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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: boogiethecat on May 18, 2009, 12:47:47 AM

Title: turbo went poof
Post by: boogiethecat on May 18, 2009, 12:47:47 AM
I blew my turbo last weekend as I was halfway up the Baker grade.  I'd noticed on this trip that I was only getting half the boost I normally do but didn't think it would  be anything more than a dirty air filter.  Instead, suddenly everything went to hell in an instant... lost power, so much smoke spewing out the exhaust that with the slight wind that was present I couldn't even see the freeway in front of me...eeek 

But whatever it was, was not catastrophic- oil pressure was good, the engine sounded fine, temperature was fine... just no power and lots of black smoke...LOTS
So I kept going as there was an offramp at the top about 2 miles away  Got to the top going between 1-2 mph in first, that's all it would do, blowing so much smoke that by the time I got to the offramp I had a personal CHP escort and evidently more than a few motorists had called in 911 telling them I was on fire.
In the end all it was is the rotor shaft seal went away, the rotor stuck, and the engine was left all choked up and running on massive quantities of crankcase oil.  Once I got to the top I had to use the compression release to stop it, as it was running solely on it's own enigne oil and shutting the fuel off did nothing to stop it.  After thanking the officer for the escort (he was very happy I made it off the freeway) I took it all apart, hammered out the rotor (messed up the blades, too bad), stuck a bolt in the shaft hole to seal the inlet and exhaust sides from each other, put it all back together and completed my trip.
It was a bit ugly tho for the rest of the trip... all that restriction and no turbo at 5000 feet got me honked at or flipped off about every 15 minutes for the cloud I was blowing!!  But other than needing a lot of new turbo parts, nothing else went wrong. Lotsa greasy work to do now! Unfortunately I'll probably have to buy a new set of wheels and shaft as well as the bearing assy but I'm sure it'll be less than a tow job would have.   

  Funny this was the first trip in 30,000 miles that I didn't bring ALL of my tools.  Ended up having to mickey mouse and wedge the exhaust rotor into one of my wheel holes to get the thing unscrewed, as that is usually a job for a vice.  And I had a few things held together with welding wire by the time I got her going again... but at least I had enough tools and parts to plug the oil line and take it apart, and not have to call a towtruck.

I'm SO glad I have a compression release.  Without it I'd have blown the engine up in a runaway when I finally got it restarted, as there was soooo much oil left in the intake that I couldn't reach to clean out.  So I started it from the engine's service controls with my foot firmly on the compression release lever, and it REALLY tried to run away, and spewed me with gook from head to toe as it slowly evened out.  What a mess!!!  Glad I'm happily home now, and all I have to do is wash the engine down, and send the turbo up to Don Fairchild to get repaired.

I'm left wondering what happened to the turbo... I bought it brand new from Garrett maybe 20,000 miles ago.  Shouldn't have crapped out that soon!!!

Fun with the Crown!!!


Title: Re: turbo went poof
Post by: JohnEd on May 18, 2009, 01:04:51 AM
You are So cool!
Title: Re: turbo went poof
Post by: jackhartjr on May 18, 2009, 03:45:04 AM
Boggie...not saying this is/was you problem...however...a lot of folks are prone to run hard...then shut the engine down without letting it cool down for at least three minutes.
When you shut it down without the cooldown you have oil in the turbo seals that can be 600 degrees plus.  With the cooldown is is more like 300 degree oil or less.
The heat in the turbo in my opinion causes most turbo failures.
Jack
Title: Re: turbo went poof
Post by: boogiethecat on May 18, 2009, 08:16:03 AM
Yeah I'm aware of that one Jack- I always let her idle a few before shutdown.

It was interesting when I first installed it... I originally put it in the same line as my oil pressure gauge, and it read 25 psi as if the turbo was just a big leak.  But it spun, worked and sounded fine.  Then in it's first 5 minutes of operation it suddenly went to zero pressure.. I kinda freaked out, pulled the bus over and checked, oil was flowing fine but now there was no backpressure at all.  It still worked fine so I drove it home.

