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By Moz - 18 Years Ago
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greetings guys from geelong victoria australia my name is moz i have what we call in oz a 58 customline & a 59 mainline ute (ranchero) my question is have you ever heard of anyone breaking a crankshaft ? thanks moz
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By LON - 18 Years Ago
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Hey Moz , Welcome to the site . Great to see a few more Aussies joining in .Yes, Y-block cranks do break ?? Just arrived home from "Wintersun " on the Gold Coast .Had around 2000 cars there,unfortunately only around a dozen Y motors .Only spotted 1 mainline "UTE ". Regards Lon
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By Glen Henderson - 18 Years Ago
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Welcome to the site. I bought a junk yard engine a couple of years ago that had a broken crank and the number four main cap was broken. The old gentleman that I got it from had pulled it from a F600 that was used to haul pulpwood. He said that the engine was still running when he removed it, just knocking a bit. I still have the block, I replaced the main cap with one from an engine that had frozen and cracked. It will need to be aligned bored, but other than that it looks good.
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By pcmenten - 18 Years Ago
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I bought a 312 that was supposedly a running engine. Upon teardown and inspection, the crank was cracked on the rear rod throw. I eventually discovered that the bolts used on the rear cap were too long; they would bottom out. I'm pretty sure the reason the crank went bad was that the rear cap was loose and the poor crank was rattling around on that loose cap.
Obviously, you've got to make sure you use the right bolts in the right caps. They don't all interchange. I 'fixed' the problem by grinding a bit of the bolt's end off. I suppose I could have put lock washers under those bolts, but I tend to follow factory design when I can.
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By Hoosier Hurricane - 18 Years Ago
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I once broke a 312 crank on the dragstrip at 6000 rpm. When I pulled the pan, most of the crank was in the pan, along with the 3 center main webs. The crank was in 9 pieces. I did save the cam, heads, and intake manifold. I also was once given a '59 292 with a broken crank, broke right in front of the center main journal. But the largest majority of Y Blocks live out their lives without breaking a crank. John
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By Moz - 18 Years Ago
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thanks guys my 272 was rebuilt by an unknown person who must have forgoten to do up #3 & 4 mains #4 came loose and bang right through the big end journal thankfully i just had to put another crank in & of i went no other damage
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By pegleg - 18 Years Ago
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John didn't mention that the blower cars do break the cranks in front of the first main. We think it's belt tension from the blower. He basically solved the problem on the Hurricane with a Fluid-Damper type installation. But understand, the motor in the Hurricane spend a LOT of time at or close to 6000 rpm. It makes well over 400 hp, and I mean well. It's pulled the 3800 lbs of Feistritzer and Ford to 119 mph quarter miles. Also note that the 312's had larger mains, but the same size snout as the 272 & 292's.
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By mongo - 18 Years Ago
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the snouts on 312's break off , had 57 f500 ,just break off, along with everything else, just dropped on the ground. Talked to the circle track racers in the Day , they broke em the same way
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By DANIEL TINDER - 18 Years Ago
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I wonder if dampner failure (when the doughnut slips back and hits the motor mount/timing cover) is usually what causes the crank snout to snap off?
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By PF Arcand - 18 Years Ago
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Another reason for some 312 crank failures was unfortunately caused by an error in Ford's specs in early 1956. The Torque spec on the Main Caps was too high ( I won't repeat it here or it will be accidently used again!) This resulted in stripped main bolt threads, or cracks in the block between the bearing seat area & the bolts. Also, some rebuilders would overtighten the main bolts, with the same result. As I understand it, the "absolute max" on main bolts is 105 lbs. Street Rodder's series on the engine, a few ago, recommended 90 lbs max.
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By Moz - 18 Years Ago
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yeah i know about the torque problem they also had the problem of mixing up the mains bolts some are shorter if you get them wrong they either bottom out or they will also crack the webs
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By 46yblock - 18 Years Ago
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DANIEL TINDER (6/15/2007)
I wonder if dampner failure (when the doughnut slips back and hits the motor mount/timing cover) is usually what causes the crank snout to snap off?Seems plausible to me. I tore down a junkyard C2AE that had that exact problem. The damper had failed, slipped back and sheared off one of the heads of the cover mounting bolt. Also took a chunk out of the keyway, but in this instance didnt break the snout.
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