Low oil caused rod bearing noise - opinons saught

[LoveLearn]

I recently bought a clean 1990 Camry with 4-cylinder 2-liter 3SFE engine and automatic knowing that it had just developed a rod bearing knock. The student who owned it failed to check its oil level until an engine knock started. He immediately pulled to the road side and called his father on his cell phone. Dad came with oil to refill it right there without restarting it. They were disappointed that refilling with oil did not stop the bearing knock. The father instructed the son to slowly drive it roughly 1/3 mile to an automotive repair shop parking lot. They got estimates, son needed to get to classes right away so they bought another car. The shop wanted a LOT of money and said they'd only be willing to replace the engine. So they advertised it and I bought it from that parking lot, loaded it on my trailer where it awaits my next step.

Now, I'm eager to hear opinions, but only from those who have rebuilt or repaired the bottom ends of Toyota engines. Since I rebuilt my first engine over 40 years ago, I don't need speculations by racing parts swappers who have no experience with how Toyotal engine bottom ends typically fail. Cranks are harder than bearings by design. Some cranks seem very tough and aren't quickly damaged by most onset rod bearing failures. Some other brands seem so fagile that moments after any rod bearing develops enough clearance to knock, their journal diameters are knocked out of round so they must be reground one size smaller. If Toyota 3SFE cranks are as tough and durable as old Volvo 4-cylinder cranks, I can probably (no gurantee) restore this engine to daily driver service by just replacing its rod bearings. Wrist pin - piston failure is HIGHLY unlikely. Similarly, main bearing failure is very unlikely since the sound is reportedly periodic like a rod bearing with too much clearance. Has failure experience shown these cranks to be tough or comparatively fragile?

So what do you fellows think are the chances that replacing these rod bearings will correct its bearing problem? I see low mileage used 3SFE engines from Japan on eBay as well as lots of full parts donor cars offered. Swapping in another engine appears to be my much more expensive alternative to just replacing the rod bearings.

Question 1: If you were guessing chances of satisfactory result from just replacing the rod bearings, would you guess it to be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% favorable?

Question 2: Which approach would you take, replace bearings and see if that corrects the problem or swap in a replacement engine? Why? If replacing the entire engine, would you go for one of those "low mileage engines from Japan" or a cheaper engine with perhaps 100K to 130K miles from a US driven Camry or Celica?

Thanks for your consideration,
John

[Bmaintz]

I would drop the oil pan & pull off the lower cap on each rod one at a time for inspection.... If it wiped out the rod bearing & not the journel then a new bearing caps will do the job, make sure you use plasti guage to get the right size bearing inserts.... I would also check your main bearing one at a time, & while you are at it check your cam bearings fir scaring... Bob