts etc, but this is secondary to getting a replacement turbo.
Next step is to see if they will cover some of my work and one-time-use materials like gaskets, lock nuts etc, but this is secondary to getting a replacement turbo.
