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There was indeed an oil starvation problem on the LH side, and here's how I think it went:
Both sides oil tube fittings were replaced at 95K. There is no question that they were installed correctly, down all the way. Later, the rearmost bearing became clogged. This heated the bearing up to the point where the oil tube fitting melted and no longer sent even a trickle of oil to the other bearings, and the same thing happened to those. I found bits of material in the bearing oil passageway. Both sides tubes were removed again, new fittings installed after the tubes were cleaned to to a mirror-like shine internally.
Since then (after new LH cam and bearings), the problem hasn't returned. But I didn't change the chain, etc after all that abuse, which I should have done.
I agree with your thinking on the push-pull effect, because you can see this effect when you spin the engine slowly by hand. A bad combination of RPM, load, and acceleration / deceleration could cause a harmonic enough to break the guide. I've installed two metal guides on the LH side so that should be that, I hope! Nonetheless, I'm going to be inspecting things every oil change from here on out for premature stretch.
This is not going to be one of those "250K motors", but I'm hoping I can get another 60 or 70 out of it before I have to do the heads, and at that time I'll assess the whole thing.
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