Opinions on why this engine failed?

[tscompusa]

I am curious on opinions on what would make a rod come out of the block and be in this condition still? The wrist pin area did not break, and the big end completely tore apart.

Do you guys feel this is a rod bolt stretch issue or did the wrist pin come out of the piston prematurely due to a bad circlip seat or something of that nature?

Or is it reaching just to assume we can somewhat diagnose the issue before digging into the engine fully?

Picture of rod below:



The big end looks like it got very hot also.

[Newold1]

Took a lot of heat to discolor that rod with those lousy colors.
That big end froze up on the bearing and crankshaft rod journal and was ripped from the crankshaft and the rest is now history.

Take the engine down and you should be able to identify the failure cause fromthe look of other bearings and parts.

Sorry for your loss!

[tscompusa]

Took a lot of heat to discolor that rod with those lousy colors.
That big end froze up on the bearing and crankshaft rod journal and was ripped from the crankshaft and the rest is now history.

Take the engine down and you should be able to identify the failure cause fromthe look of other bearings and parts.

Sorry for your loss!

Thanks for your response. This wasn't my engine, but we are trying to determine the cause of failure.

So if the rest of the rod bearings look good you suggest maybe someone didn't properly install the rod bolts/cap that failed?

I think that would make sense. I will update once we get the engine in our possession and tear it down.

Thanks again.

[Newold1]

Sorry, no that is not exactly what I was pointing to. If the rod bolts or cap just failed the high heating colors around the big end of the rod would not be there as it just would have failed and destroyed things in the cylinder and the engine.

What I am leaning towards is either there was a very bad fitment of bearing to journal ( clearances way to tight) potentially causing a seized or spun bearing condition that with continued use froze up with heat on the rod journal or an oiling issue at that bearing and journal and possibly others which ultimately produced the same seized condition.

Looking at the other bearings on other journals will most likely show whether it was an oil issue or clearance issue.

Please post pics of the other rods, bearings and the crankshaft rod journals here on this post if you can so we can all learn and comment on possible causes.

[tenxal]

Started at the bearing/journal and escalated from there.

[JoePorting]

Lack of oil. Why the lack of oil at that rod is the real story.

[tscompusa]

Ok. Thanks guys I will update with pics of the other 3 remainder rod bearings once we pick up the car from the customer and tear it back down.

[modok]

First it melted the bearing, THEN it threw the rod out.

If a bolt fails you will often find the bearings still in recognizable shape save for a few dings, but I think your bearings(if you do find them) will mostly be steel shrapnel.

[Frankshaft]

The rod bearing started going away for any number of reasons, it spun, chewed the bearing till there was huge clearance, and no oil, then, the big end was slide hammered until the rod bolts were stretched out and couldn't hold on any longer, and at some point it was banging off a whole bunch of stuff, and broke.

I gaurentee, it gave you some warning signs that you ignored, and could have prevented this. Popping in high gear, big drops in et, loss of power, missing and shaking, not responding to any tuning change etc.

[Schurkey]

I had a Honda Civic that let go similar to that. Big end of #3 burnt black, bearing spun and worn to nothing, all the mains and all the other rods looked beautiful. Appeared to be a one-rod oil failure. I couldn't explain it then...or now.

58,000 miles. Steady ~70 mph in 5th gear, February late evening, temp around zero. Cardboard on the radiator to make the heater work--temp indication good, oil pressure good. Driving along...KBANG! Blew a chunk out of the block at the oil filter.

To this day, it's the only connecting rod I've held in my hands that broke into (4) pieces, but still had both rod bolts INTACT. The rod itself went missing, but I have a hateful out-of-focus Polaroid photo that got too close to grinding sparks and is itself damaged.

[dwilliams]

Judging by the picture, I'm going to say insufficient side clearance, possibly from a bent rod or by having the big end machined or honed crooked.

I've found a few rods that were dead nuts on big end ID, but leaned off to the side on my straightness checker.

Also, just because the rod gauge shows the bore is round and to side, it doesn't mean that the bore is the same size on the edges as it is in the middle where the pins ride. I've seen some rods with a sort of barrel shape, with the insides larger than the edges. I think that comes from short-stroking them on the hone and wearing the stones funny; at least I've seen some stones worn like that.

[Frankshaft]

^^^^^ no, read my reply, that's what happened. End of story.

[user-17438]

The rod bearing started going away for any number of reasons, it spun, chewed the bearing till there was huge clearance, and no oil, then, the big end was slide hammered until the rod bolts were stretched out and couldn't hold on any longer, and at some point it was banging off a whole bunch of stuff, and broke.

I gaurentee, it gave you some warning signs that you ignored, and could have prevented this. Popping in high gear, big drops in et, loss of power, missing and shaking, not responding to any tuning change etc.

.
You couldnt be any more incorrect. This is a clear sign someone put sugar in your gas tank.