Gearclash Posted August 9 Share Posted August 9 Young man I know is rebuilding the gasoline engine of his late grandfather’s 560. Sent the rods up for reconditioning. They came back with new rod bolts, but on final torque (with a torque wrench) one bolt snapped. Any advice? Quote Link to comment Share on other sites More sharing options...
ksfarmdude Posted August 9 Share Posted August 9 First what Ft Lb are you torquing them too ? we need all the information to get a clearer picture Quote Link to comment Share on other sites More sharing options...
Gearclash Posted August 9 Author Share Posted August 9 I believe he said 60 ft/lbs. Quote Link to comment Share on other sites More sharing options...
ksfarmdude Posted August 9 Share Posted August 9 I would make sure bearings are correct and get all new rod bolts from another source Quote Link to comment Share on other sites More sharing options...
hillman Posted August 9 Share Posted August 9 44 minutes ago, Gearclash said: Young man I know is rebuilding the gasoline engine of his late grandfather’s 560. Sent the rods up for reconditioning. They came back with new rod bolts, but on final torque (with a torque wrench) one bolt snapped. Any advice? throw them all out and try to get ARP bolts Quote Link to comment Share on other sites More sharing options...
1566Hog Posted August 9 Share Posted August 9 That’s not a fun sound and feel when a bolt like that bolt breaks! I was rebuilding the engine of a Ford Fairlane about 20 years ago for a friend I was working with. Rolled in all new bearings. Borrowed a torque wrench from the guy we were working for (harvest run in KS, so we didn’t have any of our own tools with us.) Ended up snapping a main bearing bolt. Felt like an idiot, but then I broke a second one!!!!! At this point, I’m wondering what one earth is going on. Found out the torque wrench was way off. Luckily Ford had an engine plant in Hutchinson, KS where we were, and the guy we were working for knew a couple employees. He hooked us up with 2 more bolts. I was real nervous, but real cautious torquing the rest. I figured I better find a different torque wrench when I did the rest. Still running 20 years later. 😀 Quote Link to comment Share on other sites More sharing options...
ksfarmdude Posted August 9 Share Posted August 9 13 minutes ago, 1566Hog said: That’s not a fun sound and feel when a bolt like that bolt breaks! I was rebuilding the engine of a Ford Fairlane about 20 years ago for a friend I was working with. Rolled in all new bearings. Borrowed a torque wrench from the guy we were working for (harvest run in KS, so we didn’t have any of our own tools with us.) Ended up snapping a main bearing bolt. Felt like an idiot, but then I broke a second one!!!!! At this point, I’m wondering what one earth is going on. Found out the torque wrench was way off. Luckily Ford had an engine plant in Hutchinson, KS where we were, and the guy we were working for knew a couple employees. He hooked us up with 2 more bolts. I was real nervous, but real cautious torquing the rest. I figured I better find a different torque wrench when I did the rest. Still running 20 years later. 😀 That brings back a memory I had as a yonger fellar I had a 54 yr chevy medium duty truck we used for hauling hay years ago I replaced all the bearings mains and rods and only used a breaker bar to tighten the cap bolts using my best guess for torquing them it ran forever til the truck itself wore out Quote Link to comment Share on other sites More sharing options...
Gearclash Posted August 9 Author Share Posted August 9 I will post what he said his target torque was if he gets back to me. He called me on Saturday last week wondering what I thought of the situation. I suggested checking that the torque wrench calibration isn’t way off; also wondered about the quality of the replacement bolt. He does not know who supplied the bolts but he was going to ask the shop that sent the rods out if they knew. 1 hour ago, ksfarmdude said: years ago I replaced all the bearings mains and rods and only used a breaker bar to tighten the cap bolts using my best guess for torquing them it ran forever til the truck itself wore out Interesting note. Machinery’s Handbook (27th Edition) has a section in it regarding the accuracy of measuring the clamping force of bolts. Rather eye opening to note that using a torque wrench is but one notch better than an educated guess! 2 Quote Link to comment Share on other sites More sharing options...
snoshoe Posted August 9 Share Posted August 9 IH used two different bolts in that engine. A truss headed bolt (had notches in the head). Torqued at 45 ft lb. They were to be replaced by a place bolt. Torqued to 50 ft lb. Never replaced any of those nor had reason to regret. 2 Quote Link to comment Share on other sites More sharing options...
