My crank broke on my rebuilt engine, and got into the block blowing a nice hole in it as well as bashing the oil pan and tearing it a bit. Was doing about 75mph at 3500rpm and it went ka-boom in the hammer lane....and before I could ease over and kill it, it did it itself. Anybody happen to have one? I can pay with paypal right away. I lucked out and found a rebuilt in the crate slant for $300 on craigslist, same era as what I had, .040" over that was rebuilt by an outfit called Sun Engines out of Texas. Nice looking engine, everything looks good and I'm in the process of cleaning and checking everything before swapping my head, cam, etc. Just need a pan. Thanks

What year/body style?

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Official Cookie and Mater Tormentor.

67 A100 center sump.

Hi speedy.
See if you can use this oil pan form silver-seal.com. Only $41.20.

Olaf.

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Aspenized

I have no A-100 stuff anymore.

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Official Cookie and Mater Tormentor.

Looks the same, just ordered it, hope they have one in stock! I thought it was gonna be more complicated than that! Thanks A Bunch

Looks like a nuke went off inside the crankcase lol breaking stuff sucks but it makes for cool pictures

Kev

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Yeah, while it's depressing to blow a motor...... ...... I still found time to take a "creative" photo of the destruction......

Who rebuilt the motor? That is a pretty severe failure for a rebuilt motor. If you had a shop do it I would take motor back to them and ask some pointed questions about a refund.

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Casually looking for a Clifford hyperpak intake for cheap.

While I would love to have them cover it, I'm not in a position to wait for however long the whole process will take (longer than I have time to) to get it replaced through them. This was a 50/50 or less deal (they only bored, decked, and assembled the reciprocating assembly using my 300,000+ miles crank and rods in a replacement block with new pistons) and rebuilt the head. I assembled the rest. The crank broke and I made it worse (as bad as it looks) trying to get off the road. There's no signs of abuse, incorrect timing, piston scoring, fueling leaness etc. Being I scored a replacement for cheap, I'll count my blessings and eat the couple extra hundred bucks and try try again.

so from a rebuilding point of view,,,
what engine assembly or component matching errors can result in crank breaking at cruising speed,,,

I am guessing but from a component matching point,, the wrong damper or flywheel balance,,,could result in a broke crank,,,
Don't know what one could do as an assembly error to cause this...


any other ideas?

If the oil pump and cam were relplaced I would make sure the pump gear didn't fail

I can remember an instance waaaaay back in about 1965, where a friend of mine crashed his 6 cylinder Holden ( an Australian GM product).into a tree.
Not a particularly severe accident, but the body was a wreck. Engine appeared fine, and it took no direct hit.
To cut a long story short, that engine was transferred into another car, fired up, and ran about an hour before the crank broke.
The sudden stop in the accident must have stressed things more than it could bear.
Had your engine ever had a trauma like that?
If you can, can you post up some more pics of the internals, showing bearings and bore?
Something must have caused it.


regards,Rod

I don't know, but assessing everything in no particular order, the cam looks fine, really nice wear patterns, no unusual wear, lifters look good, pistons look good...other than the #4 piston having some signs of abnormal wear on the skirt from the crank breaking/bending and running up and down the bore cocked.
The engine is out, the head is off, the cam is out, #3 and #4 piston/rod assembly is out and there is nothing that looks out of the ordinary. The bearings look good, no abnormal wear. No signs of detonation or any wear that would signify too much heat. From everything I can see, it looks like the crank just said I've "had enough" and broke. :shrug:

cranks don't "just break",, without some kind of secondary cause,, like a balance issue,, or if it was dropped,, bent excessively then straightened,, that process could cause a fracture that lead to failure, more so with a cast crank than a steel one. anyway there is a reason. Maybe if you put together a new post,, labled broke crank with photos of the broke cross section,,, there would be discussion around that.