Author Topic: Turbine Blade Failure (Read 5440 times)

saurkraut · « **on:** June 23, 2008, 09:51:46 am »

I was zorching along a county trunk road in the extreme northen reaches of Wisconsin friday evening in the '79 Soot Rocket when I hear something rattle down the exhauste pipe.

I let off on the foot feed, and then apply it again and I notice that I can hear the turbo at 2 PSI boost, and its really singing at 10 PSI. Above that a second harmonic joined in that had a rather un pleasant sound.

Since I've been running stupidly high boost (28 PSI), I figured I had over heated the turbine wheel and lost a whole blade. So I limped 'er in to my weeked destination (European Car Service).

I had intended to change the shocks on the audi 5000, and finish wireing in my 12 gage relayed head light harness for my H4 headlights. You know, a nice lite weekend of wrench twirling.

Instead, it was turbo rebuild time:

This turbine wheel had been in 5 different cars, totaling over 500K miles, so I wonder if a bizillion heat cycles took its toll in metal fatigue.

What amazed me is there was no evidence of heat damage, and only the corner of the trailing edge of one blade had snapped off. It also dinged the first blade down wind of it, and that was the extent of the damage.

Fortunately, there was one more K24 laying around that needed rebuild, so I robbed the turbine and compressor wheels out of that one and put it in mine as I had rebuilt it last winter.

zukgod1 · « **Reply #1 on:** June 23, 2008, 10:19:34 am »

Wish I would have been that lucky when mine went..

anto · « **Reply #2 on:** June 23, 2008, 10:45:57 am »

Did you just put together the rebuilt k24 back in the car without balancing it?
Ive a k14 i rebuilt ready to go back in my car but getting around to getting it balanced is holding me back.

saurkraut · « **Reply #3 on:** June 23, 2008, 10:57:57 am »

Quote from: "anto"

Did you just put together the rebuilt k24 back in the car without balancing it?
Ive a k14 i rebuilt ready to go back in my car but getting around to getting it balanced is holding me back.

I don't believe this to be a balance issue.

If it was out of balance, I'd expect allot more damage as I pushed this turbo pritty hard.

The journal and thrust bearings show no wear. The turbo was quiet, the only time I heard it was when it spooled down from 20+ PSI

I marked the end of the shaft so i could put the compressor wheel back on in the same position it was in. There is a little nerd cast into the compressor wheel for reference. So i expect the ballance was as good as it was befor I took it appart.

anto · « **Reply #4 on:** June 23, 2008, 11:08:17 am »

I wasnt suggesting it was out of balance either more like debris that caused it but where from?

The balancing i meant was in ref to the turbo you had to rebuild due to the failure of the first turbo hot side wheel.

Im kicking myself when i took my k14 apart that i didnt mark the shaft but at the time i didnt know to do that.

saurkraut · « **Reply #5 on:** June 23, 2008, 11:50:45 am »

There was no sign of foreign object damage. I suspect metal fatigue.

There were no marks anywhere on the turbine wheel, except for the trailing edge of blade right next to the one that broke was bent more.

foxracer1 · « **Reply #6 on:** June 23, 2008, 03:58:19 pm »

When i had my T3 balanced they said they balance the wheels separately the indexing with the other wheel or shaft has nothing to do with balancing a turbo. Just my 2 cents. It cost me about $65.

saurkraut · « **Reply #7 on:** June 23, 2008, 04:46:12 pm »

Quote from: "foxracer1"

When i had my T3 balanced they said they balance the wheels separately the indexing with the other wheel or shaft has nothing to do with balancing a turbo. Just my 2 cents. It cost me about $65.

There is a cast-in reference mark on the KKK compresser wheels so I figured it was a good idea to put them back the way they were. I took both the turbine wheel and shaft, and the compressor wheel form the loose turbo as a matched set. There were no signs of wear on the turbine wheel, or the compressor wheel. They both looked really fresh, all except for the coked on oil in the turbine side seal area.

I put them in the turbo with the new bearings, seals, o-rings, screws, and reground waste gate valve seat. I indexed them exactly as they had been indexed in the loose turbo.

foxracer1 · « **Reply #8 on:** June 23, 2008, 05:17:25 pm »

I have heard of some turbos being indexed so i'm thinking the garret doesn't but othets do?

saurkraut · « **Reply #9 on:** June 23, 2008, 05:30:05 pm »

Quote from: "foxracer1"

I have heard of some turbos being indexed so i'm thinking the garret doesn't but othets do?

Don't know for sure, just paly'n it safe.

anto · « **Reply #10 on:** June 24, 2008, 03:34:18 am »

Sorry for being a newbie here but what do you's mean by "indexing"?

foxracer1 · « **Reply #11 on:** June 24, 2008, 07:23:19 am »

Indexing is lining the compressor up with the turbine with a referance mark. I'm not sure how to explain it.

jimfoo · « **Reply #12 on:** June 24, 2008, 08:26:07 am »

Quote from: "foxracer1"

When i had my T3 balanced they said they balance the wheels separately the indexing with the other wheel or shaft has nothing to do with balancing a turbo. Just my 2 cents. It cost me about $65.

When I brought my turbo down to the local turbo shop, he said the old ones were like that, having to be balanced as a whole, but the new ones weren't like that any more. So the story has just been passed down from back when it was true.

anto · « **Reply #13 on:** June 24, 2008, 09:06:55 am »

Quote from: "foxracer1"

Indexing is lining the compressor up with the turbine with a referance mark. I'm not sure how to explain it.

So its basically marking the compressor and turbine at the point where it was balanced?

jimfoo · « **Reply #14 on:** June 24, 2008, 09:35:17 am »

Yes, but any more they are balanced separately, so it shouldn't matter how they are put on as two balanced items should have no way of becoming unbalanced no matter how they are assembled.