Thinking the problem, if any, was just the the turbo was at the end of a 4 foot 1/4" line and since my oil gauge was at the same point, that probably explained the zero pressure reading.  So I then moved the supply hose to it's own own oil gallery hole and took it off of the oil gauge line... the gauge came back to it's normal 50psi and everything was fine for the next 20000 miles.

  Back last year when I took my Jakes off and had Don Fairchild help me put in a new rear axle and the Telma, Don was looking at the turbo and noted that it's shaft felt somewhat sloppier than he thought it oughta be, but I told him it'd been that way from the git go and he said, ok, and it works fine, so no biggie.

I guess there was some biggie but I have no idea what... I'm thinking it's been bad since day one and just finally gave up
Title: Re: turbo went poof
Post by: NJT 5573 on May 18, 2009, 09:56:35 AM
I always hold the impeller with my fingers for about 30 seconds when I install a dry turbo, just to make sure I don't kill the bearings. (Don't let it spin until your sure it has oil). Sounds like the first place it was plumbed was not enough volume to keep it alive, if it was prelubed properly when it was installed.

If a turbo has the proper amount of oil going to it and the seals let go, they can burn all the oil out of the pan in a very short time. The next question is, how much oil did it take to fill it back up and are you headed for more problems? I have put 4 gallons in a Cummins when the seals let go and I ran it less than 60 seconds.
Title: Re: turbo went poof
Post by: boogiethecat on May 18, 2009, 02:13:42 PM
Hmmm.  From the amount of smoke it was blowing, I'd have thought I was using massive quantities of oil.
But it was 2-3 quarts in about an hour.  I guess that probably isn't a decent indication of how much oil the turbo was getting all along though,
because there's no way to tell how much of the seals were blown and how much oil was going back into the pan vs into the intake manifold...

I'm guessing that my oil pressure is fine going to the turbo; 1/4" line only about 2' long hooked into a 50 psi oil gallery...

Cheers
Gary
Title: Re: turbo went poof
Post by: Zeroclearance on May 18, 2009, 05:28:28 PM
Gary, was there FOD damage to the turbine wheel??   I would assume that you had compressor wheel rub?

The 2 main methods of failure are going to be oil supply, either lack oil pressure> high oil temperature (no cooling)>fuel dilution>oil contamination

And lastly, foreign object damage>> something impacting either the compressor wheel or turbine wheel.   With the two cycle it usually is something hitting the turbine wheel  (rings, pistons, exhaust valves, exhaust piping or failed welds).
Title: Re: turbo went poof
Post by: johns4104s on May 18, 2009, 06:19:50 PM
What checks can do to be sure the turbo is good? is there any need or is it possible to grease or oil the Turbo?

John
Title: Re: turbo went poof
Post by: JohnEd on May 18, 2009, 06:29:51 PM
I'm guessing that my oil pressure is fine going to the turbo; 1/4" line only about 2' long hooked into a 50 psi oil gallery...

Not the Boogie I have come to know and love!

Another possibility is that the return line is plugged.  Not hard to check.  I would want to hear "I have X#psi at the turbo".  Course, I ain't the Monkey crawlin 'round inside there.  Makes a big difference with that wish'n stuff.

Good luck Boogman,

John


Title: Re: turbo went poof
Post by: boogiethecat on May 18, 2009, 07:54:19 PM
Yeah, I thought oil pressure at the turbo would be a good way to make sure things were right, but when I tried that and the gauge said zero I asked the guy at the turbo place and he said it wasn't necessary, just hook it up and go.  Later on, about 8000 miles ago, Don F also looked at it and said it oughta be fine too.
So I couldn't get a straight answer back in those days and I was very new to it all; it appeared to work fine and that was what I had to go on.

BTW the place I bought it was Diesel Services, Inc. in Grand Junction and the experience with those folks was less than favorable.  They charged me $1500 for it because it was a custom build for my application, then they shipped it to me in horribly poor packaging, and when I got here it was all bent up (wastegate assy got crunched 'cause there was basically NO packaging other than a too-large box)
So I asked for a replacement which they begrudgingly sent, but at that point I was a bad guy and they basically quit talking to me.  That's one reason I couldnt get a straight answer, and unfortunately at that time I hadn't met Don Fairchild or any of you.  Oh well...

