Catastrophic Failures

[WillWagner]

I asked Chris if I cuold post some pictures of som ugly failures I see at work. He sid sure, so here are some. We get about 2 to 3 major failures a month, so I'll snap some pics as they come if they are interesting. All of these are in process repairs. I'll try to get them as they come to me so we can see the outward results of major internal failures.

 

[builder77]

Failures like this always make me feel like my engine is a waiting time bomb to self destruct. Which I guess they all are. Anyways are there any pre-failure signs for turbos and such? I am guessing the only real prevention is replacing/rebuilding the turbo when its expected life span is ending. What is the life span of a turbo anyways?

 

[WillWagner]

We have come to the outer limits of turbocharging on the newer engines. Cyclic loading is tearing them apart. The compressor wheels that Cummins is using are machined from solid, meaning, they take a solid hunk of an alloy, not aluminum or stainless, and machine the compressor the way it is needed for the various applications. They say it's more robust, but they are still failing at a fairly high rate. They are turning very fast now. We have speed sensors on the shafts on all the VGT equipped engines. We are seeing 90,000 RPM on some of the engines. Older engines, like the ones we have, the turbos will last a very long time, unless you over fuel the pee pee out of them. I'm more worried about the logn time it takes to get initial oil pressure.

 

[WillWagner]

Here's another. This is what happens when you have NO pre or post use inspections and employees are stupid and can't see coolant on the ground. This WAS in a generator. It was a mechanical engine with a low coolant level sensor installed...they won't work if the bulb isn't in coolant! it was a 400 hz aircraft ground support generator, so it goes to rated RPM at start up and continued to gun 'till the piston stuch and the rod got jerked out the bottom of the piston.

 

[steelsoldiers]

Good pics and write-ups Will. Here's a NHC250 that threw a rod through the block. You know that made a heck of a noise!

 

[WillWagner]

That's repairable!

 

[frank8003]

Time to update the thread

A photo sent to me ................

How about maybe really hook it up and blow it to hard, I don't know.

 

[GUNNUT in Iowa]

Mule engine swap

It was running just fine at an idle and then - not so much.



Hint - that gear should be fastened a little more firmly onto the end of that camshaft.

(or maybe those two parts of that camshaft should be more firmly fastened together.)

 

[jimk]

No surprise we'd get something new from someone with a top fuel avatar. Is it wrong of me to enjoy this stuff? After all it is the suffering of others. My mechanic origin is based on flying cast iron. Mid 60's when is I was 6 or 7 the old man retired an old 2 stroke lawn mower, gave me some wrenches and said have at it. Spent some time turning nuts and bolts w/no idea what I was doing. Took off a small cover and saw a nut inside the crankcase. Turned it a bit but it was hard to get at so put the cover back on. Few days latter the engine stopped with a bang, rod hanging out the side. So began a lifetime of trying to keep engines together.
Link for folks that never saw this "Catastrophic Uncontained Engine Failure" train thing seen on line a few years back.
http://model-railroad-hobbyist.com/node/4229

 

[frank8003]

The avatar is of the US Army car, sponsor for 16 or 17 years now. They used a device that proved the horsepower that they thought they had. Proven at above 10,000 horsepower. There has to be some green in that car someplace.


http://www.goarmy.com/events/army-racing/nhra-top-fuel/dragster.html

 

[breaktime]

study in absurdity

For an apples vs oranges study-

Using your link, Tony's car makes 11,000 HP at 8,500 rpm. Using HP= T x RPM/ 5252 torque is 6,796 lb ft. The Pratt and Whitney R-4360-63A 28 cyl radial was made in the mid 50's and used in the C124 Globemaster II cargo planes. The -63A was the highest HP engines offered for regular service. With Water Alcohol anti-detonation on the power rating was 3,800 HP at 2,800 rpm. Using the equation torque works out to 7,127.7 lb ft.
Top fuel engine endurance varies a lot. For this study lets say the engine last 4 seconds before catastrophic failure. The 4360 TBO was something like 1000 hours. Most of that time it would be running at a lower "cruise" output. The 3,800HP rating above is "take off" or "military power". I have no idea how long that is but for this exercise lets say 10 minutes before the engine starts crying about high cyl head temp. There are 600 second in 10 minutes. Seems to me if these two engine had to fight each other the 60y old radial, loping along at what might seem like a fast idle in the family car, would chew up something like 150 of Tony's screaming nitromethane fueled engines before it starts complaining.

Or perhaps we can find someone willing to couple together 10 warmed over big block Chevys. Running at full throttle maybe they can stall a 4360 at 2,800rpm.

