Free spinning turbine shaft

[Neveragain55]

One last question about the turbo gang and I’m done I promise

 

Everything is put back together to spec and I have used all of the correct parts, seals, and fluids.

 

The turbine does spin freely, the problem I’m having is with the term “spin feely†as it could be vague and subjective.

 

The turbine shaft spins but stops rather suddenly after I spin it by hand or by air.

 

It doesn't stop abrupty, but it doesn't spin much past the point where the force to spin it is gone.

 

It’s not binding at all (that I can tell) but it doesn’t seem to spin and decrease in spinning speed until stopping the way any other rotating object would. (think spinning wheel raised of off ground)

 

Are these turbine shafts designed to be this snug and stop suddenly once the rotating force is off of them, or have I over tightened something causing the shaft not to spin as freely as it should?

 

Keep in mind I am using the original “Journal Bearings†style bearings, and also that I have spun the shaft before and after putting the end nut on with the same results. I’ve also checked to make sure that the compressor wheel isn’t sitting to tightly up against the base, and it’s not.

 

In other words, everything is as it should be, and the shaft does spin, but it seems a little to snug to me and I’ve never put one of these together before so I just wanted to get some feedback from those of you that have.

 

Thanks…..

Edited April 9, 2012 by Neveragain55

[SleeperZ]

There is drag from the seals and low mass. I've never seen a turbo spin long after spun by hand.

[Neveragain55]

Thanks so much Sleeperz,

 

That what I figured because nothing is binding it at all and there is no debris what-so-ever in the housing.

 

Thanks for the quick reply........

[dexter72]

I bet after you drive the car and check it again, It will spin easier than it does right now.

 

I started my engine up after a co-worker rebuilt my turbo. I was kind of bummed that my turbo didn't spin when first running and revved. I took the car for a quick road test. Checked it while the engine was running again, and it was spinning at Idle.

[Neveragain55]

Thanks Dexter72,

 

I'm new to rebuilding Turbo's and I've learned a lot from all of you.

 

It came out really nice. I vapor blasted everything, got all the surface rust off of everything, soaked the parts, cleaned them out all very well, and then I used POR 20 to paint the center and exhaust housings.

 

It's actually looks too good to go back on the car but the last glitch was the turbine shaft.

 

I replaced the original with a new one because I discovered that the old shaft had a slight bend in it.

 

Like I said in the previous post, it spins by hand and by compressed air but it stops sort of quickly once the force to make it spin is gone and I was wondering if that was normal.

 

Now I'm super confident that it is.....

 

Thanks again....

[JSM]

 

It came out really nice. I vapor blasted everything, got all the surface rust off of everything, soaked the parts, cleaned them out all very well, and then I used POR 20 to paint the center and exhaust housings.

 

 

Does POR last long on a turbine center section?

[Neveragain55]

We're gonna find out.............

 

I did a little research and tried to find out what the operating temperatures of the center section, and the tolerances of the POR 20 were before I put it on.

 

Without writing a book on the subject in this small space, suffice it to say "the experts" assured me that the silver high temp POR 20 (which is what I used) will in fact hold up.

 

I also individually baked all the parts (before the new bearings & ring clips went in) in my oven to cure the POR 20 because it will never air dry.

 

You have to cure the stuff onto whatever you applying it to if you want it to stay.

 

I've seen dozens of cats rebuild turbo’s pouring hundreds of dollars into them, just to put all the rusty, ugly components all back together again when they were done.

 

Yes - I realize the rebuilt internals matter more than the appearence, but still.................

 

Why go through all of that and still have an eyesore when you’re done.

 

The worst that will happen if it doesn't hold up is that it will flake up and eventually peel off, but it won't affect the performance at all because it's all on the surface, not the inside.

 

Like I said, we'll see

 

 

I attached pictures of what it looks like, I put POR 20 on the exhaust manifold as well ....

Edited April 10, 2012 by Neveragain55

[Xnke]

I wouldn't have painted that CHRA behind the turbine shield....that'll flake off for sure, and will lay there, chewing at the turbine shaft at 100,000RPM...

[Neveragain55]

I thought about that but.........

 

If I have to pull it all apart after a few thousand miles or more, what the hell, lesson learned.

[letitsnow]

The BBQ paint on my manifold has held up pretty well, it can be seen glowing at night after a 1st-4th run.

[Neveragain55]

Here’s my analysis:

 

This is what I used which can withstand temperatures up to 1400 degrees.

 

http://www.marine-paint.com/merchant.mvc?Screen=PROD&Product_Code=P20&Category_Code=HiTemp

 

I’m assuming this is what Letitsnow used which can withstand temperatures up to 1300 degrees.

 

http://www.google.com/products/catalog?q=BBQ+Black+Satin+High+Heat+Paint&hl=en&cid=10205419845842435948&ei=z6uDT5q1D8OisAfc5IzoCg&ved=0CAcQ8wIwAA#p

 

Letitsnow has stated that the BBQ paint has help up pretty well thus far and that would fall in line with what the experts told me about POR 20.

 

If the BBQ paint is rated at 1300 and POR 20 is rated at 1400 then I think I’ll be ok…..

[letitsnow]

Yup, that's the stuff, but I used a spray can. You should be good.

[Neveragain55]

Thanks dude, I'm hoping so..........