I'll check the drain line but I'm sure it's ok... it's only 6" long and 1/2 inch in diameter.  IF something plugged that up, i've got much worse problems!!!
When Don gets through with it, maybe we'll know more....


Oh... there was no wheel damage.  It just slowed down and eventually stopped but nothing rubbed that I can see.

Cheers
Gary
Title: boogiethecat: I'm Sorry You Blew Up Your Turbo
Post by: HB of CJ on May 18, 2009, 08:32:28 PM
Aren't you lucky the older 743 Cummins has the manual compression release?  My old Crown with the Small Cam 855 also had one.  The mechanic showed me how to spin the mill to build up oil/fuel pressure and stuff.

Would your Jake Brake have allowed you to physically shut down the Cummins?  Reason I ask, my planned new Crown might have the Big Cam Cummins, which as far as I know, doesn't have the compression release.

Which would mean, if the turbo seals blew like what happened to you, there would be no physical way to shut down the mill from eating its own lube oil, running away and blowing up sky high?  Would a Jake prevent this?

Years ago, the old school bus Crown I drove had the Jake set up sossss if you had it turned on (single stage) and had the tranny in neutral and released the clutch pedal, the idling engine would instantly stall.

The master mechanic told me they set it up that way, but I forgot the exact reasoning why.  Anyway, could the Jake Brake clutch micro switch be set up to instantly stall a runaway engine?  HB of CJ

Title: Re: turbo went poof
Post by: boogiethecat on May 18, 2009, 11:08:22 PM
Yeah the Jakes would have killed it... as would dumping the clutch in 6th which was another possibility although I never like to stop an engine that way...

Good to hear from you HB!
Title: Re: turbo went poof
Post by: Zeroclearance on May 18, 2009, 11:19:49 PM
There are really no health checks for the turbo.   I tell folks the very first sign of trouble is oil showing up in the intake piping.   The exhaust will blow past the turbine side seal (similar to a piston ring blow by) and pressurize the bearing housing blowing oil out the compressor side (thru the comrpessor side seal (similar piston ring).    If you take the turbo off the engine one can measure the bearing wear.   But with the amount of labor that requires, one can install a new center cartridge.

If infact your turbine and compressor wheel did not have FOD damage, then the bearings need to be looked at.   If you oil drain is plugged, then fresh oil cannot enter the bearing housing freely to lubricate and cool the bearings.    Fuel contamination will also trash the bearings.   I'd get a oil sample.   

Title: Re: turbo went poof
Post by: JohnEd on May 18, 2009, 11:52:28 PM
Boogie,

Forgive me if I am belaboring this.  The zero psi at the oil inlet would have spelled disaster to me.  I sympathize with your not having any grounding in this....neither do I.  Lots of gas stuff over the years though.  If there is zero psi at the input what reason would the oil that is there have in going thru the turbo?  The input can't be plugged as you were pumping oil into the intake and burning it as fuel.  Very strange stuff here......it can't all be true at the same time....me thinks.  There is that word again, "think".

Really look forward to hearing Don's take on this.  Not to mention Sherlock Holmes. ;D  This is no time for levity.

John
Title: Re: turbo went poof
Post by: gyrocrasher on May 19, 2009, 12:13:38 AM
Quote from: JohnEd on May 18, 2009, 11:52:28 PM
  This is no time for levity.

John
:D :D :D :D
Title: Re: turbo went poof
Post by: boogiethecat on May 19, 2009, 07:43:25 AM
I agree John.  I took the oil pressure thing as "no backpressure in the turbo" rather than "no oil pressure", and as it was, it ran fine for 30,000 miles.
I have to admit that I did wait 10000 miles between my last oil changes, maybe that killed it but that's hard to believe...

But when the oil thing first became apparent (that was in the first minute of it's operation) I pulled the oil feed hose and cranked the engine over for a second, and got totally blasted with oil.  So I thought to myself, "well, there's so little backpressure in this turbo that at the end of this line there's no pressure....and it is a free flow kinda thing, so it must be ok"... I then called Diesel Services and they said it was fine... so I moved the turbo to it's own oil gallery connection, checked it the same way and it flowed fine, my gauge started working correctly again, and away I went.  Until last week anyway... :)

Mysteries...
Title: Re: turbo went poof
Post by: JohnEd on May 19, 2009, 09:27:49 AM
Boogie Meister,

I certainly agree that if the thing was not getting ANY oil it would never have gone 30,000 miles....except simply being carried as freight. :D

I don't think that 10K between the first oil change would have caused it either.