Or maybe, um, wait, I'm rambling, I guess I'll spare everyone and go binge on some u-tube tractor pulling videos.(note -Both examples are torque at red line. Maximum torque usually occurs at a slightly lower rpm.)
photos- Top fuel piston I found in a trash barrel after the 1994 (?) Keystone Nationals. Note crushed crown (hydraulic lock or detonation?), heavy construction, big pin high enough to cross the oil ring groove (I assume for the longest rod possible), teflon (?) coating, button retainers (not in pic), big intake and small exhaust valve...
http://www.hotrod.com/articles/don-...-top-fuel-hemi-with-new-engine-torque-sensor/

 

[quarkz]

Catastrophic failure or rapid disassembly?
When the NHC-250 remote fan mounting bolts aren't tight on the 600 mile recovery trip.
I didn't witness the temp gauge go up, but the front window began to fog and there was a certain familiar sweet smell. You'd think a -Desert Storm- truck wouldn't need that much fluid to run.

 

[frank8003]

catastrophic failure or rapid disassembly?
When the nhc-250 remote fan mounting bolts aren't tight on the 600 mile recovery trip.
I didn't witness the temp gauge go up, but the front window began to fog and there was a certain familiar sweet smell. You'd think a -desert storm- truck wouldn't need that much fluid to run.
View attachment 678600View attachment 678601

ouch !

 

[frank8003]

Oh
There is lots of 'em

https://www.youtube.com/watch?v=ZfttA0mds-c

 

[ranchhopper]

https://www.youtube.com/watch?v=WvMl8LUzQnk I think this applies on a grand scale GE locomotive eats a turbocharger and is running on its own oil.

 

[QUADJEEPER]

That will buff out.

 

[someoldmoose]

My turn on the Sorry, just been waiting to use that one. I'll be the one to stick my neck out and say it. Maintenance, maintenance, maintenance. Check ALL the fluids, all the time (or at LEAST as often as the TM says). Yes, components fail. However, the first things we asked to see when something got dragged in was the work order for the last PM and the daily pre-trip check sheet. Several folks were invited to find new employment with another company after their daily sheet signified everything had been checked and was proper and were then proven wrong. An engine low on coolant or oil WILL self destruct. Anything that rotates, slides, or slips needs lubrication. Do it. Often.

Turbos . . . Number one killer? Lack o' lube. Let the engine idle for a MINIMUM of 3 minutes before shutting down ( I even do this on non-turbo vehicles just so I don't forget when I am lucky enough to get a wheezer for the day). As stated above, these things spin ridiculous fast and their only "protection" from rapid deceleration due to friction is the lube oil. If the engine is shut down before the shaft cools the oil will actually turn to "coke" inside the bearings. Next start-up . . . no lubrication and BANG, new turbo time. This can also occur over time. Let the engine idle. I suggested putting "turbo timers" on equipment but the bosses said they were too expensive. OK, I'll replace stuff when it breaks, not my wallet.

One last piece of advice and then I'll go away. Runaway engine. Trust your Emergency Shutoff ? I don't . It is there as a manual back-up (military redundancy ?) in case the electrical fuel cut-off doesn't work. A runaway (see the big locomotive above) is not running on it's normal fuel supply. Somehow, (often the turbo, sometimes the breather system) engine oil has become the "fuel" and there is no way to control it or shut it off. You then have two options. Run away and wait for the Big Bang, or, cut off the air to the engine. Some Detroits have an air cut door as their emergency shut down. It works, I've had to use it. For those not running Detroits with this feature, do you have a CO2 extinguisher in your kit ? You should. I recommend a 20 lb. version. It works on electrical and flammable liquid fires. Guess what a runaway is. A flammable liquid fire, inside a tube. Emptying a 20 lb. CO2 into the air filter intake will probably kill the runaway. No promises, I have seen that Murphy bastid too many times, but it's your best bet. Worst case, it doesn't work and so you go back to option one. Run away from the runaway.

I offer these tips in the hope that they will save someone from sitting beside the road or in their driveway when they want to be out enjoying their vehicle. Best wishes to all and Happy Motoring !

 

[WillWagner]

I forgot about this, I have a boat load more pics. Leme see if I can dig some up.

 

[Trailboss]

My contribution:

Dropped a valve in the #3 cylinder in a M818 that destroyed 2 pistons. Happened during a recovery of an empty M871 trailer and I had driven about 245 miles of the 355 mile round trip. See post #59 for photos:
http://www.steelsoldiers.com/showthread.php?41716-Recovery-disaster-Long/page6

As I later said, I was worried that I broke it, but the mechanic said sometimes things just break. He said oil flow was good, and there was no signs of over-revving. Maybe something was not done right, or there was a minor stress crack when the engine was rebuilt by the military 1150 miles previously, and the valve just let go. I never drove it over 2100 rpm for the 900-1000 miles I put on..

 

[WillWagner]

Here are a couple of bottom end failures, 1st one is a 2016 QSB4.5 that was ran low/out of oil.