nootysupra Posted February 17, 2015 Share Posted February 17, 2015 You mean "strip", no more likelihood of a bolt head rounding off in a bad female thread than a good one. The thread's the issue. I did indeed - it's been a long day already! Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 17, 2015 Share Posted February 17, 2015 (edited) Oi, now look sunshine, don't blame me if the thing strips, I make a suggestion, use it entirely at your own risk, take other advice from metallurgists, physicists, your religious leaders, but don't come whining if it suddenly goes bang and you split your knuckles, bang your head and electrocute yourself on an exposed conductor. I have my own problems, and this isn't going to be another of them Edited February 17, 2015 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
T2 MSW Posted February 17, 2015 Share Posted February 17, 2015 Oi, now look sunshine, don't blame me if the thing strips, I make a suggestion, use it entirely at your own risk, take other advice form metallurgists, physicists, your religious leaders, but don't come whining if it suddenly goes bang and you split your knuckles, bang your head and electrocute yourself on an exposed conductor. I have my own problems, and this isn't going to be another of them You have such a way with words Chris - this brightened up my day Quote Link to comment Share on other sites More sharing options...
Dnk Posted February 17, 2015 Share Posted February 17, 2015 Oi, now look sunshine, don't blame me if the thing strips, I make a suggestion, use it entirely at your own risk, take other advice form metallurgists, physicists, your religious leaders, but don't come whining if it suddenly goes bang and you split your knuckles, bang your head and electrocute yourself on an exposed conductor. I have my own problems, and this isn't going to be another of them Lmao Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 17, 2015 Author Share Posted February 17, 2015 Oi, now look sunshine, don't blame me if the thing strips, I make a suggestion, use it entirely at your own risk, take other advice from metallurgists, physicists, your religious leaders, but don't come whining if it suddenly goes bang and you split your knuckles, bang your head and electrocute yourself on an exposed conductor. I have my own problems, and this isn't going to be another of them relax, when I have absolutely no knowledge about threads and their strength, I am of course have to ask people that are having the knowledge to this, I should not be the only one who has been in such a similar situatuon ...... Quote Link to comment Share on other sites More sharing options...
nootysupra Posted February 17, 2015 Share Posted February 17, 2015 relax, when I have absolutely no knowledge about threads and their strength, I am of course have to ask people that are having the knowledge to this, I should not be the only one who has been in such a similar situatuon ...... No, but I think you're the only person I know who openly admits it and then attempts it anyway. No amount of knowledge from anyone given over the internet / trumpet will automatically give you the skill required to catch that thread before it's too late. Since you've gone to the extent of getting it machined out - I think it would be foolish to not get someone experienced enough to torque the thing up. By experienced, I mean doesn't need to ask on a forum regarding torque figures on half shafted threads. Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 17, 2015 Author Share Posted February 17, 2015 No, but I think you're the only person I know who openly admits it and then attempts it anyway. No amount of knowledge from anyone given over the internet / trumpet will automatically give you the skill required to catch that thread before it's too late. Since you've gone to the extent of getting it machined out - I think it would be foolish to not get someone experienced enough to torque the thing up. By experienced, I mean doesn't need to ask on a forum regarding torque figures on half shafted threads. We all have our opinion, and we should all be allowed too without this kind off tone, but it could be I was fortunate that there were some who had been in a similar situation, and could tell what they have gained from the experience and what they have could tighten them too maxium, and still have the same security as some that had not been broken a bolt .. I can hardly believe all switches to a new crank, because one broken bolt .. Quote Link to comment Share on other sites More sharing options...
Krister Posted February 19, 2015 Share Posted February 19, 2015 (edited) Good point, Google shows some people quoting 36 ft lbs plus 90 degrees. My factory manual shows 36 ft lbs, period. See attachment. Correct is 49Nm / 36ft.lbs + 90 degrees: https://dl.dropboxusercontent.com/u/32139684/fwbolts.PNG If you are worried about it stripping, I'd just put red loctite and torque it something in between, the other bolts will keep the flywheel in place fine. Edited February 19, 2015 by Krister (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 19, 2015 Share Posted February 19, 2015 Euro spec manual shows 36 ft lbs then + 90 degrees too. Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 19, 2015 Author Share Posted February 19, 2015 i am very thankfull for all your helps, i will torque as mush as i can, and i really hope that that at least can torque it to 49nm, and be done with that Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 19, 2015 Share Posted February 19, 2015 The bolts are mainly in shear loading, not tension loading. Basically they are there mainly to stop the crank and flywheel turning independently, not to hold the front face of the flywheel to the back face of the crank flange, although obviously is that is a part of their function As such their torque isn't quite as critical as a rod bolt, or head bolt, that's mainly in tension, rather than shear. So you are fortunate in that regard, I think it'll be fine! Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 19, 2015 Author Share Posted February 19, 2015 Ok and it is stille posible to run it hard, with no chance off problems? i now everthing will breake at some point, i just want to now if it holds the same still if the thread not was broke Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 19, 2015 Share Posted February 19, 2015 What's the engine spec? So long as it's nothing ludicrous, or you are attempting drag racing, it should be fine Quote Link to comment Share on other sites More sharing options...
