I have a engine that let go after 45,000 miles, and can't figure out what happened, so before I build another one, I like to talk to a good shop that is really good at diagnosing
stuff like this. The only parts reused were the block, crank, and rods, everything else was new.

more info: what eng. what parts. how did it let go (RPM) WOT (I am assuming). You might tear it down yourself & take pics or just post what you see.

Lets see some pics. Usually can be figured it out.
Doug

OK, let me give a short run down, and pictures later if I can load them. It's a Neon 2.0 sohc, I wanted a stock rebuild, so I get a Mahle engine kit with cast pistons, and clevite bearings. The crank was polished, and they said it wasn't really egg shaped. So, I only reused the block, rods, and crank. New rod bolts were used. even the head was a nos head, with all of the cam, and rockers and assorted parts new. A Melling oil pump came with the engine kit, standard volume. The engine was primed with a pressure pot, and showed 80 psi when first started. I broken it in with Gibbs break in oil for 800 miles, then Mobil 1. Now, I drive it for 45,000 miles with no problem, and the wife drives it to work one day, she was going 60/70 mph on the interstate, so around 2500 rpm, when it lets go. One rod spun a bearing, got hot, and broke coming through the block, and another rod was bent. After looking at every thing I can't find a reason why this should have happened. The bearings look like they were oil starved, but the crank, except for the broken rod look just fine. I'm building another engine, and want to avoid whatever happened.

Was it fairly low on oil? 45,000 is a bit of miles for an issue to creep up out of nowhere.

It used less than a qt of oil in 10,000 miles, and only had 4,000 since the last oil change. The oil pump didn't have any junk inside of it, nor did any oil passages in the bottom end, including the crank.

I broke a motor one day, just out cruising around enjoying the day, probably not more then 2,000 rpm all day.
I was pretty stumped until I remembered what I was doing with the car the night before....I probably really broke it the night before, but because of the easy cruising, it didn't show up right away.

If your wife drives like mine does, I wouldn't have been surprised if my wife wouldn't have just smoked someone on the interstate that she though need a lesson learned. Also, are you sure she was in high gear? 60-70 in 2nd or 3rd is a lot different then 60 -70 in 5th or OD on an auto.

Could have had an oil pump seize up too. That will kill them pretty fast. Gene

She had in 5th, and the way a Neon oil pump is made, I don't think that was it. The inner gear of the pump is driven directly off of the crank, and it doesn't have any signs of seizing. The engine had plenty of oil, cause oil was pumped out every where after the rod went through the block, it even set the oil on fire burning up the engine harness.

Which rod, #1 or #4 ?

Oil pump on them feeds #1 first then goes rearward I believe ( been a while since Ive been in one )

All the bearings hurt or just the rods ?
No signs of a broken or stretched rod bolt I assume ?

Thats one engine that's far from a known problem child with the bottom end.
I honestly cant remember ever having any issues with a 2.0 ( other than oil leaks )

Number 4 broke, and one of the others was bent kind of like it hydrolytic. All the rod bolts were new. Number 4, the bolts broke when the rod came apart. I'll take pictures as soon as I can.

How about the belt? Could it have skipped the belt and hit the valves causing the rod failures? Is this a clearance motor?

I won't know that till I take the head apart, usually that just bends the valves. That is sone thing to check. But the bottom of #4 was black from heat.

I don't think I would rebuild that eng.again I would find a good used one to start with Neon SOHC engines are plentiful & cheep.I have 3 Neon's all bought with low miles & cheep,last one I bought only has 29k on it & I paid $800 clean mint grandmothers car.
https://newjersey.craigslist.org/cto/6310007803.html This one is over priced but there out there.

I'm not gonna rebuild it again with two holes in the block, it even put holes in the pan. I have another block, and crank.

Some pictures

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