Blown Engine, And How!

[Redbarnresto]

Thought you guys might like to see this. This engine came out of a Bus a customer of mine bought. He never saw it running. We were hoping it'd be a perfectly good little engine, but were prepared for the worst. We sure got it!

The engine would spin back and forth but not 360 degrees. It'd spin maybe 330 degrees one way or another and then smack into something. I pulled the valve covers off and noticed that none of the valves open and close at all, they were all just dead level with each other and wouldn't move. I knew that could mean only one thing.

I started tearing the engine apart and found #4 rod up through the case, which the fan shroud was hiding.

Here's what's left of #4 connecting rod. Both nuts are still on!

Damage to the crank.

The camshaft, or should I say camshafts?

The entire case is filled with this stuff.

This is interesting. All the intake valves are black except that one that was on #4.

Not sure what happened first that caused all this, but I'm sure some of you will have theories. The oil was very low (though it could have been sitting for years and dripped out), and there was also no front engine tin which would have made the engine run hotter than usual. There was one of the six main case nuts missing, and some of the others were loose.

Definitely the worst failure I've seen!

Dan
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Red Barn Restorations

[Bashr52]

That is intersting that it was the #4 that let go. If it was the #3 it would be more understandable.....

[HRVW]

Picture was NO big deal for me as I've seen loads of them during my engine building yrs....comes with the territory.

One part fails or lack of oil and KABOOM.

[[email protected]]

Thank you for a perfect picture of what I always tell people. Stock connecting rod bolts DO NOT BREAK. The rod itself will come apart before the bolt will.

Sorry about the engine though

[vugbug68]

spun rod bearing, rod got too hot and bam. Heads actually look pretty good
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71 Super - Backroad Thrasher
66 Corvair - Weekend Cruiser
90 4 Runner - Muddin

[JoeD]

Yes spun rod bearing. Obvious in the photo. It burnt pretty badly.

[modok]

#4 is the most common rod bearing to go out first. i don't know why, we'll probably never know exactly what started this one to go either, all the incriminating evidence has destroyed itself

Of course, it was probably just low oil pressure.

[SamT]

I love tearing into exploded engines, as long as they are someone else's. That looks like it was in an engine blow contest, about par for my experience with bus engines especially type 3.

[75smith]

[vugbug68]

#1 bearing is the one i've seen spun the most.
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71 Super - Backroad Thrasher
66 Corvair - Weekend Cruiser
90 4 Runner - Muddin

[modok]

Maybe it depends what caused it?

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