Thrown Rod on Isuzu Trooper

I tried inquring about this at the one Usenet Isuzu newsgroup but am not getting any feedback.
Friends of mine have a 2000, 3.5 Liter, 4-wheel drive,
automatic transmission, Isuzu Trooper. While driving it up a large hill (really, the foothills of a serious Western mountain range), the car stopped running. I don't have the details on this, but subsequently, they had it towed to a nearby mechanic who works on Isuzus and he said it had thrown a rod. The car is currently sitting in the lot of another friend who has some background in auto/truck mechanics but has not yet had a chance to look at it. I am going to look under the hood sometime in the near future and try to verify the thrown rod and destruction of the engine. The owner said he was a bit remiss about oil changes but did have them done every 10k miles or one year at least. Some questions:
-- From my googling, a thrown rod can be very obvious: A steel rod pushes through the crankcase or engine block. Can it also be not so obvious? E.g. suppose the rod has disconnected from the piston head, and it's just banging around inside the cylinder. The latter scenario presumes the vehicle was stopped quickly. What else can I look for? I am not sure I will be able to try to start it up yet.
-- I have been making online inquiries of salvage yards about (1) used cylinder blocks; (2) used, entire engines. Dumb question but I'm not quite clear on this point: Does it matter whether the used engine was attached to a 2WD Isuzu Trooper? It seems both 2WD and 4WD Troopers, of the same 3.5 Liter engine displacement, are available.
-- I am getting quotes back in the $3k-$4k range but from yards many states away. Shipping seems pretty reasonable and common. Has anyone purchased an engine or cylinder block from several states away? What kind of assurances can I get about the condition of the engine? One seller so far has said he has a CarFax report verifying the engine has only seen 32k miles. I plan to check locally, too.
-- Evidently going up hills in too high a gear can throw a rod. The high gear translates to low revs but high torque, stressing, from what I understand, the piston rod, crankshaft, and associated bearings. Can anyone elaborate further on this? It might help me to identify whether a rod was actually thrown.
-- I understand installing a new engine is around a day's work, maybe less. This so? I am going to try to get a quote for the labor from my favorite import shop in mind but will also inquire at the nearest Isuzu dealer. Anything in particular I should ask them other than: "How much to remove an old engine and install a second-hand one?"
The owners of this car do an astonishing amount of volunteer work in animal rescue. They are down to one truck (while normally having two). Given the circumstances, your assistance is especially appreciated.
(Honda note: Isuzu has done some business on the trucking side with Honda.)
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Put the car in neutral, and find some way of turning the engine over by hand. If there is a thrown rod or a dropped valve, then you shouldn't be able to turn it 360, without hitting some sort of obstruction. Sometimes a thrown rod will knock a hole in the side of the block, but not always. Sometimes the big end comes loose and pretzels itself, while the piston drops into the rotating crankshaft. Sometimes the little end comes loose instead. Whatever it is, the engine won't "feel right" while you are trying to turn it over. If you have a compression gauge and the starter works, you could try that too. An engine with serious internal damage will give very strange compression test results.
Usually, a thrown rod is a sign to discard the engine, or at least the short block. A dropped valve can produce similar symptoms, and usually means you need a new cylinder head. If you are into restoration of antique vehicles, then maybe you would attempt a repair like that, but not on a six year old car.
The "too high a gear" theory has some merit, but not with an automatic transmission. The auto should have shifted into a lower, more appropriate, gear. Driving for very long at too high rpms can spin a bearing though. That could have thrown a rod or seized up the crank.
Although I generally "push" my oil change intervals, I do feel that 10k miles is too much for a passenger car, most of my driving is highway with full warmup of the engine before I stop, and I use high quality, high price oil filters. (I have to go 50 miles to get groceries.)
The best place to find out about parts interchangeability, is from a recycling yard. They have manuals of what fits into what, that are generally very accurate. Do not assume that all 3.5 liter engines are the same.
Earle

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Earle Horton wrote:

Are these a Isuzu engine or rather the Buick V6 that went into some of them?
May be better to dump it to someone who wants to do an engine swap.
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Earle, wow, this strikes me as a fabulously informative post. I will explore all you said as my access to the truck allows. I won't be doing any of the restoring myself; this is for my education and hopefully to provide these folks with some assistance. Thank you.

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Elle wrote:

when it throws, it usually throws violently, i.e. through something. if you can see the engine clearly, that should be detectable. if the motor runs and ejection is not obvious, look for other clues like a mysterious "misfire". i once had a vehicle come in with "a strange oil leak". the guys said: "every time we fill with oil, it disappears again. it's leaking out somewhere, but we can't see where. oh, and it's got a slight misfire." it sure did, it was running on 5 cylinders with the 6th thrown out into the engine bay.

what about jdm imports?

not on its own.

"lugging" [too low revs] can cause fatigue which will throw a rod when a cap bolt fails, but over-revving will do the job just as effectively and is much more common. or it's just a substandard cap bolt. lugging is most unlikely if the vehicle's automatic.

yes.
basically.
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Elle wrote:

-------------------------------------------
Yes,
IF you have air tools, a hoist, maybe a crane, and any 'special' tools the MAKER dreamed up for holding their engine in place. Otherwise you spend half a day driving around town trying to find some %#*!#@ left-handed needle-nose *&%#$! thingy that holds the _____________ on.
Keep that in mind. :-)
'Curly'
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I will double check that the shop that the owners of this Isuzu Trooper truck use are well-prepared to do an engine swap, if it comes to this.
I was mostly curious as to how long it might be before the owners get the truck back.
I wish I could get my hands on the changeout part a little, but I hesitate to do even minor work on other people's cars (too much liability, emotional and financial). Plus, as you suggest, I have nothing like the special tools that are needed. Those little hoists/cranes that lift the engines out look like fun. Such "possibility."
One interesting thing I learned from the several engine salvage yards that responded to my query is that many list on their web sites the cost of a refurbished 91 Civic (my car) engine. It's typically around only $600, including various warranties. At least, $600 seems cheap to me.
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Bad mojo! I have only seen two thrown rods personally, and both times the rod came through the crankcase but was not sticking out. I don't think that's always true. In both cases (a Subaru and a Toyota) the engine was pretty worn and had known oil pressure problems that were not worth tracking down in so old a car. In each of those the diagnosis wasn't hard because there were pieces of crankcase on the ground under the engine, which seemed somewhat irregular....
One caveat on the engine swap - don't forget to address the problem of dealing with the refrigerant if the vehicle has A/C. Maybe the compressor will swing out of the way and the hoses won't be threaded through anything important, but when was the last time you were so lucky?
Mike
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Indeed!
This 2000 Isuzu truck has "only" 133k miles on it. But maybe this is a lot for Isuzus.
These folks may have done some serious towing with it, wearing bearings prior to this apparent catastrophe. (Sorry I can't get all the facts just yet.)

I'm not going to attempt this myself. I wanted to know on what to keep an eye with any shop that does the job.
Thanks for the input, Michael.
I'll update if I or someone else ever gets access to the truck.
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