Posted: 4/7/2004 1:28:18 PM EDT
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Check out this engine http://www.bath.ac.uk/~ccsshb/12cyl/ |
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funny you should mention wrenches for torqueing the bolts. for about a year i ran a catapillar 3612 engine generator set that burned landfill gas. that engines' head bolts were torqued to 5400 foot pounds,and each of the heads was seperate instead of one long one. i say head bolt, but they are really studs with nuts. cat has a hydraulic tool that threads onto the studs and has a wall with window slots that goes around the nuts. this hydraulic tool actually is comprised of 4 pistons and the frame, one piston for each stud. 5400 pounds of hydraulic pressure was applied to each piston at the same time and the studs would be stretched. once stretched, a small bar was inserted through the windows and into holes drilled into the flats of the head bolt nuts themselves. the cat tech would simply turn the nuts a little at a time untill he had backed them off a few turns. once that was done, the hydraulic pressure was removed, the studs returned to their normal length, and the tool was removed. once the tool was off, the nuts would spin off by hand and we'd bring the crane over to yank the head off. metal can be stretched, and unless it's elastic limit is exceeded, it will return to it's origional shape. to put the thing back on, simply drop on the head, spin the nuts on hand tight, apply the tool, stretch the studs,retighten the nuts to hand tight, remove the hydraulic tool and the studs suck back down to that 5400 pounds. 1st time i was told they torque by stud stretching, i said bullshit. i just didn't know, but they actually do that. not to say that this engine is done that way, but i thought it was cool enough to throw out there. |
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Quoted: funny you should mention wrenches for torqueing the bolts. for about a year i ran a catapillar 3612 engine generator set that burned landfill gas. that engines' head bolts were torqued to 5400 foot pounds,and each of the heads was seperate instead of one long one. i say head bolt, but they are really studs with nuts. cat has a hydraulic tool that threads onto the studs and has a wall with window slots that goes around the nuts. this hydraulic tool actually is comprised of 4 pistons and the frame, one piston for each stud. 5400 pounds of hydraulic pressure was applied to each piston at the same time and the studs would be stretched. once stretched, a small bar was inserted through the windows and into holes drilled into the flats of the head bolt nuts themselves. the cat tech would simply turn the nuts a little at a time untill he had backed them off a few turns. once that was done, the hydraulic pressure was removed, the studs returned to their normal length, and the tool was removed. once the tool was off, the nuts would spin off by hand and we'd bring the crane over to yank the head off. metal can be stretched, and unless it's elastic limit is exceeded, it will return to it's origional shape. to put the thing back on, simply drop on the head, spin the nuts on hand tight, apply the tool, stretch the studs,retighten the nuts to hand tight, remove the hydraulic tool and the studs suck back down to that 5400 pounds. 1st time i was told they torque by stud stretching, i said bullshit. i just didn't know, but they actually do that. not to say that this engine is done that way, but i thought it was cool enough to throw out there. That's neat. You learn something new every day. |
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Quoted: 1st time i was told they torque by stud stretching, i said bullshit. i just didn't know, but they actually do that. not to say that this engine is done that way, but i thought it was cool enough to throw out there. |
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I'd guess that's achieved by a planer that runs over the block on the crane rail system, or a similar system. It'd be a BIG planer, but in this case, it'd be much smaller than the workpiece. I am referring to a planer in the metalworking sense, not the woodworker's tool. A planer like this is intended for face milling and the cutter heads may be two feet in diameter, with replaceable inserted cutting teeth. The planer would probably have several such cutter heads on it. CJ |
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Quoted: I'd guess that's achieved by a planer that runs over the block on the crane rail system, or a similar system. It'd be a BIG planer, but in this case, it'd be much smaller than the workpiece. I am referring to a planer in the metalworking sense, not the woodworker's tool. A planer like this is intended for face milling and the cutter heads may be two feet in diameter, with replaceable inserted cutting teeth. The planer would probably have several such cutter heads on it. CJ Yeah, we have 6 of them at the rocket ranch. They have a bed that is 40+ feet long by about 14' wide. If I can figure out how to post a pic, I'll try later. |
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Quoted: Quoted: I build vehicles with three 15,000,000 hp engines on them . Of course they run on liquid hydrogen and liquid oxygen. Talk about Sally Soccermom getting Skippy and Buffy to school on time! Someone's referring to the SSME.... Nope, my bucks are on the Delta IV plant in Decatur, Alabamer. SSME's are done by the other side of Boeing. Merlin |
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Quoted: I want to see the wrench they use to torque the head bolts. And I want to know how much torque the bolts are spec'ed to, and how they apply it. CJ When I worked in the Cryogenics plant at Kadena Air Base in Okinawa, we had to use an adjustable wrench that came up to my shoulder when stood on end and then a 10 foot piece of pipe as a cheater bar with 3 people to loosen and tighten bolts on some huge air compressors. Doubt that would work on that thing though! |