Digsy Posted February 19, 2015 Share Posted February 19, 2015 The bolts are mainly in shear loading, not tension loading. Basically they are there mainly to stop the crank and flywheel turning independently, not to hold the front face of the flywheel to the back face of the crank flange, although obviously is that is a part of their function As such their torque isn't quite as critical as a rod bolt, or head bolt, that's mainly in tension, rather than shear. So you are fortunate in that regard, I think it'll be fine! I have to disagree with you there, Chris. I've never come across a crank nose, cam nose, flywheel or any other torque transmitting joint that relied on shear loading of the bolt. If it is a face to face joint then its always torque transmitted through the friction between the two faces which is a function of the clamp load. I've done several cranks from scratch and the flywheel palm has always been designed to transmit the instantaneous torque from the crank torsionals that are present between the more or less constantly rotating flywheel and the torsionally vibrating crankshaft. Drive on a face, a taper or a spline. Never a bolt or a key That's how it is in OEM-world, anyways. God knows what you racing types get away with Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 20, 2015 Author Share Posted February 20, 2015 What's the engine spec? So long as it's nothing ludicrous, or you are attempting drag racing, it should be fine Little bpu and around 500 hp Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 20, 2015 Author Share Posted February 20, 2015 (edited) I have to disagree with you there, Chris. I've never come across a crank nose, cam nose, flywheel or any other torque transmitting joint that relied on shear loading of the bolt. If it is a face to face joint then its always torque transmitted through the friction between the two faces which is a function of the clamp load. I've done several cranks from scratch and the flywheel palm has always been designed to transmit the instantaneous torque from the crank torsionals that are present between the more or less constantly rotating flywheel and the torsionally vibrating crankshaft. Drive on a face, a taper or a spline. Never a bolt or a key That's how it is in OEM-world, anyways. God knows what you racing types get away with and what you are saying is ??? to According to mit problem can i do i safe or not ??? it my sound stupid, but i not sure about it is to my problem, or just a answer to chris Edited February 20, 2015 by jza800 (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 20, 2015 Share Posted February 20, 2015 I have to disagree with you there, Chris. I've never come across a crank nose, cam nose, flywheel or any other torque transmitting joint that relied on shear loading of the bolt. If it is a face to face joint then its always torque transmitted through the friction between the two faces which is a function of the clamp load. I've done several cranks from scratch and the flywheel palm has always been designed to transmit the instantaneous torque from the crank torsionals that are present between the more or less constantly rotating flywheel and the torsionally vibrating crankshaft. Drive on a face, a taper or a spline. Never a bolt or a key That's how it is in OEM-world, anyways. God knows what you racing types get away with What I was meaning is that the flywheel is rotational, not reciprocal, so doesn't subject the bolts and threads to the same tension changes seen by rod bolts, or head / main bolts. If the clamping force on the flywheel bolts slacken to no longer allow full friction face drive, the loads become mainly shear, but of course that's a failure in the immediate offing. Quote Link to comment Share on other sites More sharing options...
Digsy Posted February 20, 2015 Share Posted February 20, 2015 What I was meaning is that the flywheel is rotational, not reciprocal, so doesn't subject the bolts and threads to the same tension changes seen by rod bolts, or head / main bolts. Yes, I get you I just ran this through my bolt calculator. Assuming the flywheel bolt is M10x1.5 grade 10.9 and the crank is forged steel with a UTS around 900MPa then the bolt can be tightened to full torque (which is 50Nm, slightly more than 36lb-ft) with only 7.1mm of thread, so with 15mm everything should be fine. The crank is steel, isn't it?? Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 20, 2015 Author Share Posted February 20, 2015 It is new stock bolts, i havent messure the total thread length, only that i am missing about 5 to 7mm off thread at the front off the crankshaft. It is a stock crankshaft. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 20, 2015 Share Posted February 20, 2015 Yes, I get you I just ran this through my bolt calculator. Assuming the flywheel bolt is M10x1.5 grade 10.9 and the crank is forged steel with a UTS around 900MPa then the bolt can be tightened to full torque (which is 50Nm, slightly more than 36lb-ft) with only 7.1mm of thread, so with 15mm everything should be fine. The crank is steel, isn't it?? The stock crank is steel, yes, not cast iron. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 20, 2015 Share Posted February 20, 2015 It is new stock bolts, i havent messure the total thread length, only that i am missing about 5 to 7mm off thread at the front off the crankshaft. It is a stock crankshaft. This has absolutely nothing to do with you, just get on with nailing the damned thing together And take no notice of Digsy, his firm make plastic cars that need rebuilding before they've done 500 miles... If they actually manage that much! Quote Link to comment Share on other sites More sharing options...
Digsy Posted February 20, 2015 Share Posted February 20, 2015 and take no notice of digsy, his firm make plastic cars that need rebuilding before they've done 500 miles... If they actually manage that much! Moderator! Quote Link to comment Share on other sites More sharing options...
jza800 Posted February 27, 2015 Author Share Posted February 27, 2015 damm i have tried to put the bolt in the broken hole, with that result, that the thread was to short, so the bolt couldent be torque at all, i have talked to the machine shop, and they mentioned this possibility, they would weld the hole, and make a new hole the same place as stock, and make some new thread to the stock bolts.. someone knows to this method Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 27, 2015 Share Posted February 27, 2015 You can't just weld up something like a crankshaft, and certainly not with it still in the engine Can you get a longer bolt? Would need to be shallow headed, or you could use a cap head if you check there's clearance for the clutch plate. Ideally you should take the crank out and replace it. Quote Link to comment Share on other sites More sharing options...
ibby Posted February 27, 2015 Share Posted February 27, 2015 damm i have tried to put the bolt in the broken hole, with that result, that the thread was to short, so the bolt couldent be torque at all, i have talked to the machine shop, and they mentioned this possibility, they would weld the hole, and make a new hole the same place as stock, and make some new thread to the stock bolts.. someone knows to this method You need to go to a fastners company what bolt you need. Like Dixons Hall. You can't just weld up something like a crankshaft, and certainly not with it still in the engine Can you get a longer bolt? Would need to be shallow headed, or you could use a cap head if you check there's clearance for the clutch plate. Ideally you should take the crank out and replace it. Agreed.. every very difficult Quote Link to comment Share on other sites More sharing options...
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