HydroTek Posted August 9 Share Posted August 9 60 is way too much on a gasser rod bolt , no wonder the bolt snapped 80 on the mains 90 final on the head -- use 3 steps Quote Link to comment Share on other sites More sharing options...
stronger800 Posted August 9 Share Posted August 9 I have never worked on a gas engine. I was wondering how 60 could snap anything, unless it was poor quality. Now I know. Interesting Quote Link to comment Share on other sites More sharing options...
hillman Posted August 9 Share Posted August 9 8 hours ago, snoshoe said: IH used two different bolts in that engine. A truss headed bolt (had notches in the head). Torqued at 45 ft lb. They were to be replaced by a place bolt. Torqued to 50 ft lb. Never replaced any of those nor had reason to regret. 60 is high for 3/8 bolt ! If he torqued up all of them and just one snapped I would replace all of them after they got stretched. I am sure you would 2 Quote Link to comment Share on other sites More sharing options...
Gearclash Posted August 10 Author Share Posted August 10 Update. I talked to the young fella tonight again. He said he had torqued everything up to 48 ft/lbs; threads were oiled. The book he had called for 45-50 ft/lbs. He was rechecking the bolts with the wrench still set at 48 ft/lbs when the offending rod bolt turned rather than clicked the wrench, then snapped. He did increase the torque by steps. Quote Link to comment Share on other sites More sharing options...
Gearclash Posted August 10 Author Share Posted August 10 The failed bolt Quote Link to comment Share on other sites More sharing options...
R190 Posted August 10 Share Posted August 10 Also I would try to compare his torque wrench to another one with a bolt and nut in a vise. 1 Quote Link to comment Share on other sites More sharing options...
Mudfly Posted August 10 Share Posted August 10 13 hours ago, Gearclash said: The failed bolt Hard to see the grain structure on that failure, but from what I can see it looks like a brittle fracture. I would say likely a poor quality bolt with inadequate heat treatment. I would agree with the others, replace all with something of known better quality. Cheap insurance and some piece of mind. 1 1 Quote Link to comment Share on other sites More sharing options...
snoshoe Posted August 10 Share Posted August 10 I sure wouldn't call it brittle. Looks like plenty of stretch before it gave up. 2 Quote Link to comment Share on other sites More sharing options...
Mudfly Posted August 10 Share Posted August 10 13 minutes ago, snoshoe said: I sure wouldn't call it brittle. Looks like plenty of stretch before it gave up. It did neck down, but look at the grain structure. Picture isn't great, but looks like rock candy to me, which would indicate large grain structure. Ductile shear or tensile failure would look different. Either way, something was not right there. Quote Link to comment Share on other sites More sharing options...
Gearclash Posted August 10 Author Share Posted August 10 4 hours ago, Mudfly said: Hard to see the grain structure on that failure, but from what I can see it looks like a brittle fracture. 3 hours ago, Mudfly said: It did neck down, but look at the grain structure. Picture isn't great, but looks like rock candy to me, which would indicate large grain structure. Ductile shear or tensile failure would look different. Either way, something was not right there. I haven’t laid eyes on these parts myself but when I last talked to the guy doing the work he said himself that the surface of the break looked strange, different than a typical broken bolt. 5 hours ago, R190 said: Also I would try to compare his torque wrench to another one with a bolt and nut in a vise. I recommended the same thing. Quote Link to comment Share on other sites More sharing options...
hillman Posted August 11 Share Posted August 11 your friend should buy a lottery ticket this week because he is very lucky. Had that not snapped I think he would have had a ventilated crankcase in the near future 2 1 Quote Link to comment Share on other sites More sharing options...
Gearclash Posted October 6 Author Share Posted October 6 Follow up and hopefully closure to this topic. The young fella working on this engine took the offending bolts back to the original seller. He got a run around about it, but the seller conceded it was not a mis calibrated torque wrench. Turned out the bolts were from Reliance. Seller gave the young guy his money back. Young guy bought new bolt from a local CNH dealer. New bolts had different marking on the head so hopefully not the same junk. Reinstalling the new bolts from CNH was uneventful. Long may this 560 continue to run! 3 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.