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Obviously it has something to do with the connecting rods, but what I don't know. Broken wrist pin? Tore up bearings? Broken rod bolts? I've heard the term before but I have always suspected the people who look at your tore up engine and say "it probably threw a rod" are simply repeating jargon they've heard from others in the past, and I want to know what it means before I do the same thing ;)

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Usually the big end of the rod comes loose. If it perches just right in the crank case the crank can come around and smack it through the block wall. John

It would be a shame to have passed the test but to have missed the lesson.
 

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I'm not an expert, but at it's worst throwing a rod means you now have a hole in your block where the rod exited at extremely high velocity.

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The big end of the rod meaning the crank mounting area of the rod, or the wristpin area (part connected to the piston)? The bigger end is the part that connects to the crank, so you're saying the bolts have broken/nuts come off and if the rod's hanging low in the cylinder the crank journal can whack it & send it through the pan? I would think it would have to tear the hell out of the cylinder wall first...

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One time I was getting on the freeway at WOT (on a motorcycle) I heard a load pop and was suddenly enveloped in smoke. When I got the bike home I noticed a fist size hole through the crankcase. I think that is what "threw a rod" means...and I also think I learned to determine a lifter tick from a rod knock from that little experience. Maybe that's why the bike was given to me:)
 
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threw a rod=deep sh** lol

~Chris
San Antonio, Tx
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70 fastback done by may/graduation...hopefully
 

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If the piston is high in the cylinder then little of the rod may hang out but if it is low..... If you wipe a bearing or spin the bearing then it will start to knock and the knocking will eventually fatigue the metal and cause it to fail at its weakest point. The rod cap bolts often break or the cap can break. John

It would be a shame to have passed the test but to have missed the lesson.
 
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All true !!! Gentlemen refer to this condition as "traumatic disassembly".

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Ok guys... Here are the facts..
When you have an old engine, espically one that is using oil, and it goes low, you tend to develope knocks.. The knock is a sound emitted from the upper part of the connecting rod slapping the pinon the crankshaft...

There is no knock in a normal engine due to the fact that the impact of combustion is "absored" by the thin layer of oil between the bearing and the rod/crankshaft.
When and engines tolerances between the bearings and rods begin to open, the oil pressure drops, thus inducing wear on the fragile bearings (inserts)..
When the inserts start wearing thin, oil pressure is at an all time low and a knock is heard

When the oil pressure becomes low enough the bearing and rod begin to fuse themselves together, and with the rotating motion of the crankshaft, the bearing spins (knocks the tabs off and rotates)

After spinning, no oil gets to this journal and it's not far from destruction.. Keep driving and the rod/crank sieze together.. You figure the rest.. Can't make it rotate anymore and something has to give - usually the rod that is tossed through the oil pan (if lucky) or through the side of the block...
This my friends is thefacts of a spun bearing, thrown rod and a rod knock.....

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That's call " throwing a leg out of bed."!!!!!

Not nice~

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I have the PERFECT picture if I can find it.... A few years ago
entering a turn a car in front of my '72 Skylark (Dirt Oval)
broke a driveshaft! And it wedged between my oilpan and
the ground and ALL the oil poured out. All I knew was the
tach said 7 grand the oil pressure dropped below 5psi and
BAM! I've never saw more rods come out of a block to be
exact it was 3. Not to mention all the broken pieces of piston
laying on the crossmember! To all (newbies) piston and crossmember should never come together. <G>

460Stang

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When I "threw a rod" in my '68 Cougar, the rod bolts snapped and as the rod "threw" out of place, it went through the side of the oil pan. Then the crank comes back around and slams it back up at a really now wierd angle shattering the piston and shoving the rest of the rod through the cylinder wall. In a matter of 3 seconds my engine was transformed from a finely tuned machine to scrap metal. *LOL*

That's how I define "throwing a rod" /forums/images/icons/smile.gif

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I have seen a Camaro at our local drag strip throw a rod. wrecked the motor, they figured they broke a rod bolt. I also bought a Ford pickup from a guy who had a 302 with Performer cam and intake in it. The retainer on a valve let go and sucked a valve. Nothing on it was any good except one head. You have to have good rod bolts and retainers and locks on any performance engine.
 

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I think in some parts of the world I've heard it is a form of horse shoe throwing,,,hehehe,,but I'd bet "throwing a rod" and trying to hook the crank journal end on a horse shoe post 30 feet away would be TOUGH,,,LOL anybody want to start a new sport How about catching the wristpin journal on the post Whewww

Robbie "Keep trying,,,What have you got to lose"
67 GT 500
70 Boss 2
 
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