I purchased a used set of N3G1 twins and am questioning their condition. The primary turbo compressor wheel seems to have a lot of shaft play. No in and out motion, but a good bit of side to side movement. Also, when the compressor wheel is spun on either turbo, the fins often make contact with the black seal inside the housings and make a screeching noise. The seller told me that was normal because the turbos do not have any oil pressure on them.

Can someone with more knowledge on this topic chime in on the below videos? I got a good deal on these and would love to run them on my car, but fear I've bought a worn out pair.

Here is the video of the turbo with the most up and down shaft movement: https://photos.app.goo.gl/VHXdUCbNqc5t9bwy6 (once you open you have to click on the video thumbnail too)

Here is a video showing the shaft play as well as the noise when the compressor wheel is spun: https://photos.app.goo.gl/gJ2pfN8W9rayusyM6

Same video on the other turbo: https://photos.app.goo.gl/iESn383VNYnpogAP6

Sorry for the crap quality videos. Thank you all for your help.

 

That does seem more than usual. You may have a bad set there unfortunately. Used turbos are always a roll of the dice.

May want to get with Bryan at BNR Supercars and see what it would run to rebuild them.

There is normally some play due to the space for oil in the bearings but that's more than usual.

Dale

 

Thank you Dale. Would it be worth while to prime these with oil and see if that changes the shaft play at all? Or anything other than shaft play that could indicate that they need to rebuilt? Just trying to get the facts straight before going back to the seller.

 

When journal bearings are running at speed and high oil pressure, the rotating assembly rides on a thin film of oil. This will center the rotating assembly a little bit, but that amount of compressor wheel rub is indicative of a worn and bad turbo.

Priming with oil won’t make a big difference.

 

I agree that priming with oil pressure and retesting won't make much of a difference. If there's any metal-to-metal contact in the axial or radial directions, that turbo is ready for a rebuild.

 

The rule of thumb for "compressor touches the housing" assumes the clearance is roughly equal to acceptable play.
99 spec's use the compressor wheel to wear the plastic insert meaning they're designed to touch. This results in less clearance and ruins the "ruler" we are using.
You can check the static clearance with a feeler gauge to estimate how much it's worn.
Not sure what a good spec is, but I think there are additional considerations because these are 99 spec turbos.

 

FWIW I just bought a used set of 99s with supposedly 60k miles. They have an identical level of shaft play and make the same metal on metal grinding sound. Dont know if this helps at all as we may both have bad turbos, but yea.

 

Thank you all for sharing your wisdom, I appreciate it!