I have twin Garrett GT32's on my twin turbo 318ci Dart. I was changing some things around recently and also had to replace part of the exhaust. I decided that if I was going to modify the exhaust anyway, I would swap out the 2.5" downpipes for 3".

When I had the downpipes off, I checked the clearance on the impellers and much to my dissapointment, I had quite a bit of axial clearance on both turbo's. This indicates that the thrust bearings are worn and on one turbo, this is even causing engine oil to leak into the turbine and blow a bit of smoke.

When I dialled in the amount of oil to the turbo's, I went by the specs I could find from Garrett. I have needle valves in the oil lines (solid stainless steel 8mm hardline) which are set to the correct flow and locked.

Anyone have this issue before? Sucks that I have to get them rebuilt now.

 

Are they journal, or bb turbos?

 

Journal bearing turbos.

 

Other than extreme boost levels, and lack of oil, not too much kills thrust bearings. It's my opinion that with journal bearing turbos you don't restrict oil feeds less than -4 unless you have extreme oil pressure, or it's your last resort in oil control, and even then it's not a great idea.

 

After having the turbos rebuilt, I'll open the needles valves fully. Don't want to have to rebuild them a second time.

Boost levels haven't been over 15 psi, so that's safe.

 

I know on stock GN turbos, if they are too small for the appllication and worked hard, they will kill the thrust.
They also happen to be a Garrett. You can get 360 deg. thrust updgrades that are most likely just a drop in. I know it was on the GN turbo I rebuilt.

It had killed the thrust. It had unrestricted 4an oil feed .

two gt 32s dont seem too small but Im no turbo expert. Base engines hp has a lot to do with if the turbos can keep up.

I would address why you need to restrict oil and fix it so you dont have to .

 

Basically, I restricted the oil feed because I read on some Garrett sheet that I had to.

The turbos haven't been worked very hard yet. I don't drive the car much and it has only seen street duty with a few peaks at 15 psi.

Are those 360 degree thrust bearings easy to do yourself? Balance would be an issue I assume when you put the turbo back together. Even though I might line everything back up to how it was.

 

well, i dont know about your turbos or other Garrett turbos. But many are neutral balance so the wheel orientation doesnt matter.
The stock GNs are neutral.

easy to do. Just have to pull the center section apart. If I remember correctly the thrust plate just fastens to the wall of the center section.

 

Seems like a call to Garrett Turbo would be a cheap way to get the right info and possibly some other parts you might need for the rebuild.

Tom V.

 

I'm never a fan of restricting oil feeds on journal bearing turbochargers. Usually, when there is smoke on new builds, its because people mistakenly run too small of oil return lines, or have horribly restrictive return line paths.

The thing about restricting flow with a needle valve is that it might seem like its ok at cruising around with low engine RPM and shaft speeds, but wide open throttle, high engine RPM and shaft speed, then you might not be providing enough oil at that time. That's where the bearings get beat.

 

Been looking around and decided to source it out. Just gave a guy a call and agreed to bring them in so he can look at them first before giving me a quote.

 

Good luck with your turbo source, let a guy who has done it a bunch of times take on the job.
At the end of the day you should be much happier.

Tom V.