"AhHa!"  Said Sherlock at that Paul Harvey moment.  "Oil went everywhere" would have been my clue, as it was yours, that there was oil getting in there and copious amts that were doing the lube AND cooling job both.  For future reference, and my personal edification, should there have been ANY oil pressure readable at that point with 50 psi available?

That is the scary part to me.  With your having disconnected the feed line and giving her a crank....I would have done "exactly" as you did.  And that is not to be patting myself on the back as i think you are pretty savy.  What it really means is that I would have come to the same END.  That I don't like.  If possible, I would like to learn something from your dismal experience that gives me a measure of confidence that I would be less likely to repeat your journey. Something beyond "beats the shi## outta me".  No doubt, you pheal the same way.  I know you will share.

Thanks for the info and a great story,

John

Title: Re: turbo went poof
Post by: NJT 5573 on May 19, 2009, 10:43:41 AM
Gary,

If you only lost a few quarts in an hour, that is not a typical loss of oil with a turbo seal failure in my experiences.

I haven't worked on a 220 in a long time. I walked out in the shop to look for a 220 oil cooler because the later Cummins group favored plumbing the Turbo from the cooler with # 6 aeroquip. I didn't spot one, they are probably buried behind 20 years of parts, but the thought was if you are plumbed off the cam bearings, you may be short on supply. You may even have worn  cam bearings or have turned a cam bearing. If I remember right when that happens the 220 will stop oiling the rockers directly above it, (or east or west of it with a pancake engine).

While the turbo is off, why don't you start it and see what the feed line will pump into a jug. I think we use to pass/fail test them by seeing if they would hit the ceiling with force in a 20 foot tall shop.

Another thought about the 220 lube setup if I remember right is if the valves are real loose, you will lose pressure at the galley pickup point because they will let excessive oil flow to the valve springs. If you like to run the valves a little on the loose side, you may want to snug up the ones close to where you are picking up the turbo oil supply.
Title: Re: turbo went poof
Post by: boogiethecat on May 19, 2009, 05:35:26 PM
Hmmm interesting ideas NJ I'll try it and see what happens.  At least the oil in a jug thing :)

I'm taking my oil off a gallery under the engine that's hooked right to the lines coming in from the oil filter (remote)
so I'd guess it's a good spot.  There was a 1/4 npt plug there, and in the same gallery a few feet back is where the oil pressure gauge hooks in.

I'll let you know how much I can squirt in the next few days!

Cheers and thanks
Gary
Title: Re: turbo went poof
Post by: NJT 5573 on May 20, 2009, 11:43:17 AM
Gary,

I was thinking about your pickup. Its been awhile since I had a Luber Finer apart, but it seems like they have a heck of a small restrictor in the T handle, maybe .050 or something. Both your turbo and oil filter could be mostly unrestricted. When you check the output on the turbo line before you put it back togather, why don't you check the return line from the filter and make sure it looks somewhat restricted so you can keep some pressure on the Turbo bearings. If you have a Luber Finer, make sure that the restrictor is still in the T handle.
Title: Re: turbo went poof
Post by: boogiethecat on May 20, 2009, 06:17:21 PM
Boy I'm lost on this one NJ....

I don't think I have a luber finer in there... what is there is this:

Oil pump exits into a 1"id hose which goes to an external full flow cartridge style (Napa Gold) filter.  From that filter it goes back thru another hose to feed the main engine oil gallery, from which I tapped the turbo line, and farther down it is where the oil gauge taps off.  There's 50-60 Psi in that gallery, and if I block the turbo hose with a gauge, that's the reading I get at the end of it.  I can't imagine that I'm starving it.  I do remember when I checked it's flow years ago, it squirted all over me like crazy.  Probably would have hit that 20 foot ceiling!~  So there oughta be plenty of flow.
The shaft's bearing surface doesn't look burned, or even hot...

Time will tell, it's on it's way to Don's this weekend...

Thanks for the thoughts!!!

Gary