John Howe Posted November 14, 2006 Share Posted November 14, 2006 I'm sure mine states 20 ft/lbs - most certainly in the relms of scaffolding poles JH Deliveries by Saffron, the yellow 230bhp Sausage delivery machine Link to comment Share on other sites More sharing options...
GTD Posted November 14, 2006 Share Posted November 14, 2006 When this happened to my k series it really did some damage to the bottom end - good luck that you hit the off switch faster than I did! Heading back to Blighty! Link to comment Share on other sites More sharing options...
Griff Posted November 14, 2006 Author Share Posted November 14, 2006 Here's the result from my bolt torque programme except I only have data for ISO M14 x 2.0 - 6G threads (not the 1.5 thread mentioned above). I also have various values for friction but assumed self colour, unlubricated. According to this the max torque should be 159Nm. By my reckoning you'd need a lower torque than this with a finer thread pitch (smaller thread gradient) to achieve the same bolt tension but maybe the extra surface area cancels this out? Even so, mentions of 205Nm (about 150 lbf-ft) from the Rover manual confuse the issue even more. I'm not too happy running such a crucial bolt at close to 90% of yield when there are so many other vibration and fatigue issues, not to mention big +/- tolerances on most torque wrenches. By the way, oiling threads reduces required torque to 152Nm - not that significant And double checked the conversion of units too - it's 1.0 Nm = 0.737561 lbf-ft. M14 x 2.0 - 6g ISO 898 Part 1 Grade 10.9 0.2% Yield stress = 900.0 N/mm² Bolt Dia = 14.0 mm Bolt head A/F dim = 22.0 mm Thread Pitch = 2.00 mm Thread pitch dia = 12.7 mm Inc thread angle = 60.00 deg Effective dia = 12.50 mm Minor dia = 11.20 mm Clearance Hole Dia = 16.0 mm Effective bolt head dia taken as 19.0 mm BOLT Black oxide steel nut or bolt Self finished steel face Coefficient of friction no lubrication = 0.10 to 0.18 THREAD Black oxide finish steel bolt Self finish steel internal thread Coefficient of friction no lubrication = 0.12 to 0.15 TORQUE (lower values of coefficients of friction) Thread friction + Tightening torque = 88.1 N-m Bolt head friction torque = 69.4 N-m TORQUE (higher values of coefficients of friction) Thread friction + Tightening torque = 71.8 N-m Bolt head friction torque = 85.8 N-m STRESSES Max induced tensile stress = 662 N/mm² Max tensile stress / Yield stress = 73.5 % Max induced torsional stress = 270 N/mm² Max combined stress / Yield stress = 90.0 % Min induced tensile stress = 455 N/mm² Min tensile stress / Yield stress = 50.5 % Min induced torsional stress = 219 N/mm² Min combined stress / Yield stress = 65.8 % Link to comment Share on other sites More sharing options...
I reply to every thread Posted November 14, 2006 Share Posted November 14, 2006 So - Up to shear & back half a turn then Link to comment Share on other sites More sharing options...
rj Posted November 14, 2006 Share Posted November 14, 2006 So - Up to shear & back half a turn then 😳 😬 Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted November 14, 2006 Leadership Team Share Posted November 14, 2006 Griff - excuse my ignorance but a translation is required please Build manual states 205Nm. I'd be very wary of torquing to any less with the number that have undone! I admit I also use Loctite, and have always been satisfied that it's there to stay. Stu. Link to comment Share on other sites More sharing options...
Griff Posted November 14, 2006 Author Share Posted November 14, 2006 From the bolt torque program I used, torque needed to reach a given tension is greater when using thread locking compound - same other parameters gave 166Nm. Link to comment Share on other sites More sharing options...
Dobuy Posted November 18, 2006 Share Posted November 18, 2006 What is it with you blo**dy engineers, can't you follow simple instructions, rather than going of investigating tensile strength's and modulus'sss of elasticity. Should have stuck to the pink projectile 😬 Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted November 18, 2006 Leadership Team Share Posted November 18, 2006 Griff - it's your computer calculation that's giving a torque of 166Nm, and it's your pulley that fell off 😳. Think I'd maybe go with the build manual figure of 205Nm then! Before you say it, no, I'm not trying to stir up a heated debate, it's just an observation! Stu. Link to comment Share on other sites More sharing options...
Griff Posted November 18, 2006 Author Share Posted November 18, 2006 It's the "bl**dy engineers who keep your planes in the air Neil 🙆🏻 😬 Hope you're still around after the 26th? Stu - I never checked this bolt in the couple of months I've had the car, but I'm not happy with 205Nm when this seems beyond the capacity of the bolt and more than other respected builders seem to be using. BTW the new bolt supplied by CC doesn't have a proper load marking on the top so I'm not confident it's a 10.9 grade. Anyhow, some time off tomorrow to have a fiddle so fingers crossed nothing worse happened making all this discussion academic. Cheers! Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted November 18, 2006 Leadership Team Share Posted November 18, 2006 I think (from memory) that none of the crank bolts I've used have had any markings on either! Stu. Link to comment Share on other sites More sharing options...
Gridgway Posted November 19, 2006 Share Posted November 19, 2006 a cautionary tale in terms of other damage...the reason the bolt came out the front of my r500 engine was that the flywheel fretted its bolts away, became loose and the vibration er vibrated the bolt out the front! The engine was toast at this point. It sounds to be pretty unlikely to apply to yours, but forewarned... Graham Link to comment Share on other sites More sharing options...
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