corrupt Posted May 8, 2007 Share Posted May 8, 2007 Ive recently modified my crankpully which runs the waterpump/alternator, by welding another pulley on front for the drive belt of a supercharger in doing so made the factory bolt too short. I went out and bought a longer bolt as a replacement. my question is: The factory nut has a strength of 10.9 on the end and the new one ive got has a strength of 8.8, is this going to be safe? I would imagine there isnt that much pressure on this nut while the crank is spinning as they pulley is turned via a keyway and this nut is just keeping the pulley on the keyway? What do you guys think? Should i not worry and just chuck some loctite on the thread for good measure? Quote Link to comment Share on other sites More sharing options...
Gaz Posted May 8, 2007 Share Posted May 8, 2007 I dunno about welding two togthwer. Cast Dont have much choice tho. Quote Link to comment Share on other sites More sharing options...
peteretep Posted May 8, 2007 Share Posted May 8, 2007 whats 10.9 strength? kN? Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted May 8, 2007 Share Posted May 8, 2007 they're grades. possibly find 8.8's stronger. dunno. call steelmasters, they have a branch in auckland Quote Link to comment Share on other sites More sharing options...
corrupt Posted May 8, 2007 Author Share Posted May 8, 2007 I dunno about welding two togthwer. Cast Dont have much choice tho. standard one is cast, the one i attached was steel, off a sugayru aircon/powersteering ot something. was the mean arc job but im certain itll hold. Quote Link to comment Share on other sites More sharing options...
Gaz Posted May 8, 2007 Share Posted May 8, 2007 Welding onto cast greatly weakens it tho. Quote Link to comment Share on other sites More sharing options...
Ogre Posted May 8, 2007 Share Posted May 8, 2007 i dont know about fords, but mitsi has numbers on the bolts, but it means the torque that it should have applied....number means somthing when deciphered using some manuel thing. Quote Link to comment Share on other sites More sharing options...
Gaz Posted May 8, 2007 Share Posted May 8, 2007 The numbers on the end of bolts is the tensile stregth. Why dont ya just get the same as the one that was in there? Quote Link to comment Share on other sites More sharing options...
corrupt Posted May 8, 2007 Author Share Posted May 8, 2007 done a little bit of research ........................................................................8.8................10.9 Proof Load Stress, MPa ...........................600..................830 Tensile Yield Strength, MPa, Min............660 .................940 Tensile Ultimate Strength, MPa, Min. ....830 ................1040 think ill just use what i have for now and maybe try find a bolt with a 10.9 rating when i got time. Quote Link to comment Share on other sites More sharing options...
corrupt Posted May 8, 2007 Author Share Posted May 8, 2007 The numbers on the end of bolts is the tensile stregth.Why dont ya just get the same as the one that was in there? didnt notice markings till i got them home etc, but think ill try get the right one for piece of mind. Anyone know of any specialised bolt/nut shops which could be the go, rather than mitre10mega where i gots this? Quote Link to comment Share on other sites More sharing options...
V8Pete Posted May 8, 2007 Share Posted May 8, 2007 I'd be more worried about the pulleys being out of balance etc with two welded together. Lynch me if I'm wrong. Quote Link to comment Share on other sites More sharing options...
Burntrubber Posted May 8, 2007 Share Posted May 8, 2007 8.8 should be ok. I think tensile grade's go from 4.6 which is mild steel up to 14.9 from memory. Quote Link to comment Share on other sites More sharing options...
Gaz Posted May 8, 2007 Share Posted May 8, 2007 ^^ Balance is prob a big thing too as Pete said. Also.. from memory.. a bolt is considered High Tensile ober 7 Def dont quote me on that tho. Quote Link to comment Share on other sites More sharing options...
corrupt Posted May 8, 2007 Author Share Posted May 8, 2007 yep balance is one thing, i done this as good as i could myself, if it turns out shit and i run into problems with balancing/welds shit, ill prob just go down to pickapart get another two pulleys for 10buck and get an engineer or something to do it for me. the factory pulley is a heavy piece and the pulley i welded on is less than half its weight/welds are pretty even around it. they will also be 99.9% true to eachother, both pulleys were the same diameter so was pretty easy to get them lined up in a vice. Quote Link to comment Share on other sites More sharing options...
corrupt Posted May 8, 2007 Author Share Posted May 8, 2007 ^^ Balance is prob a big thing too as Pete said.Also.. from memory.. a bolt is considered High Tensile ober 7 Def dont quote me on that tho. the packet they came in says high tensile, and has the letter B on it which might be a different system my main question of all this is, how much pressure is actually on a bolt which is just holding a pulley in place? no real strain is on it when engine is going, only strain would be the torque setting, which reminds me i must get a torque wrench, been guessing for years Quote Link to comment Share on other sites More sharing options...
V8Pete Posted May 8, 2007 Share Posted May 8, 2007 my main question of all this is, how much pressure is actually on a bolt which is just holding a pulley in place? no real strain is on it when engine is going, only strain would be the torque setting, which reminds me i must get a torque wrench, been guessing for years How big's the bolt? Quote Link to comment Share on other sites More sharing options...
alfalfa Posted May 8, 2007 Share Posted May 8, 2007 http://www.yellowpages.co.nz/Pages/Search/Results/Cached/0,2837,a6001_c799_d0_l3907_m0,00.html Quote Link to comment Share on other sites More sharing options...
corrupt Posted May 8, 2007 Author Share Posted May 8, 2007 my main question of all this is, how much pressure is actually on a bolt which is just holding a pulley in place? no real strain is on it when engine is going, only strain would be the torque setting, which reminds me i must get a torque wrench, been guessing for years How big's the bolt? standard one is m12x1.5 40mm, new one is m12x1.5 50mm edit: bolt also holds the pulleys with a fat as washer, 40mm diameter and 5mm thick if that matters to what you are thinking. Quote Link to comment Share on other sites More sharing options...
corrupt Posted May 8, 2007 Author Share Posted May 8, 2007 http://www.yellowpages.co.nz/Pages/Search/Results/Cached/0,2837,a6001_c799_d0_l3907_m0,00.html thanks man, might actually go see these cunts "Manufacturing Suppliers Ltd (MSL)", just up the road from where i work. Quote Link to comment Share on other sites More sharing options...
peteretep Posted May 8, 2007 Share Posted May 8, 2007 we buy heaps of stuff from them through my work, EDL is also good for bolts I didnt really read exactly what your doing but could you not buy some rod and get it threaded, or even buy 12mm threaded rod and cut it to suit? Quote Link to comment Share on other sites More sharing options...
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